US20090318494A1

US20090318494A1 - Pyrazolo[3,4-b]pyridine compounds, and their use as pde4 inhibitors

Info

Publication number: US20090318494A1
Application number: US12/375,695
Authority: US
Inventors: David George Allen; Nicola Mary Aston; Naimisha Trivedi; Christopher David Edlin
Original assignee: Glaxo Group Ltd
Current assignee: Glaxo Group Ltd
Priority date: 2006-08-01
Filing date: 2007-08-01
Publication date: 2009-12-24
Also published as: EP2046787B1; HRP20110434T1; ATE504586T1; DE602007013762D1; DK2046787T3; PL2046787T3; JP2009545579A; EP2046787A1; TW200840818A; US20080058369A1; US20090325952A1; CY1111625T1; AU2007280214A1; PT2046787E; CA2659539A1; US8003663B2; WO2008015416A1; HK1127603A1; SI2046787T1; CL2007002349A1

Abstract

The invention provides a compound of formula (I) or a salt thereof:

wherein Ar has the sub-formula (w), (y), (z1) or (z2):

wherein the several groups are defined herein below, and the use of these compounds as inhibitors of phosphodiesterase type IV (PDE4).

Description

The present invention relates to pyrazolo[3,4-b]pyridine compounds or salts thereof, processes for their preparation, intermediates usable in these processes, and pharmaceutical compositions containing the compounds or salts. The invention also relates to the use of the pyrazolo[3,4-b]pyridine compounds or salts thereof in therapy, for example as inhibitors of phosphodiesterase type IV (PDE4) and/or for the treatment and/or prophylaxis of inflammatory and/or allergic diseases such as chronic obstructive pulmonary disease (COPD), asthma, or rhinitis (e.g. allergic and/or non-allergic rhinitis).

BACKGROUND TO THE INVENTION

Phosphodiesterase 4 inhibitors (PDE4 inhibitors) may be useful in the treatment and/or prophylaxis of a variety of diseases/conditions, especially inflammatory and/or allergic diseases, in mammals such as humans, for example: chronic obstructive pulmonary disease (COPD) (e.g. chronic bronchitis and/or emphysema), asthma, rhinitis (e.g. allergic and/or non-allergic rhinitis), rheumatoid arthritis, atopic dermatitis, psoriasis, urticaria, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, septic shock, inflammatory bowel disease (e.g. ulcerative colitis and/or Crohn's disease), reperfusion injury of the myocardium and/or brain, chronic glomerulonephritis, endotoxic shock, or adult respiratory distress syndrome, in mammals such as humans.
Chronic obstructive pulmonary disease (COPD) is often characterised by the presence of airflow obstruction due to chronic bronchitis and/or emphysema (e.g., see S. L. Wolda, Emerging Drugs, 2000, 5(3), 309-319).
PDE4 inhibitors, for example cilomilast and roflumilast, are thought to be effective in the treatment of COPD. For example, see S. L. Wolda, Emerging Drugs, 2000, 5(3), 309-319; Z. Huang et al., Current Opinion in Chemical Biology, 2001, 5: 432-438; H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; A. M. Vignola, Respiratory Medicine, 2004, 98, 495-503; D. Spina, Drugs, 2003, 63(23), 2575-2594; and references cited in the aforementioned publications; G. Krishna et al., Expert Opinion on Investigational Drugs, 2004, 13(3), 255-267 (see especially pp. 259-261 and refs. 102-111 and 201 therein); and B. J. Lipworth, The Lancet, 2005, 365, 167-175.
The PDE4 inhibitor cilomilast (Ariflo™) at 15 mg orally twice daily appears to improve forced expiratory volume in 1s (FEV₁) in COPD patients (C. H. Compton et al., The Lancet, 2001, vol. 358, 265-270), and appears to have antiinflammatory effects in COPD patients (E. Gamble et al., Am. J. Respir. Crit. Care Med., 2003, 168, 976-982). On cilomilast, see also R. D. Border et al., Chest, 2003, vol. 124 Suppl. 4, p. 170S (abstract) and J. D. Eddleston et al., Am. J. Respir. Crit. Care Med., 2001, 163, A277 (abstract). The PDE4 inhibitor roflumilast appears to show small improvements in FEV₁in COPD patients (see B. J. Lipworth, The Lancet, 2005, 365, 167-175, and refs 49-50 therein). PDE4 inhibitors are thought to be effective in the treatment and/or prophylaxis of asthma (e.g. see M. A. Giembycz, Drugs, February 2000, 59(2), 193-212; Z. Huang et al., Current Opinion in Chemical Biology, 2001, 5: 432-438; H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; P. J. Barnes, Nature Reviews-Drug Discovery, October 2004, 831-844; B. J. Lipworth, The Lancet, 2005, 365, 167-175; and references cited in the aforementioned publications).
The PDE4 inhibitor roflumilast, given orally at 500 ug once daily for 9 days, is reported to be effective in improving rhinal airflow during the treatment period (compared to placebo), in humans with histories of allergic rhinitis but asymptomatic at screening, and who were challenged with intranasal allergen provocation (pollen extracts) daily beginning the third day of treatment and each time approx. 2 hours after study drug administration (B. M. Schmidt et al., J. Allergy & Clinical Immunology, 108(4), 2001, 530-536).
PDE4 inhibitors may be effective in the treatment of rheumatoid arthritis (e.g. see H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; and A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; and references cited in these publications).
PDE4 inhibition has been suggested for the treatment of inflammatory bowel disease (e.g. ulcerative colitis and/or Crohn's disease), see K. H. Banner and M. A. Trevethick, Trends Pharmacol. Sci., August 2004, 25(8), 430-436.
For the use of PDE4 inhibitors in atopic dermatitis, see for example:

J. M. Hanifin et al., “Type 4 phosphodiesterase inhibitors have clinical and in vitro anti-inflammatory effects in atopic dermatitis”, J. Invest. Dermatol., 1996, 107(1), 51-56; which reports reductions of inflammatory parameters in atopic dermatitis patients treated with PDE4 inhibitor CP80,633 (0.5% ointment, twice daily topical application);
C. E. M. Griffiths et al., “Randomized comparison of the type 4 phosphodiesterase inhibitor cipamfylline cream, cream vehicle and hydrocortisone 17-butyrate cream for the treatment of atopic dermatitis”, Br. J. Dermatol., 2002, 147(2), 299-307, which reports that cipamfylline (0.15%) cream is significantly more effective than vehicle, but significantly less effective than hydrocortisone 17-butyrate (0.1%) cream, in the treatment of atopic dermatitis patients;
T. C. Roos et al., “Recent advances in treatment strategies for atopic dermatitis”, Drugs, 2004, 64(23), 2639-2666 (see e.g. page 2657 and refs. 201-209 therein);
A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473 (e.g. see p. 470); and
H. J. Dyke et al., Expert Opinion Invest. Drugs, 2002, 11(1), 1-13 (e.g. see p. 7 and refs. 74, 75 and 76 cited therein);
and references cited in the above references.

For the use of the PDE4 inhibitors SB 207499 (cilomilast) and AWD 12-281 in mouse models of the allergic type of dermatitis, see W. Bäumer et al., Eur. J. Pharmacol., 2002, 446, 195-200 and W. Bäumer et al., J. Pharmacy Pharmacol., 2003, 55, 1107-1114.
WO 2004/056823 A1 (PCT/EP2003/014867, Glaxo Group Limited) discloses certain pyrazolo[3,4-b]pyridine compounds or salts thereof; and their use as PDE4 inhibitors.
WO 2004/024728 A2 (PCT/EP2003/011814, Glaxo Group Limited) discloses pyrazolo[3,4-b]pyridine compounds or salts thereof with a 4-NHR³group and a 5-C(O)—X group, according to the following formula, wherein X is NR⁴R⁵or OR⁵a, and R²is a hydrogen atom (H), methyl or C₁fluoroalkyl. These pyrazolo[3,4-b]pyridine compounds and salts are disclosed as being inhibitors of phosphodiesterase type IV (PDE4):
WO 2004/024728 has been reviewed, and WO 2004/056823 mentioned, in Expert Opin. Ther. Patents, 2005 (January edition), 15(1), 111-114.
Further pyrazolo[3,4-b]pyridine compounds or salts thereof, and their use as PDE4 inhibitors, are disclosed in patent publications WO 2005/058892 A1 (PCT/EP2004/014490), WO 2005/090348 A1 (PCT/GB2005/000983), WO 2005/090352 A1 (PCT/EP2005/003038), WO 2005/090353 A1 (PCT/GB2005/000976), WO 2005/090354 A1 (PCT/GB2005/000987) (all Glaxo Group Limited). Of these, WO 2005/090348 A1 discloses pyrazolo[3,4-b]pyridine compounds or salts thereof with a 4-NHR³group and a 5-C(O)—NH—W group, according to the following formula, wherein W is Ar, —CR⁴R⁵Ar or a group (y) or (y1), and R²is C_2-6alkyl, C_3-6cycloalkyl or —(CH₂)_n ⁴C_3-6cycloalkyl:
Copending patent application PCT/GB2006/003626, published on 5 Apr. 2007 as WO 2007/036733 A1, discloses pyrazolo[3,4-b]pyridine compounds of the following formula or salts thereof, and their use as PDE4 inhibitors:
Copending patent application PCT/GB2006/003627, published on 5 Apr. 2007 as WO 2007/036734 A1, discloses N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-3-methyl-5-isoxazolecarboxamide or a salt thereof, and its use as PDE4 inhibitor.

THE INVENTION

We have now found new pyrazolo[3,4-b]pyridine compounds having a long side-chain containing a basic nitrogen atom, which compounds inhibit phosphodiesterase type IV (PDE4).
The present invention therefore provides a compound of formula (I) or a salt thereof (in particular, a pharmaceutically acceptable salt thereof:
wherein Ar has the sub-formula (w), (y), (z1) or (z2):
wherein:
Q¹is NH or NMe, in which case Q²is —C(O)—, —S(O)₂—, —C(O)NH— or —C(O)NMe-;
or Q¹is a bond or —O—, in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe;
or Q¹is —S(O)₂—, in which case Q²is NH, NMe or a bond;
Q³is a bond, NH or NMe;
and L is (CH₂)_nwherein n is 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13;
or L is —(CH₂)_m ¹—O—(CH₂)_m ²—, wherein it is the —(CH₂)_m ²— which is bonded to the NR⁵R⁶group, and wherein m¹is 1, 2, 3, 4, 5, 6, 7, 8 or 9, and m²is 2, 3, 4, 5, 6, 7, 8 or 9; provided that m¹+m²is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, and provided that when m¹is 1 then Q²is —C(O)— and Q³is a bond;
and R⁵is a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, —CH₂CH₂OH, —CH₂CH(Me)OH, —CH₂CH₂CH₂OH, —CH₂CH₂OMe, or —CH₂CH₂CH₂OMe; and R⁶is C_1-4alkyl, or R⁶is C_1-4alkyl substituted by one OH or OC_1-3alkyl (e.g. OMe) substituent which is not substituted at the alkyl carbon atom which is bonded to the nitrogen atom of the NR⁵R⁶group (for example R⁶can be —CH₂CH₂OH, —CH₂CH(Me)OH, —CH₂CH₂CH₂OH, —CH₂CH₂CH₂CH₂OH, —CH₂CH₂OMe, or —CH₂CH₂CH₂OMe);
or R⁵and R⁶taken together are —(CH₂)₂—X—(CH₂)₂—, —(CH₂)₂—X—(CH₂)₃—, —(CH₂)_p ¹—, —CHR^7a—(CH₂)_p ²—, or —(CH₂)_p ³—CHR^7b—(CH₂)_p ⁴—; in which:
X is O or NR⁸wherein R⁸is a hydrogen atom (H) or C_1-3alkyl (e.g. H or methyl);
R^7ais —CH₂OH, —CH₂OC_1-3alkyl (e.g. —CH₂OMe), —CH₂CH₂OH, —CH₂CH₂OC_1-3alkyl (e.g. —CH₂CH₂OMe), or C_1-3alkyl such as methyl (e.g. R^7acan be —CH₂OH or preferably —CH₂OMe);
R^7bis OH, OC_1-3alkyl (e.g. OMe), —CH₂OH, —CH₂OC_1-3alkyl (e.g. —CH₂OMe), —CH₂CH₂OH, —CH₂CH₂OC_1-3alkyl (e.g. —CH₂CH₂OMe), or C_1-3alkyl such as methyl (e.g. R^7bcan be OH or OMe);
p¹is 4, 5 or 6 (e.g. 4 or 5),
p²is 3, 4 or 5 (e.g. 3 or 4),
p³is 1 or 2 and p⁴is 2, 3 or 4 (e.g. 2 or 3), provided that p³+p⁴is 3, 4 or 5 (e.g. 3 or 4);
and wherein, in sub-formula (y):
A, B, D, E and F independently are C—H or nitrogen (N); wherein one or two of A, B, D, E and F are nitrogen (N) and the remainder of A, B, D, E and F are C—H;
and the Q¹-Q²-L-NR⁵R⁶group of sub-formula (y) is substituted at a ring carbon atom of the six-membered heteroaryl ring of sub-formula (y);
and wherein sub-formulae (z1) and (z2) are connected to the carbonyl carbon atom of formula (I) at a ring carbon atom within (z1) and (z2);
and wherein, in sub-formulae (z1) and (z2):
G is O or S or NR⁹wherein R⁹is a hydrogen atom (H) or methyl;
J is C—R^9J, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N),
M is C—R^9M, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N), and
Q is C—R^9Q, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N);
wherein no more than two of J, M and Q are nitrogen (N);
wherein R^9J, R^9Mand R^9Qindependently are a hydrogen atom (H) or methyl; provided that no more than one of R^9J, R^9Mand R^9Qis methyl;
and wherein:
R¹is C_1-3alkyl, —CH₂—C_1-2fluoroalkyl, or —CH₂CH₂OH;
R²is a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, n-butyl, C_1-2fluoroalkyl, cyclopropyl, cyclobutyl, or (cyclopropyl)methyl-;
R⁴is a hydrogen atom (H), methyl or ethyl; and
R³is optionally substituted C_4-7cycloalkyl, or optionally substituted mono-unsaturated-C_5-7cycloalkenyl, or an optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc), or a bicyclic group of sub-formula (ee);
in which n¹and n²independently are 1 or 2; and in which Y is O, S, SO₂, or NR¹⁰; where R¹⁰is a hydrogen atom (H), methyl, C(O)NH₂, C(O)-methyl, or C(O)—C₁fluoroalkyl;
and wherein, when R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl optionally substituted on a ring carbon(s) with one or two substituents independently being: oxo (═O); OH; methoxy; C₁fluoroalkoxy; NH₂; C_1-2alkyl; C₁fluoroalkyl; —CH₂OH; —CH(Me)OH; —CH₂CH₂OH; —CH₂NH₂; —C(O)OH; —C(O)NHR²⁴wherein R²⁴is H or methyl; —C(O)R²⁵wherein R²⁵is methyl; fluoro; hydroxyimino (═N—OH); or (C_1-2alkoxy)imino (═N—OR²⁶where R²⁶is C_1-2alkyl); and wherein any OH, methoxy, fluoroalkoxy or NH₂substituent is not bonded to the R³ring carbon bonded to the —NH— group of formula (I);
and wherein, when R³is the optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc), then the heterocyclic group of sub-formula (aa), (bb) or (cc) is optionally substituted on a ring carbon(s) with one or two oxo (═O) substituents;
and wherein, when R³is optionally substituted mono-unsaturated-C_5-7cycloalkenyl, then the cycloalkenyl is optionally substituted on a ring carbon with one substituent being fluoro or methyl, and the R³ring carbon bonded to the —NH— group of formula (I) does not partake in the cycloalkenyl double bond;
and wherein:
when R³is the heterocyclic group of sub-formula (aa) and Y is NR¹⁰, then R¹⁰is not C(O)-methyl, or C(O)—C₁fluoroalkyl; and
when R³is the heterocyclic group of sub-formula (bb) and Y is NR¹⁰, then R¹⁰is not methyl; and
when R³is the heterocyclic group of sub-formula (cc), then Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H or methyl;
and wherein:
when R³is optionally substituted C_4-7cycloalkyl, then any —C(O)NHR²⁴or —C(O)R²⁵substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or at the 3- or 4-position of a R³cyclopentyl ring; or at the 4-position of a R³cyclohexyl ring; or at the 3-, 4-, 5- or 6-position of a R³cycloheptyl ring (wherein, in this connection, the 1-position of the R³cycloalkyl ring is deemed to be the connection point to the —NH— in formula (I), that is the ring atom connecting to the —NH— in formula (I));
and wherein:
when R³is optionally substituted C_4-7cycloalkyl, then any OH, methoxy, fluoroalkoxy, —CH₂OH, —CH(Me)OH, —CH₂CH₂OH, —CH₂NH₂, or —C(O)OH substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or at the 3- or 4-position of a R³cyclopentyl ring; or at the 3-, 4- or 5-position of a R³cyclohexyl ring; or at the 3-, 4-, 5- or 6-position of a R³cycloheptyl ring.
In compounds, for example in the compounds of formula (I), an “alkyl” group or moiety may be straight-chain or branched. Alkyl groups, for example C_1-8alkyl or C_1-6alkyl or C_1-4alkyl or C_1-3alkyl or C_1-2alkyl, which may be employed include C_1-6alkyl or C_1-4alkyl or C_1-3alkyl or C_1-2alkyl such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, or n-hexyl or any branched isomers thereof such as isopropyl, t-butyl, sec-butyl, isobutyl, 3-methylbutan-2-yl, 2-ethylbutan-1-yl, or the like.
A corresponding meaning is intended for “alkoxy”, “alkylene”, and like terms derived from alkyl. For example, “alkoxy” such as C_1-6alkoxy or C_1-4alkoxy or C_1-2alkoxy includes methoxy, ethoxy, propyloxy, and oxy derivatives of the alkyls listed above. “Alkylsulfonyl” such as C_1-4alkylsulfonyl includes methylsulfonyl (methanesulfonyl), ethylsulfonyl, and others derived from the alkyls listed above. “Alkylsulfonyloxy” such as C_1-4alkylsulfonyloxy includes methanesulfonyloxy (methylsulfonyloxy), ethanesulfonyloxy, et al.
“Cycloalkyl”, for example C_3-8cycloalkyl (e.g. C_4-7cycloalkyl), includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. Suitably, a C_3-8cycloalkyl group can be C_3-6cycloalkyl or C_5-6cycloalkyl or C_4-7cycloalkyl or C_6-7cycloalkyl, that is contains a 3-6 membered or 5-6 membered or 4-7 membered or 6-7 membered carbocyclic ring.
“Fluoroalkyl” includes alkyl groups with one, two, three, four, five or more fluorine substituents, for example C_1-4fluoroalkyl or C_1-3fluoroalkyl or C_1-2fluoroalkyl such as monofluoromethyl, difluoromethyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl (CF₃CH₂—), 2,2-difluoroethyl (CHF₂CH₂—), 2-fluoroethyl (CH₂FCH₂—), etc. “Fluoroalkoxy” includes C_1-4fluoroalkoxy or C_1-2fluoroalkoxy such as trifluoromethoxy, pentafluoroethoxy, monofluoromethoxy, difluoromethoxy, etc.
A halogen atom (“halo”) present in compounds, for example in the compounds of formula (I), means a fluorine, chlorine, bromine or iodine atom (“fluoro”, “chloro”, “bromo” or “iodo”), for example fluoro, chloro or bromo.
When the specification states that atom or moiety A is “bonded” or “attached” to atom or moiety B, it means that atom/moiety A is directly bonded to atom/moiety B usually by means of a covalent bond or a double covalent bond, and excludes A being indirectly attached to B via one or more intermediate atoms/moieties (e.g. excludes A-C-B); unless it is clear from the context that another meaning is intended.
In one suitable embodiment, Ar has the sub-formula (w) or (y), in particular (w). In another embodiment, Ar has the sub-formula (y), (z1) or (z2).
In one particular embodiment, Ar has the sub-formula (w).
When Ar has the sub-formula (y), then Ar can be of sub-formula (y1), (y2) or (y3):
When Ar has the sub-formula (y), then, in one embodiment, Ar is of sub-formula (y1) or (y3), in particular of sub-formula (y1).
When Ar has the sub-formula (y), then in one embodiment Ar is for example of sub-formula (y1a), (y1b), (y1c), (y1d), (y1e), (y1f), (y2a), (y2b), (y2c), (y2d), (y3a), (y3b), (y3c), (y3d), (y3e) or (y3)f:
When Ar has the sub-formula (z1), then Ar can for example have sub-formula (z1A) or (z1B):
When Ar has the sub-formula (z1A) or (z1B), then in one embodiment Ar can for example have one of the following sub-formulae:
When Ar has the sub-formula (z2), then Ar can for example have sub-formula (z2A):
When Ar has the sub-formula (z2A), then in one embodiment Ar can for example have one of the following sub-formulae:
In sub-formulae (z1) and (z2), in one embodiment, no more than one of J, M and Q are nitrogen (N).
In sub-formulae (z1) and (z2), in one embodiment, R^9J, R^9Mand R^9Qare all a hydrogen atom (H).
In one embodiment,
Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—, —S(O)₂— or —C(O)NH— (e.g. —C(O)— or —S(O)₂—);
or Q¹is a bond or —O—, in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH);
or Q¹is —S(O)₂—, in which case Q²is NH or NMe or a bond (e.g. NH or NMe such as NH).
In one embodiment, suitably, Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—;
or Q¹is a bond, in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH).
Suitably, Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—;
or Q¹is a bond, in which case Q²is a bond.
Q³can for example be NH or a bond.
Suitably, Q³is a bond.
L is (CH₂)_nor L is —(CH₂)_m ¹—O—(CH₂)_m ²—.
Typically, L is (CH₂)_n.
Suitably, n is 5, 6, 7, 8, 9, 10 or 11, such as 5, 6, 7, 8, 9 or 10.
Preferably, n is 6, 7, 8 or 9, such as 7.
m¹can for example be 2, 3, 4, 5, 6, 7, 8 or 9. In particular, m¹is 2, 3, 4, 5 or 6. Suitably, m¹is 3, 4 or 5. Preferably, m¹is 4.
In particular, m²is 2, 3, 4, 5 or 6. Suitably, m²is 3, 4 or 5. Preferably, m²is 4.
m¹+m²can for example be 4, 5, 6, 7, 8, 9, 10, 11 or 12. In particular, m¹+m²is 4, 5, 6, 7, 8, 9 or 10.
Suitably, m¹+m²is 6, 7, 8, 9 or 10. Preferably, m¹+m²is 8.
In one embodiment, when L is (CH₂)_n, then:
Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—, —S(O)₂—, —C(O)NH— or —C(O)NMe- (e.g. —C(O)— or —S(O)₂—);
or Q¹is a bond or —O— (e.g. a bond), in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH);
or Q¹is —S(O)₂—, in which case Q²is NH or NMe or a bond (e.g. NH or NMe such as NH);
and when L is —(CH₂)_m ¹—O—(CH₂)_m ²—, then:
Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—;
or Q¹is a bond or —O— (e.g. a bond), in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH).
In one embodiment, when L is (CH₂)_n, then:
Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—, —S(O)₂—, —C(O)NH— or —C(O)NMe- (e.g. —C(O)— or —S(O)₂—);
or Q¹is a bond or —O— (e.g. a bond), in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH);
or Q¹is —S(O)₂—, in which case Q²is NH or NMe or a bond (e.g. NH or NMe such as NH);
and when L is —(CH₂)_m ¹—O—(CH₂)_m ²—, then:
Q¹is a bond or —O— (e.g. a bond), in which case Q²is a bond.
In one embodiment, suitably, when L is (CH₂)_n, then:
Q¹is NH or NMe (e.g. NH), in which case Q²is —C(O)—;
or Q¹is a bond, in which case Q²is a bond;
or Q¹is —C(O)—, in which case Q²is NH or NMe (e.g. NH);
and when L is —(CH₂)_m ¹—O—(CH₂)_m ²—, then Q¹is a bond, and Q²is a bond.
Suitably, when L is (CH₂)_n, then:
Q¹is NH, in which case Q²is —C(O)—;
or Q¹is a bond, in which case Q²is a bond;
and when L is —(CH₂)_m ¹—O—(CH₂)_m ²—, then Q¹is a bond, and Q²is a bond.
Suitably, (when R⁵and R⁶are not taken together), R⁵is a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, or —CH₂CH₂OH. Preferably, R⁵is methyl, ethyl, n-propyl or isopropyl, such as methyl.
Suitably, (when R⁵and R⁶are not taken together), R⁶is —CH₂CH₂OH, —CH₂CH(Me)OH, —CH₂CH₂CH₂OH, —CH₂CH₂CH₂CH₂OH, —CH₂CH₂OMe, or —CH₂CH₂CH₂OMe. Preferably, R⁶is —CH₂CH₂OH.
In one embodiment, when R⁵and R⁶are taken together, then R⁵and R⁶taken together can be —(CH₂)₂—X—(CH₂)₂—, —(CH₂)_p ¹—, —CHR^7a—(CH₂)_p ²—, or —(CH₂)_p ³—CHR^7b—(CH₂)_p ⁴—.
Suitably, when R⁵and R⁶are taken together, then R⁵and R⁶taken together are —(CH₂)₂—X—(CH₂)₂—, —(CH₂)_p ¹—, or —CHR^7a—(CH₂)_p ²—.
R⁸can be for example a hydrogen atom (H) or methyl, such as methyl.
X is suitably O.
R^7acan for example be —CH₂OH, —CH₂OMe, —CH₂CH₂OH, —CH₂CH₂OMe, or C_1-3alkyl such as methyl.
R^7ais suitably —CH₂OH or preferably —CH₂OMe.
R^7bcan for example be OH, OMe, —CH₂OH, or —CH₂OMe or methyl.
R^7bcan for example be OH or OMe.
p¹can suitably be 4 or 5, such as 4.
p²can suitably be 3 or 4, such as 3.
p⁴can suitably be 2 or 3, provided that p³+p⁴is 3, 4 or 5.
p³+p⁴can suitably be 3 or 4.
When R¹is C_1-3alkyl or —CH₂—C_1-2fluoroalkyl, it can be straight-chained or branched. When R¹is C_1-3alkyl then it can be methyl, ethyl, n-propyl, or isopropyl. When R¹is —CH₂—C_1-2fluoroalkyl: then R¹can for example be —CH₂—C₁fluoroalkyl such as 2,2,2-trifluoroethyl (CF₃CH₂—), 2,2-difluoroethyl (CHF₂CH₂—), or 2-fluoroethyl (CH₂FCH₂—).
In the invention, R¹is C_1-3alkyl (e.g. methyl, ethyl or n-propyl), —CH₂—C_1-2fluoroalkyl or —CH₂CH₂OH. R¹for example can be C_1-3alkyl, —CH₂—C₁fluoroalkyl, or —CH₂CH₂OH. Suitably, R¹is C_2-3alkyl (e.g. ethyl or n-propyl), —CH₂—C₁fluoroalkyl (e.g. CF₃—CH₂—) or —CH₂CH₂OH.
Preferably, R¹is ethyl, n-propyl or —CH₂CH₂OH.
Most preferably, R¹is ethyl.
R²can for example be a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, C₁fluoroalkyl (such as CF₃or CHF₂or CH₂F), C₂fluoroalkyl such as C₂F₅or C₁fluoroalkyl-CH₂— [e.g. 2,2,2-trifluoroethyl (CF₃CH₂—), 2,2-difluoroethyl (CHF₂CH₂—) or 2-fluoroethyl (CH₂FCH₂—)], or cyclopropyl.
R²can for example be methyl, ethyl, C₁fluoroalkyl (such as CF₃or CHF₂or CH₂F), or C₂fluoroalkyl such as C₂F₅or C₁fluoroalkyl-CH₂— [e.g. 2,2,2-trifluoroethyl (CF₃CH₂—), 2,2-difluoroethyl (CHF₂CH₂—) or 2-fluoroethyl (CH₂FCH₂—)].
R²can for example be a hydrogen atom (H), methyl, ethyl or C₁fluoroalkyl (such as CF₃or CHF₂or CH₂F). Suitably, R²is a hydrogen atom (H), methyl or ethyl. Alternatively, suitably, R²is methyl, ethyl or C₁fluoroalkyl (such as CF₃or CHF₂or CH₂F).
Preferably, R²is methyl or ethyl.
Most preferably, R²is ethyl.
R⁴can for example be a hydrogen atom (H) or methyl.
Preferably, R⁴is a hydrogen atom (H).
Preferably, in R³there is one substituent on a ring carbon or no substituent on a ring carbon.
Preferably, R³is the optionally substituted C_4-7cycloalkyl or the optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc).
Optionally, when R³is optionally substituted C_4-7cycloalkyl, it is not unsubstituted cyclopentyl. In this case, suitably, R³is optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl.
When R³is optionally substituted C_4-7cycloalkyl, it is suitably optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl, preferably optionally substituted C₆cycloalkyl (i.e. optionally substituted cyclohexyl).
When R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl) optionally substituted on a ring carbon(s) with one or two substituents independently being (e.g. one substituent being): oxo (═O); OH; methoxy; C₁fluoroalkoxy (e.g. trifluoromethoxy or difluoromethoxy); NH₂; C_1-2alkyl such as methyl; C₁fluoroalkyl such as —CH₂F or —CHF₂; —CH₂OH; —CH(Me)OH; —CH₂CH₂OH; —CH₂NH₂; —C(O)OH; —C(O)NHR²⁴wherein R²⁴is H or methyl (preferably H); —C(O)R²⁵wherein R²⁵is methyl; fluoro; hydroxyimino (═N—OH); or (C_1-2alkoxy)imino (═N—OR²⁶where R²⁶is C_1-2alkyl); and wherein any OH, methoxy, fluoroalkoxy or NH₂substituent is not bonded to the R³ring carbon bonded to the —NH— group of formula (I).
When R³is optionally substituted C_4-7cycloalkyl, then R³can suitably be C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl) optionally substituted on a ring carbon(s) with one or two substituents independently being (e.g. one substituent being): oxo (═O); OH; NH₂; C_1-2alkyl such as methyl; C₁fluoroalkyl such as —CH₂F or —CHF₂; —CH₂OH; —CH(Me)OH; —C(O)NHR²⁴wherein R²⁴is H or methyl (preferably H); —C(O)R²⁵wherein R²⁵is methyl; fluoro; hydroxyimino (═N—OH); or (C_1-2alkoxy)imino (═N—OR²⁶where R²⁶is C_1-2alkyl).
Preferably, when R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl) optionally substituted on a ring carbon(s) with one or two substituents independently being (e.g. one substituent being): oxo (═O); OH; methyl; —CH₂F; —CHF₂; —CH₂OH; —C(O)NHR²⁴wherein R²⁴is H; fluoro; hydroxyimino (═N—OH); or methoxyimino (═N—OR²⁶where R²⁶is methyl).
More preferably, when R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl) optionally substituted on a ring carbon(s) with one or two substituents independently being (e.g. one substituent being): oxo (═O); OH; methyl; —C(O)NHR²⁴wherein R²⁴is H; fluoro; or hydroxyimino (═N—OH).
Still more preferably, when R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl) optionally substituted on a ring carbon(s) with one or two substituents independently being (e.g. one substituent being): oxo (═O); OH; —C(O)NHR²⁴wherein R²⁴is H; or hydroxyimino (═N—OH).
In one optional embodiment, in R³, the C_4-7cycloalkyl can be unsubstituted.
When R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, e.g. optionally substituted (C_6-7cycloalkyl or cyclobutyl or C_5-7cycloalkenyl), such as optionally substituted C₆cycloalkyl (optionally substituted cyclohexyl) or optionally substituted cyclohexenyl, the one or two optional substituents on a ring carbon(s) if present suitably can comprise a substituent (for example is or are substituent(s)) at the 3-, 4- and/or 5-position(s), e.g. at the 3- and/or 4-position(s), of the R³cycloalkyl or cycloalkenyl ring.
(In this connection and generally herein, the 1-position of the R³ring, e.g. of the R³cycloalkyl or cycloalkenyl ring, is deemed to be the connection point to the —NH— in formula (I), that is the ring atom connecting to the —NH— in formula (I)).
Suitably, for R³, and in particular when R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, R³is not substituted (other than optionally by alkyl or fluoroalkyl) at the ring atom connecting to the —NH— in formula (I), and R³is not substituted (other than optionally by alkyl, fluoroalkyl or NHR²¹) at the two ring atoms either side of (bonded to) the connecting atom. For example, suitably, for R³, and in particular when R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, R³is not substituted at the ring atom connecting to the —NH— in formula (I), and R³is not substituted at the two ring atoms either side of (bonded to) the connecting atom.
Suitably, for R³, and in particular when R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, the one or two optional R³ring-carbon substituents if present can comprise a substituent (for example is or are substituent(s)):
(a) at the 3-position of a R³cyclobutyl ring, or
(b) at the 3- and/or 4-position(s) of a R³cyclopentyl or cyclopentenyl ring, or
(c) at the 3-, 4- and/or 5-position(s) of a R³cyclohexyl or cyclohexenyl ring, or
(d) at the 3-, 4-, 5- and/or 6-position(s) of a R³cycloheptyl or cycloheptenyl ring, and/or
(f) at the 1-, 2- and/or highest-numbered-position(s) of a R³cycloalkyl or cycloalkenyl ring, for alkyl or fluoroalkyl substituent(s), and/or
(g) at the 2- and/or highest-numbered-position(s) of a R³cycloalkyl or cycloalkenyl ring, for NH₂or fluoro substituent(s).
When R³is optionally substituted C_4-7cycloalkyl, then any OH, methoxy, fluoroalkoxy, —CH₂OH, —CH(Me)OH, —CH₂CH₂OH, —CH₂NH₂, or —C(O)OH substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or at the 3- or 4-position of a R³cyclopentyl ring; or at the 3-, 4- or 5-position of a R³cyclohexyl ring (such as at the 3- or 5-position of a R³cyclohexyl ring especially for any OH substituent); or at the 3-, 4-, 5- or 6-position (e.g. 4- or 5-position) of a R³cycloheptyl ring. Suitably, when R³is optionally substituted C_4-7cycloalkyl, then any OH, methoxy, fluoroalkoxy, —CH₂OH, —CH(Me)OH, —CH₂CH₂OH or —CH₂NH₂, or —C(O)OH substituent (or any OH substituent) on a ring carbon is at the 3- or 4-position of a R³cyclopentyl ring; or more suitably at the 3-, 4- or 5-position, such as at the 3- or 5-position, of a R³cyclohexyl ring.
When R³is optionally substituted C_4-7cycloalkyl, then any —C(O)NHR²⁴or —C(O)R²⁵substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or at the 3- or 4-position of a R³cyclopentyl ring; or at the 4-position of a R³cyclohexyl ring; or at the 3-, 4-, 5- or 6-position (e.g. 4- or 5-position) of a R³cycloheptyl ring. When R³is optionally substituted C_4-7cycloalkyl, then any —C(O)NHR²⁴or —C(O)R²⁵substituent, or any —C(O)NHR²⁴substituent, on a ring carbon is suitably at the 3-position of a R³cyclobutyl ring or at the 4-position of a R³cyclohexyl ring. When R³is optionally substituted C_4-7cycloalkyl, it is preferable for any —C(O)NHR²⁴substituent to be at the 4-position of a R³cyclohexyl ring.
When R³is optionally substituted C_4-7cycloalkyl, any NH₂substituent on a ring carbon is at any position other than the 1-position (the ring atom connecting to the —NH— in formula (I)), e.g. at the 2-, 3-, 4-, 5-, 6- or 7-position. Suitably, any NH₂substituent is at the 2-, 3-, 4-, 5- or 6-position, for example at the 3-, 4- or 5-position or at the 3- or 5-position, of a R³cyclohexyl ring.
When R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, any alkyl or fluoroalkyl substituent on a ring carbon can for example be at the 1-, 2-, 3-, 4-, 5-, 6- or 7-position, for example at the 1-, 2-, 3-, 5- or 6-position, e.g. the 1-position, of the R³ring. Preferably, any such alkyl or fluoroalkyl substituent on a ring carbon is at the 1-, 2-, 3-, 5- or 6-position, or more preferably at the 1-, 3- or 5-position, of a R³cyclohexyl or cyclohexenyl ring.
When R³is optionally substituted C_4-7cycloalkyl or optionally substituted C_5-7cycloalkenyl, any fluoro substituent on a ring carbon can for example be at the 2-, 3-, 4-, 5-, 6- or 7-position, for example at the 2-, 3-, 4-, 5- or 6-position, such as at the 3- or 4-position, of the R³ring. Suitably, any fluoro substituent on a ring carbon is at the 3-, 4- or 5-position, in particular at the 4-position, of a R³cyclohexyl or cyclohexenyl ring.
When R³is optionally substituted C_4-7cycloalkyl, any oxo (═O), hydroxyimino (═N—OH); or (C_1-2alkoxy)imino (═N—OR²⁶) substituent on a ring carbon can for example be at the 3-, 4- or 5-position, e.g. at the 4-position, of the R³cycloalkyl (e.g. C_6-7cycloalkyl e.g. cyclohexyl, or cyclobutyl) ring. Any such substituent can for example be at the 3-position of a R³cyclobutyl ring or at the 4-position of a R³cyclohexyl ring. Preferably, any such substituent is at the 4-position of a R³cyclohexyl ring.
When R³is optionally substituted C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl, optionally substituted), then R³is suitably cyclohexyl (i.e. unsubstituted); or cycloheptyl (i.e. unsubstituted); or cyclohexyl substituted on a ring carbon by one substituent being oxo (═O), OH, NH₂, C_1-2alkyl, C₁fluoroalkyl such as —CH₂F or —CHF₂, —CH₂OH, —CH(Me)OH, —C(O)NHR²⁴wherein R²⁴is H or methyl (preferably H), —C(O)R²⁵, fluoro, hydroxyimino (═N—OH), or (C_1-2alkoxy)imino (═N—OR²⁶wherein R²⁶is C_1-2alkyl); or cyclohexyl substituted by two fluoro substituents; or cyclobutyl (i.e. unsubstituted); or cyclobutyl substituted on a ring carbon with one substituent being oxo (═O), OH, methyl, —CH₂F, —CHF₂, —CH₂OH, —C(O)NHR²⁴wherein R²⁴is H or methyl (preferably H), fluoro, hydroxyimino (═N—OH), or methoxyimino (═N—OR²⁶where R²⁶is methyl). Preferably, when R³is optionally substituted C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl, optionally substituted), then R³is cyclohexyl (i.e. unsubstituted); or cycloheptyl (i.e. unsubstituted); or cyclohexyl substituted on a ring carbon by one substituent being oxo (═O), OH, NH₂, C_1-2alkyl, C₁fluoroalkyl such as —CH₂F or —CHF₂, —CH₂OH, —C(O)NHR²⁴wherein R²⁴is H, fluoro, hydroxyimino (═N—OH), or (methoxy)imino (═N—OR²⁶wherein R²⁶is methyl); or cyclohexyl substituted by two fluoro substituents; or cyclobutyl (i.e. unsubstituted); or cyclobutyl substituted on a ring carbon with one substituent being oxo (═O), OH, methyl, —CH₂F, —CHF₂, —CH₂OH, —C(O)NHR²⁴wherein R²⁴is H, fluoro, hydroxyimino (═N—OH), or methoxyimino (═N—OR²⁶where R²⁶is methyl). More preferably, when R³is optionally substituted C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl, optionally substituted), then R³is cyclohexyl (i.e. unsubstituted); or cyclohexyl substituted on a ring carbon by one oxo (═O), hydroxyimino (═N—OH), —C(O)NH₂, methyl or OH substituent; or cyclobutyl substituted on a ring carbon by one —C(O)NHR²⁴substituent wherein R²⁴is H. The optional substituent can for example be at the 3- or 4-position of the R³cyclohexyl ring. Preferably, when R³is optionally substituted C_4-7cycloalkyl (e.g. C_6-7cycloalkyl or cyclobutyl, optionally substituted), then any OH substituent on a ring carbon is preferably at the 3-position of a R³cyclohexyl ring, and/or any oxo (═O), hydroxyimino (═N—OH), or (C_1-2alkoxy)imino (═N—OR²⁶) substituent on a ring carbon is preferably at the 4-position of a R³cyclohexyl ring or at the 3-position of a R³cyclobutyl ring, and/or any alkyl or fluoroalkyl substituent is preferably at the 1-, 3- or 5-position of a R³cyclohexyl ring.
When R³is optionally substituted cyclobutyl, then R³can preferably be cyclobutyl (i.e. unsubstituted) or more preferably 3-(aminocarbonyl)cyclobutyl (i.e. 3-(aminocarbonyl)cyclobutan-1-yl) (e.g. in a cis or trans configuration, preferably cis).
When R³is optionally substituted cyclopentyl, R³can for example be cyclopentyl (i.e. unsubstituted) or more suitably 3-hydroxy-cyclopentyl.
When R³is optionally substituted C_4-7cycloalkyl (e.g. optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl), R³can for example be cyclobutyl (i.e. unsubstituted), 4-hydroxy-cyclohexyl (i.e. 4-hydroxycyclohexan-1-yl) (e.g. racemic or in a cis or trans configuration), 4-methylcyclohexyl (e.g. racemic), 2-aminocyclohexyl (e.g. racemic or in a cis or trans configuration, preferably trans), 4-aminocyclohexyl (e.g. racemic or in a cis or trans configuration, preferably racemic or cis), 3-oxocyclohexyl, 4-acetylcyclohexyl (e.g. racemic or in a cis or trans configuration, preferably racemic or cis), 4-(1-hydroxyethyl)cyclohexyl (e.g. racemic or in a cis or trans configuration with respect to the ring, preferably racemic or cis), or 3-(hydroxymethyl)cyclohexyl (e.g. racemic or in a cis or trans configuration).
However, when R³is optionally substituted C_4-7cycloalkyl (e.g. optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl), R³is more preferably cyclohexyl (i.e. unsubstituted), cycloheptyl (i.e. unsubstituted), 3-hydroxy-cyclohexyl (i.e. 3-hydroxycyclohexan-1-yl) (e.g. racemic or in a cis or trans configuration, preferably racemic or cis), 4-oxo-cyclohexyl (i.e. 4-oxocyclohexan-1-yl), 4-(hydroxyimino)cyclohexyl (i.e. 4-(hydroxyimino)cyclohexan-1-yl), 4-(C_1-2alkoxyimino)cyclohexyl, 4-(aminocarbonyl)cyclohexyl (i.e. 4-(aminocarbonyl)cyclohexan-1-yl) (e.g. racemic or in a cis or trans configuration, preferably racemic or cis), 1-methylcyclohexyl (e.g. racemic), 3-methylcyclohexyl (e.g. racemic), 4,4-(difluoro)cyclohexyl, 3-aminocyclohexyl (e.g. racemic or in a cis or trans configuration), 4-(hydroxymethyl)cyclohexyl (e.g. racemic or in a cis or trans configuration), or 3-(aminocarbonyl)cyclobutyl (i.e. 3-(aminocarbonyl)cyclobutan-1-yl) (e.g. racemic or in a cis or trans configuration, preferably cis).
A “cis configuration” in general includes mixtures of configurations wherein the cis configuration is the major component.
When R³is optionally substituted C_4-7cycloalkyl (e.g. optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl), R³is still more preferably cyclohexyl (i.e. unsubstituted), 3-hydroxy-cyclohexyl (i.e. 3-hydroxycyclohexan-1-yl) (preferably racemic or in a cis configuration), 4-oxo-cyclohexyl (i.e. 4-oxocyclohexan-1-yl), 4-(hydroxyimino)cyclohexyl (i.e. 4-(hydroxyimino)cyclohexan-1-yl), 4-(aminocarbonyl)cyclohexyl (i.e. 4-(aminocarbonyl)cyclohexan-1-yl) (preferably racemic or in a cis configuration), or 3-(aminocarbonyl)cyclobutyl (i.e. 3-(aminocarbonyl)cyclobutan-1-yl) (preferably racemic or in a cis configuration).
When R³is optionally substituted mono-unsaturated-C_5-7cycloalkenyl, suitably it is optionally substituted mono-unsaturated-C_5-6cycloalkenyl, preferably optionally substituted mono-unsaturated-C₆cycloalkenyl (i.e. optionally substituted mono-unsaturated-cyclohexenyl=optionally substituted cyclohexenyl). For example, the R³cyclohexenyl can be optionally substituted cyclohex-3-en-1-yl.
When R³is optionally substituted mono-unsaturated-C_5-7cycloalkenyl, suitably the R³cycloalkenyl (e.g. cyclohexenyl) is substituted on a ring carbon with one fluoro substituent or is unsubstituted. For example, the R³optionally substituted cycloalkenyl can be cyclohex-3-en-1-yl (i.e. unsubstituted) or 4-fluoro-cyclohex-3-en-1-yl.
For R³cycloalkenyl, the optional substituent(s) on a ring carbon can for example be at the 1-, 2-, 3-, 4-, 5- or 6-position(s) of the cycloalkenyl ring.
When R³is the heterocyclic group of sub-formula (aa), (bb) or (cc), then Y is suitably O or NR¹⁰. When R³is the heterocyclic group of sub-formula (aa) or (bb), then Y is preferably O or N—C(O)—NH₂.
R¹⁰can for example be a hydrogen atom (H), methyl, C(O)NH₂, C(O)-methyl or C(O)—C₁fluoroalkyl.
Suitably, R¹⁰is not methyl.
Suitably, R¹⁰is a hydrogen atom (H), C(O)NH₂, C(O)-methyl or C(O)—C₁fluoroalkyl (e.g. C(O)—CF₃). More suitably, R¹⁰is H, C(O)NH₂or C(O)-methyl; in particular C(O)NH₂.
When R³is the heterocyclic group of sub-formula (aa), (bb) or (cc), then it is preferable that R³is the heterocyclic group of sub-formula (aa) or (bb), more preferably of sub-formula (bb).
In sub-formula (bb), n¹is preferably 1. In sub-formula (cc), n²is preferably 1. That is, six-membered rings are preferred in the R³heterocyclic group.
In the invention, the R³heterocyclic group of sub-formula (aa), (bb) or (cc) is optionally substituted on a ring carbon with one or two (e.g. one) substituents being oxo (═O).
In the R³heterocyclic group of sub-formula (aa), (bb) or (cc), any oxo (═O) substituent on a ring carbon is suitably on a carbon atom bonded (adjacent) to Y. In one embodiment, any oxo (═O) substituent on a ring carbon can be on a carbon atom bonded (adjacent) to Y only when Y is O or NR¹⁰, for example only when Y is NR¹⁰.
In the R³heterocyclic group of sub-formula (aa), (bb) or (cc), any oxo (═O) substituent on a ring carbon can suitably be at the 2-, 3-, 4-, 5- or 6-position of the R³heterocyclic ring. For example any ring-carbon oxo (═O) substituent(s) can be: at the 2-, 4- or 5-position(s) (e.g. 2-position or 4-position, or two oxo substituents at 2- and 4-positions) of a R³heterocyclic group of sub-formula (aa), at the 2-, 4-, 5- or 6-position(s) (e.g. 4-position) of a six-membered R³heterocyclic group of sub-formula (cc) wherein n²is 1, at the 2-, 3-, 5-, 6- or 7-position(s) (e.g. 5-position) of a seven-membered R³heterocyclic group of sub-formula (bb) wherein n¹is 2, or at the 2-, 4-, 5-, 6- or 7-position(s) (e.g. 2-position) of a seven-membered R³heterocyclic group of sub-formula (cc) wherein n²is 2.
(In this connection and generally herein, the 1-position of the R³heterocyclic ring is deemed to be the connection point to the —NH— in formula (I), that is the ring atom connecting to the —NH— in formula (I), and the remaining positions of the ring are then numbered so that the ring heteroatom takes the lowest possible number).
In the R³heterocyclic group of sub-formula (aa), (bb) or (cc), no substitution is allowed at the 1-position ring-carbon of the R³heterocyclic ring.
However, it is generally preferable that, in R³, the heterocyclic group of sub-formula (aa), (bb) or (cc) is not substituted on a ring carbon (i.e. is not substituted on any ring carbon).
When R³is the heterocyclic group of sub-formula (aa) and Y is NR¹0, then R¹⁰is not C(O)-methyl, or C(O)—C₁fluoroalkyl.
In one preferable embodiment, when R³is the heterocyclic group of sub-formula (aa), then Y is O, S, SO₂, NH or NC(O)NH₂(in particular Y can be O, S, NH or NC(O)NH₂, such as NC(O)NH₂).
When R³is the heterocyclic group of sub-formula (bb) and Y is NR¹⁰(e.g. when NHR³is
wherein the —NH— connection point of the NHR³group to the 4-position of the pyrazolopyridine of formula (I) is underlined), then R¹⁰is not methyl.
Therefore, when R³is the heterocyclic group of sub-formula (bb), then Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H, C(O)NH₂, C(O)-methyl or C(O)—C₁fluoroalkyl (e.g. C(O)—CF₃). When R³is the heterocyclic group of sub-formula (bb), then R¹⁰is preferably H, C(O)NH₂or C(O)-methyl, for example C(O)NH₂or C(O)-methyl, more preferably C(O)NH₂.
When R³is the heterocyclic group of sub-formula (cc), then Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H or methyl.
Suitably, when R³is the heterocyclic group of sub-formula (cc), then: either Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H, or NHR³is of sub-formula (m4):
wherein the —NH— connection point of the NHR³group to the 4-position of the pyrazolopyridine of formula (I) is underlined.
Suitably, when R³is the heterocyclic group of sub-formula (cc), then Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H, or Y is O or NR¹⁰wherein R¹⁰is H.
In one embodiment, for sub-formula (bb) and/or for sub-formula (cc), Y is O or NR¹⁰.
When R³is optionally substituted C_4-7cycloalkyl (e.g. optionally substituted C_6-7cycloalkyl or optionally substituted cyclobutyl) or optionally substituted mono-unsaturated-C_5-7cycloalkenyl or an optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc), then a substituent on a ring carbon can be racemic or in the cis or trans configuration with respect to the —NH— group of formula (I) to which R³is attached (bonded). A cis or trans configuration includes mixtures of configurations wherein the stated configuration is the major component. In this context, “racemic” refers to a mixture of isomers containing substantially equal amounts of the cis and trans configurations with respect to a substituent and the —NH— group on the R³ring, and in this context “racemic” does not refer to isomerism at atoms other than R³ring carbon atoms. For example, an OH or —C(O)NHR²⁴substituent on C_6-7cycloalkyl or cyclobutyl can for example be in the cis configuration and/or a NH₂substituent on C_6-7cycloalkyl can for example be racemic or in the cis or trans configuration, with respect to the —NH— group of formula (I) to which R³is attached (bonded), including mixtures of configurations wherein the stated configuration is the major component.
When R³is a bicyclic group of sub-formula (ee), then NHR³can be of sub-formula (c6) or (c7):
wherein the —NH— connection point of the NHR³group to the 4-position of the pyrazolopyridine of formula (I) is underlined.
Preferably, NHR³is of sub-formula (a1), (b), (c), (c 1), (c 2), (c 3), (c 4), (c 5), (c 6), (c 7), (d), (e), (f), (g), (g2), (g4), (h), (i), (j), (k), (k1), (k2), (k3), (L), (m), (m1), (m3), (m4), (n), (o), (o1), (o2), (o3), (p), (p1), (p2), (p3), (p5), (p6), (p9), (p10), (p12), (p13), (p14), (p15), or (q):
In the sub-formulae (a1) to (q) etc above, the —NH— connection point of the NHR³group to the 4-position of the pyrazolopyridine of formula (I) is underlined.
Preferably, NHR³is of sub-formula (c), (c1), (c 2), (c 3), (c 4), (c 5), (c 6), (c 7), (d), (e), (f), (g4), (h), (i), (j), (k), (k1), (k2), (k3), (L), (m), (ml), (m3), (m4), (n), (o), (o1), (o2), (o3), (p), (p2), (p5), (p6), (p9), (p10), (p12), (p13), (p14), (p15) or (q); or preferably NHR³is of sub-formula (al), (c), (c1), (c 2), (c 3), (c 4), (c 5), (c 6), (c 7), (d), (e), (D, (g4), (h), (i), (j), (k), (k1), (k2), (k3), (L), (m), (ml), (m3), (m4), (n), (o), (o1), (o2), (o3), (p), (p1), (p2), (p5), (p6), (p9), (p10), (p12), (p13), (p14), (p15) or (q).
More preferably, NHR³is of sub-formula (c), (c1), (c 4), (c 5), (h), (i), (k), (k2), (k3), (m1), (n), (o), (o2), (o3), (p2), (p5), (p6), (p9), (p10), (p13) or (p15).
NHR³is more preferably of sub-formula (c), (h), (k), (k2), (k3), (n), (o), (o2), (p9) or (p13); still more preferably NHR³is (c), (h), (k2), (k3), (n), (o), (o2), (p9) or (p13).
Most preferably, R³is tetrahydro-2H-pyran-4-yl or 1-(aminocarbonyl)-4-piperidinyl; that is NHR³is most preferably of sub-formula (h) or (k2), as shown above, in particular of sub-formula (h).
When NHR³is of sub-formula (n), then it can be in the trans configuration. But preferably it is in the cis configuration, i.e. preferably it is a cis-(3-hydroxycyclohexan-1-yl)amino group (including mixtures of configurations wherein the cis configuration is the major component), or it is racemic.
When NHR³is of sub-formula (p9), then it can be in the trans configuration. But preferably it is in the cis configuration, i.e. preferably it is a cis-[4-(aminocarbonyl)cyclohexan-1-yl]amino group (including mixtures of configurations wherein the cis configuration is the major component), or it is racemic.
When NHR³is of sub-formula (p12), then it can be in the trans configuration. But, preferably, it is in the cis configuration, i.e. preferably NHR³is a cis-[4-acetylcyclohexan-1-yl]amino group (including mixtures of configurations wherein the cis configuration is the major component), or it is racemic.
When NHR³is of sub-formula (p13), then it can be in the trans configuration. But, preferably, it is in the cis configuration, i.e. preferably NHR³is a cis-[3-(aminocarbonyl)cyclobutan-1-yl]amino group (including mixtures of configurations wherein the cis configuration is the major component), or it is racemic.
The NHR³group of sub-formula (p10), (p14) or (p15), independently, can for example be racemic; or it can be in the cis configuration with respect to the ring (including mixtures of configurations wherein the cis configuration is the major component).
Preferably, the compound of formula (I) or the salt thereof is:

4-({1,6-diethyl-5-[({8-[(2-hydroxyethyl)(methyl)amino]octanoyl}amino)methyl]-1H-pyrazolo[3,4-b]pyridin-4-yl}amino)-1-piperidinecarboxamide,
4-[(1,6-diethyl-5-{[(8-{(2R)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanoyl)amino]methyl}-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide,
4-[(1,6-diethyl-5-{[(8-{(2S)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanoyl)amino]methyl}-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide,
N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-[(2-hydroxyethyl)(methyl)amino]octanamide,
N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2R)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanamide, or
N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2S)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanamide;
or a salt thereof such as a pharmaceutically acceptable salt thereof.

The structures of the above-listed specific compounds or salts, or embodiments (e.g. specific salts) thereof, are given in the Examples hereinafter.
In one optional embodiment of the invention, the compound of formula (I) or the salt thereof can be a compound whose formula is,
or a salt thereof (e.g. the compound or a pharmaceutically acceptable salt thereof).

Salts, Solvates, Isomers, Tautomeric Forms, Molecular Weights, Etc.

Because of their potential use in medicine, the salts of the compounds of formula (I) are preferably pharmaceutically acceptable. Suitable pharmaceutically acceptable salts can include acid addition salts, or less commonly (e.g. if a C(O)OH group is present in the compound) base addition salts.
In one embodiment, a pharmaceutically acceptable acid addition salt is optionally formed by mixing of a compound of formula (I) with a pharmaceutically acceptable inorganic or organic acid (such as hydrobromic, hydrochloric, sulfuric, nitric, phosphoric, succinic, maleic, formic, acetic, propionic, fumaric, citric, tartaric, lactic, benzoic, 1-naphthoic, 1-hydroxy-2-naphthoic (“xinafoic”), salicylic, glutamic such as L-glutamic, aspartic, para-toluenesulfonic, benzenesulfonic, methanesulfonic, ethanesulfonic, naphthalenesulfonic such as 2-naphthalenesulfonic, naphthalenedisulfonic such as 1,5-naphthalenedisulfonic, camphorsulfonic (e.g. 10-camphorsulfonic), 1,2,4-benzenetricarboxylic, hydroxyethylidene-1,1-diphosphonic, or hexanoic acid), optionally in a suitable solvent such as an organic solvent, to give the salt which is usually isolated for example by crystallisation and filtration. The organic solvent used in the pharmaceutically acceptable acid addition salt formation process may e.g. be anhydrous or water-containing. Depending on the properties of and/or suitabilities for use with the compound of formula (I), the organic solvent may be for example selected from methanol, ethanol (e.g. anhydrous), n-propanol (propan-1-ol, e.g. anhydrous), isopropanol (IPA, propan-2-ol, e.g. substantially anhydrous IPA or IPA:water mixtures such as IPA containing about 1-2% water), butanol, pentan-1-ol (e.g. substantially anhydrous), ethyl acetate, methyl isobutyl ketone (MIBK), chloroform, dichloromethane, toluene, or mixtures thereof. A pharmaceutically acceptable inorganic or organic acid can for example be: hydrobromic, hydrochloric, sulfuric, nitric, phosphoric, succinic, maleic, 1-naphthoic, 1-hydroxy-2-naphthoic (“xinafoic”), glutamic such as L-glutamic, para-toluenesulfonic, benzenesulfonic, methanesulfonic, ethanesulfonic, naphthalenesulfonic such as 2-naphthalenesulfonic, naphthalenedisulfonic such as 1,5-naphthalenedisulfonic, camphorsulfonic (e.g. 10-camphorsulfonic and/or (+)-camphorsulfonic), 1,2,4-benzenetricarboxylic, or hydroxyethylidene-1,1-diphosphonic acid.
A pharmaceutically acceptable acid addition salt of a compound of formula (I) can comprise or be for example a hydrobromide (e.g. monohydrobromide or dihydrobromide), hydrochloride (e.g. monohydrochloride or dihydrochloride), sulfate, nitrate, phosphate, succinate (e.g. hemisuccinate), maleate, formate, acetate, propionate, fumarate (e.g. hemifumarate), citrate, tartrate, lactate, benzoate, 1-naphthoate, 1-hydroxy-2-naphthoate (“xinafoate”) (e.g. mono-1-hydroxy-2-naphthoate), salicylate, glutamate such as L-glutamate, aspartate, para-toluenesulfonate (e.g. mono- or di- para-toluenesulfonate), benzenesulfonate, methanesulfonate (e.g. mono- or di-methanesulfonate), ethanesulfonate, naphthalenesulfonate (e.g. 2-naphthalenesulfonate), naphthalenedisulfonate (e.g. 1,5-naphthalenedisulfonate), camphorsulfonate (e.g. 10-camphorsulfonate and/or (+)-camphorsulfonate, e.g. mono-(+)-10-camphorsulfonate), 1,2,4-benzenetricarboxylate, hydroxyethylidene-1,1-diphosphonate, or hexanoate salt.
In one embodiment, a pharmaceutically acceptable base addition salt is optionally formed by reaction of a compound of formula (I) with a suitable inorganic or organic base (e.g. triethylamine, ethanolamine, triethanolamine, choline, arginine, lysine or histidine), optionally in a suitable solvent such as an organic solvent, to give the base addition salt which is usually isolated for example by crystallisation and filtration.
Other suitable pharmaceutically acceptable salts include pharmaceutically acceptable metal salts, for example pharmaceutically acceptable alkali-metal or alkaline-earth-metal salts such as sodium, potassium, calcium or magnesium salts; in particular pharmaceutically acceptable metal salts of one or more carboxylic acid moieties that may be present in the compound of formula (I).
Other non-pharmaceutically acceptable salts, e.g. oxalates or trifluoroacetates, may be used, for example in the isolation of compounds of the invention, and are included within the scope of this invention.
The invention includes within its scope all possible stoichiometric and non-stoichiometric forms of the salts of the compounds of formula (I).
Also included within the scope of the invention are all solvates, hydrates and complexes of compounds and salts of the invention.
Certain compounds or salts included in the present invention may be present as isomers. The present invention includes within its scope all such isomers, including racemates, enantiomers and mixtures thereof.
In the compounds or salts, pharmaceutical compositions, uses, methods of treatment/prophylaxis, methods of preparing, etc. according to the present invention, where a defined isomeric configuration e.g. stereochemical configuration is described or claimed, the invention includes a mixture comprising (a) a major component of the compound or salt which is in the described or claimed configuration, together with (b) one or more minor components of the compound or salt which is/are not in the described or claimed configuration. Preferably, in such a mixture, the major component of the compound or salt which is in the described or claimed configuration represents 70% or more, or 75% or more, more preferably 85% or more, still more preferably 90% or more, yet more preferably 95% or more, yet more preferably 98% or more, of the total amount of compound or salt present in the mixture on a molarity basis.
The percentage of one isomeric/stereochemical component in a mixture of different isomeric/stereochemical components, and if appropriate enantiomeric and/or diastereomeric excesses, can be measured using techniques known in the art. Such methods include the following:
(1) Measurement using NMR (e.g. ¹H NMR) spectroscopy in the presence of chiral agent. One can measure a nuclear magnetic resonance (NMR) spectrum (preferably a ¹H NMR spectrum, and/or a solution-phase NMR spectrum e.g. in CDCl₃or D6-DMSO solvent) of the compound/salt mixture in the presence of a suitable chiral agent which “splits” the NMR peaks of a given atom in different isomers into different peak positions. The chiral agent can be: i) an optically pure reagent which reacts with the compound/salt e.g. to form a mixture of diastereomers, ii) a chiral solvent, iii) a chiral molecule which forms a transient species (e.g. diastereomeric species) with the compound/salt, or iv) a chiral shift reagent. See e.g. J. March, “Advanced Organic Chemistry”, 4th edn., 1992, pages 125-126 and refs. 138-146 cited therein. A chiral shift reagent can be a chiral lanthanide shift reagent such as tris[3-trifluoroacetyl-d-camphorato]europium-(III) or others as described in Morrill, “Lanthanide Shift Reagents in Stereochemical Analysis”, VCH, New York, 1986. Whatever the chiral agent is that is used, usually, the relative integrals (intensities) for the NMR peaks of a given atom or group in different isomers can provide a measurement of the relative amounts of each isomer present.
(2) Measurement using chiral chromatography, especially on an analytical scale. A suitable chiral column which separates the different isomeric components can be used to effect separation, e.g. using gas or liquid chromatography such as HPLC, and/or e.g. on an analytical scale. The peaks for each isomer can be integrated (area under each peak); and a comparison or ratio of the integrals for the different isomers present can give a measurement of the percentage of each isomeric component present. See for example: “Chiral Chromatography”, Separation Science Series Author: T. E. Beesley and R. P. W. Scott, John Wiley & Sons, Ltd., Chichester, UK, 1998, electronic Book ISBN: 0585352690, Book ISBN: 0471974277.
(3) Separation of pre-existing diastereomeric mixtures which are compounds/salts of the invention can be achieved (usually directly, without derivatisation) using separation techniques such as gas or liquid chromatography. Diastereomeric ratios and/or excesses can thereby be derived e.g. from the relative peak areas or relative separated masses.
(4) Conversion with a chiral/optically-active agent and subsequent separation of the resulting isomers, e.g. diastereomers. Conversion can be via derivatisation of a derivatisable group (e.g. —OH, —NHR) on the compound/salt with an optically-active derivatising group (e.g. optically active acid chloride or acid anhydride); or can be via formation of an acid or base addition salt of the compound by treatment of the compound with an optically-active acid or base, such as + or − di-para-toluoyl tartaric acid. After derivatisation, separation of the resulting isomers e.g. diastereomers, can be using gas or liquid chromatography (usually non-chiral); or (especially with isomeric salts) can be by selective crystallisation of a single isomeric e.g. diastereoisomeric salt. Determination of isomeric ratios and/or excesses can be using chromatography peak areas or measurement of mass of each separated isomer.
See e.g. J. March, “Advanced Organic Chemistry”, 4th edn., 1992, pages 120-121 and 126, and refs. 105-115 and 147-149 cited therein.
(5) Measurement of optical activity [alpha] of mixture and comparison with optical activity of pure isomer [alpha]_maxif available (e.g. see J. March, “Advanced Organic Chemistry”, 4th edn., 1992, page 125 and refs. 138-139 cited therein). This assumes a substantially linear relationship between [alpha] and concentration.
Certain of the groups, e.g. heteroaromatic ring systems, included in compounds of formula (I) or their salts may exist in one or more tautomeric forms. The present invention includes within its scope all such tautomeric forms, including mixtures.

Synthetic Process Routes

The following non-limiting processes can generally be used to prepare the compounds of formula (I):
wherein Ar has the sub-formula (w), (y), (z1) or (z2):
Some of the following synthetic processes may be exemplified for compounds of Formula (I) with particular Ar groups (in particular wherein Ar has the sub-formula (y) or (w)) and/or with particular substitution patterns e.g. particular values of Q¹and Q²and Q³and L. However, at least some of these processes are likely to be able to be usable with appropriate modification(s), e.g. modification(s) of starting materials and reagents, which modification(s) may be extensive, for making other compounds of Formula (I).

Process 1A

Compounds of formula (II), which are compounds of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), Q¹is NH, Q²is —C(O)—, and L is (CH₂)_n, wherein R¹, R², R³, R⁴, R⁵, R⁶, and n are as defined herein, and which might be generally representative of some of the compounds of formula (I) wherein Ar has sub-formula (y), or salts thereof, can be prepared by reaction (substitution) of a compound of formula (III), wherein X¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenesulfonate) or a halogen atom, in particular a halogen atom such as preferably a bromine atom, and wherein R¹, R², R³, R⁴and n are as defined herein, with an amine of formula (IV), wherein R⁵and R⁶are as defined herein. Suitable conditions for the reaction include heating in a suitable solvent such as N,N-dimethylformamide, in the presence of a suitable base (e.g. a base having a low nucleophilicity such that it does not substantially displace the X¹leaving group) such as N,N-diisopropylethylamine, e.g. heating at a suitable temperature such as about 70-90° C. e.g. about 80-85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as about 140° C.
In general, the amines of formula (IV) are either commercially available (for example in some cases from Aldrich), known in the literature, or may be prepared e.g. by conventional means.
Compounds of formula (III), wherein R¹, R², R³, R⁴, X¹, and n are as defined herein (in particular where X¹=Br), typically may be prepared from compounds of formula (V), wherein R¹, R², R³and R⁴are as defined herein, by reaction with a suitable acylating agent (VI), wherein X¹and n are as defined herein (in particular where X¹=Br) and X²represents a halogen atom such as a chlorine or bromine atom, preferably a chlorine atom. Suitable conditions include carrying out the reaction in a suitable anhydrous solvent such as dichloromethane or chloroform, in the presence of a suitable base such as N,N-diisopropylethylamine or triethylamine, at a suitable temperature such as from 0° C. to room temperature, and suitably under nitrogen.
Compounds of formula (VI), wherein X¹, X²and n are as defined herein, typically can be prepared from compounds of formula (VII), wherein X¹and n are as defined herein (in particular where X¹=Br), by reaction with for example thionyl chloride (for X²=Cl), phosphoryl chloride (for X²=Cl), or phosphoryl bromide (for X²=Br) (preferably thionyl chloride for X²=Cl), or other suitable reagents e.g. as described in R. C. Larock, Comprehensive Organic Transformations, 2^ndEd, Wiley, 1999. Suitable conditions for X²=Cl include the use of thionyl chloride, e.g. at room temperature, optionally in a suitable non-aqueous (e.g. anhydrous) aprotic organic solvent such as toluene.
Compounds of formula (V), wherein R¹, R², R³and R⁴are as defined herein, can generally be prepared from compounds of formula (VII), wherein R¹, R², R³and R⁴are as defined herein, and X³is a protecting group, by deprotection.
X³can be a nitrogen protecting group e.g. as described in T. W. Greene and P. G. M Wuts Protecting Groups in Organic Synthesis, Wiley 1999. Suitably, X³is tert-butoxycarbonyl (‘BOC’). When X³is the BOC protecting group, standard methods (e.g. as described in Greene) can be used for the deprotection reaction (VIII) to (V), for example treatment with a solution of hydrogen chloride in 1,4-dioxane such as 4M HCl in 1,4-dioxane, e.g. at room temperature.
Compounds of formula (VIII), wherein R¹, R², R³and R⁴are as defined herein, and X³is a protecting group such as BOC, may typically be prepared by reaction between compounds of formula (IX), wherein R¹, R², R³and R⁴are as defined herein, and compounds of formula (X) wherein X³is as defined herein such as BOC and X⁴is a suitable leaving group.
The activated compound (the compound of formula (X)) can for example be an activated ester and X⁴the leaving group thereof. For example the leaving group X⁴can be of sub-formula (bt):
The activated compound of formula (X), e.g. wherein X⁴is of sub-formula (bt), can be formed from the carboxylic acid of formula (Xa), wherein X³is as defined herein such as BOC:
In one embodiment the activated compound of formula (X) wherein X⁴is of sub-formula (bt) is formed from the carboxylic acid of formula (Xa) by the following reaction (a). In this reaction (a), the carboxylic acid (Xa) is reacted with a suitable organic di-substituted carbodiimide, such as 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide [also named 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide] or a salt thereof such as the hydrochloride salt thereof (EDC), or such as N,N′-dicyclohexylcarbodiimide (DCC), followed by reaction of the resulting product with 1-hydroxybenzotriazole (when X₅is CH) or 1-hydroxy-7-azabenzotriazole (when X₅is N). In one embodiment, this reaction (a), to form (X) wherein X⁴is of sub-formula (bt) from (Xa), is carried out in a suitable organic solvent e.g. an aprotic organic solvent (preferably anhydrous) such as N,N-dimethylformamide or acetonitrile, e.g. under anhydrous conditions and/or e.g. at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.). In one optional embodiment, this reaction (a) is carried out in the presence of a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA).
In another embodiment, the activated compound of formula (X) wherein X⁴is of sub-formula (bt) is formed from the carboxylic acid of formula (Xa) by the following reaction (b). In reaction (b), the carboxylic acid (Xa) is reacted with a suitable 1-hydroxybenzotriazole-based or 1-hydroxy-7-azabenzotriazole-based coupling agent, such as (i), (ii), (iii) or (iv):
(i) O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (also called HBTU; when X₂is CH), or
(ii) 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU; when X₂is CH), or
(iii) O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU, when X₂is N), or
(iv) (benzotriazol-1-yloxy)-trispyrrolidinophosphonium hexafluorophosphate (PyBOP; when X₂is CH)).
In one optional embodiment, this reaction (b), to form (X) wherein X⁴is of sub-formula (bt) from (Xa), is carried out in the presence of a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA). In one embodiment, this reaction (b) is usually carried out in the presence of a solvent such as an aprotic organic solvent (e.g. anhydrous solvent) such as N,N-dimethylformamide or acetonitrile, e.g. under anhydrous conditions and/or at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.).
In one alternative embodiment, an activated compound of formula (X) is the product (adduct) formed from the reaction of the carboxylic acid of formula (Xa) with a suitable organic di-substituted carbodiimide (e.g. R′—N═C═N—R″) [wherein the carbodiimide can e.g. be 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or a salt thereof such as the hydrochloride salt thereof (EDC), or dicyclohexylcarbodiimide (DCC)]. In this case, in the activated compound of formula (X) being the carboxylic acid-carbodiimide adduct, X⁴is —O—C(NHR′)═N—R″ or —O—C(NHR″)═N—R′. This is the situation e.g. when the carbodiimide is reacted with the carboxylic acid (Xa) without 1-hydroxybenzotriazole or 1-hydroxy-7-azabenzotriazole being present. In one embodiment, this reaction is carried out in a suitable organic solvent e.g. an aprotic organic solvent (preferably anhydrous) such as N,N-dimethylformamide or acetonitrile, e.g. under anhydrous conditions and/or e.g. at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.). In one optional embodiment, this reaction (a) is carried out in the presence of a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA).
In another alternative embodiment, the activated compound of formula (X) is for example the acid chloride (wherein X⁴is Cl). In one embodiment, this acid chloride is for example formed from the corresponding carboxylic acid (Xa) either (a) by reaction with thionyl chloride, either in an organic solvent such as chloroform or without solvent, or (b) by reaction with oxalyl chloride in N,N-dimethylformamide (e.g. catalytic DMF in dichloromethane or in DMF solvent). When an acid chloride within formula (X) is used to prepare the compound of formula (VIII), the reaction with amine (IX) is usually carried out in the presence of a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA) and/or in a suitable aprotic organic solvent (e.g. anhydrous solvent) such as acetonitrile or dichloromethane, for example at room temperature (e.g. about 18 to about 25° C.). Note: this acid chloride method may not be ideal for Boc-protected compounds.
Compounds of formula (IX), wherein R¹, R²and R³are as defined herein and R⁴represents hydrogen, can be prepared by hydrogenation of an azide compound of formula (XI), wherein R¹, R²and R³are as defined herein, in the presence of a suitable catalyst such as a palladium catalyst, e.g. palladium on carbon, in a suitable solvent such as ethanol, e.g. at a suitable temperature such as room temperature:
Compounds of formula (XI), wherein R¹, R²and R³are as defined herein, may be prepared from compounds of formula (XII), wherein R¹, R²and R³are as defined herein and wherein X⁶is a leaving group such as a halogen atom, mesylate (methanesulfonate), tosylate (p-toluenesulfonate), or triflate (trifluoromethanesulfonate) (suitably a halogen atom such as a chlorine atom).
For example the compounds of formula (XII), e.g. wherein X⁶is Cl, can be reacted with an azide salt such as sodium, lithium or potassium azide, in a suitable solvent such as dimethylsulfoxide such as dry DMSO, e.g. at a suitable temperature such as room temperature, to give compounds of formula (XI).
Compounds of formula (XII) or acid addition salts thereof (e.g. sulfonate such as benzenesulfonate or methanesulfonate salt thereof), wherein R¹, R²and R³and X⁶are as defined herein (e.g. wherein X⁶is Cl, mesylate, tosylate or triflate), can be prepared by reaction of compounds of formula (XIII), wherein R¹, R²and R³are as defined herein, with a suitable reagent such as thionyl chloride (for when X⁶is Cl), oxalyl chloride (for when X⁶is Cl), methanesulfonyl chloride or methanesulfonic anhydride (for when X⁶is mesylate), or para-toluenesulfonyl chloride or para-toluenesulfonic anhydride (for when X⁶is tosylate), preferably thionyl chloride. Suitable conditions, for when X⁶is Cl, include reacting with thionyl chloride in a suitable non-aqueous (e.g. anhydrous) aprotic organic solvent such as toluene or anisole (methoxybenzene), e.g. with heating to ca. 60-90° C. such as to ca. 85° C. (e.g. with toluene), or e.g. at 20±5° C. (e.g. with anisole), and optionally also in the presence of an anhydrous aryl (e.g. phenyl), alkyl (e.g. methyl) or trifluoromethyl sulfonic acid, such as benzenesulfonic acid or methanesulfonic acid (e.g. to prepare the sulfonate such as benzenesulfonate salt of (XII), e.g. when X⁶is Cl, for example to try to improve the stability of the “benzylic” chloride). Alternative conditions include reacting compounds of formula (XIII) with thionyl chloride and methanesulfonic acid or benzenesulfonic acid in a suitable non-aqueous (e.g. anhydrous) aprotic organic solvent such as dichloromethane, e.g. at a suitable temperature such as room temperature.
Preferably, in the process, the compound of formula (XII) or the acid addition salt thereof (e.g. sulfonate such as benzenesulfonate or methanesulfonate salt thereof, and/or e.g. when X⁶is Cl) is not isolated. Rather, it is preferably left in solution, optionally with partial or full exchange of solvents. The solution of the compound of formula (XII) or the acid addition salt thereof (e.g. when X⁶is Cl) can be reacted directly in the next step. Alternatively, compounds of formula (XI) wherein R¹, R²and R³are as defined herein can be prepared directly from compounds of formula (XIII) wherein R¹, R²and R³are as defined herein.
For example, compounds of formula (XI) may be prepared by reacting compounds of formula (XIII) with an azide salt, e.g. sodium azide, in the presence of a halogenating agent such as carbon tetrabromide and a phosphine such as triphenylphosphine under suitable conditions, such as N,N-dimethylformamide, e.g. at a suitable temperature such as between 0° C. and room temperature (see e.g. Toyota et. al. Journal of Organic Chemistry, 2000, 65(21), 7110-7113).
This route, (XIII) to (XI) directly, may be suitable for where R³is a urea-containing group [such as a N-aminocarbonyl-piperidinyl or N-aminocarbonyl-pyrrolidinyl group within sub-formula (bb) or (aa), that is wherein NHR³is of sub-formula (k2) or (k3)], because it is noted that these R³urea-containing groups may not be tolerant of thionyl chloride which may be used in converting (XIII) to (XII) wherein X⁶is Cl and thence to (XI).
In another alternative embodiment of particular interest, an amine compound of formula (IX) or a salt thereof (e.g. HCl salt thereof), wherein R¹, R²and R³are as defined herein and R⁴is as defined herein (in particular where R⁴is a hydrogen atom), may usually be prepared directly from a compound of formula (XII) or an acid addition salt thereof, wherein R¹, R²and R³and X⁶are as defined herein, without first converting to an azide compound of formula (XI). For example, in compound (XII) or the acid addition salt thereof, X⁶can in particular be a chlorine atom. When X⁶is a chlorine atom, a suitable acid addition salt such as an arylsulfonate, alkylsulfonate or trifluoromethylsulfonate salt (in particular a benzenesulfonate or methanesulfonate salt) of the compound of formula (XII) can for example be used, in particular when R¹and R²are ethyl and when R³is of the sub-formula (h) that is when R³is tetrahydro-2H-pyran-4-yl.
This reaction, converting the compound (XII) or the acid addition salt thereof (e.g. sulfonate such as benzenesulfonate salt) to the amine compound (IX) or the salt thereof (e.g. HCl salt), may for example be carried out under suitable conditions, for example by reaction of a compound of formula (XII) or an acid addition salt thereof with an aminating agent. When R⁴represents a hydrogen atom, and optionally for example when X⁶is a chlorine atom, a suitable aminating agent may be used, e.g. an alkali-metal hexamethyldisilazide such as lithium hexamethyldisilazide, sodium hexamethyldisilazide or potassium hexamethyldisilazide (in particular lithium hexamethyldisilazide), in a suitable non-aqueous non-alcohol (aprotic) organic solvent (e.g. anhydrous solvent) such as tetrahydrofuran (THF), for example at a suitable temperature such as about 25 to about 50° C., for example ca. 30-45° C. or ca. 30-40° C. The compound (XII) or the salt thereof is suitably added slowly to a mixture or solution of the alkali-metal hexamethyldisilazide (e.g. lithium hexamethyldisilazide) in the aprotic organic solvent (e.g. THF), to try to minimise alkylation of any in-situ deprotected amine (IX) by the compound (XII) or the salt thereof. The reaction with the suitable aminating agent (e.g. with the alkali-metal hexamethyldisilazide) is suitably followed by treatment with an aqueous acid such as aqueous hydrochloric acid (e.g. 2-10M, e.g. about 5M), for example at a suitable temperature such as from 0° C. to room temperature, for example at 5-15° C. or ca. 10° C. In one particular embodiment, a solution of the produced amine (IX) or the salt thereof in an organic solvent (suitably in an organic solvent having a low water miscibility, such as comprising 2-methyl-THF or a mixture of sec-butanol and isopropanol) is extracted with aqueous base, such as concentrated (e.g. ca. 32% w/w) NaOH solution, to form the amine compound (IX) as the “free base”. Optionally, a mono-acid-addition salt, e.g. monohydrochloride, of the amine (IX) can be formed by mixing the “free base” amine compound (IX) (e.g. in an organic solvent such as comprising 2-methyl-THF or a mixture of sec-butanol and isopropanol) with about 1 equivalent (e.g. 1.03 equiv.) of a suitable acid such as HCl (e.g. aqueous hydrochloric acid such as concentrated aq. HCl e.g. ca. 36% w/w aq. HCl), preferably under conditions such that the mono-acid-addition salt, e.g. monohydrochloride, of the amine (IX) crystallises from a or the organic solvent present.
In one particular simplified embodiment of the conversion of compound (XII) or a salt thereof to amine compound (IX) or a salt thereof, when X⁶is a chlorine atom in the compound of formula (XII) and when R⁴is a hydrogen atom in the compound of formula (IX), the precursor alcohol compound of formula (XIII) or a salt thereof is converted into the amine of formula (IX) or a salt thereof, via the compound of formula (XII) or a salt thereof, without substantially purifying and/or without substantially isolating the compound of formula (XII) or the salt thereof wherein X⁶is a chlorine atom (Cl). In this embodiment, the compound of formula (XII) or the salt thereof wherein X⁶is a chlorine atom can for example be in the form of the benzenesulfonate salt, in particular when R¹and R²are ethyl and when R³is of the sub-formula (h) that is when R³is tetrahydro-2H-pyran-4-yl. In the first step, conversion of compound (XIII) to compound (XII) or a salt thereof wherein X⁶is Cl is optionally carried out using thionyl chloride in a suitable non-aqueous (e.g. anhydrous) aprotic organic solvent such as anisole or toluene, e.g. at 20±5° C. or with heating to ca. 60-90° C., and optionally in the presence of an organic sulfonic acid such as benzenesulfonic acid to prepare the sulfonate e.g. benzenesulfonate salt of (XII), wherein X⁶is Cl. The second step, the compound (XII) or the salt thereof (wherein X⁶is Cl), dissolved and/or suspended in anisole and/or toluene, is optionally converted to compound (IX) or a salt thereof wherein R⁴is H, e.g. as described elsewhere hereinabove or hereinbelow. See Intermediate 7A herein for a specific example of this two-step reaction:
Compounds of formula (XIII), wherein R¹, R², and R³are as defined herein, can be prepared by reaction of compounds of formula (XIV), wherein R¹, R²and R³are as defined herein, and wherein X⁷is an alkyl group such as a C_1-6or C_1-4alkyl (e.g. straight-chain alkyl) group e.g. in particular ethyl, with a suitable reducing agent in a suitable solvent, e.g. at a suitable temperature.
One suitable reducing agent is lithium borohydride, in which case:

- a suitable solvent can for example comprise or be an aprotic organic solvent (e.g. anhydrous) such as tetrahydrofuran (THF, e.g. dry), optionally mixed with toluene (e.g. dry), or THF alone;
- and (for lithium borohydride), preferably, dry methanol (e.g. 3 to 15 equivalents, e.g. about 9 equivalents, but preferably not in very large excess) can be used, in particular in admixture with the suitable aprotic organic solvent such as THF, to speed up the reduction reaction;
- and/or (for lithium borohydride) a suitable reaction temperature can be from room temperature to the reflux temperature, e.g. about 50 to about 75° C., e.g. about 60 to about 70° C., e.g. 63-69° C. or 64-68° C.

Another reducing agent is di-iso-butylaluminium hydride (e.g. solution in toluene), in which case: a suitable solvent is dichloromethane and/or toluene, and/or a suitable reaction temperature can be about 0° C.
Compounds of formula (XIV), wherein R¹, R²and R³and X⁷are as defined herein, may be prepared by reaction of a compound of formula (XV) with an amine of formula R³NH₂, for example generally according to the method described by Yu et. al. in J. Med. Chem., 2001, 44, 1025-1027. The reaction is preferably carried out in the presence of a base such as triethylamine or N,N-diisopropylethylamine, and/or in an organic solvent such as ethanol, dioxane, 1-methyl-2-pyrrolidinone (NMP) or acetonitrile. The reaction may require heating e.g. to ca. 60-180° C., for example at 115° C.:
When R³is the N-aminocarbonyl-piperidinyl or N-aminocarbonyl-pyrrolidinyl group within sub-formula (bb) or (aa), that is wherein NHR³is of sub-formula (k2) or (k3), the compound of formula (XIV) can be prepared by reacting a compound of formula (XIVa), wherein R¹, R²and X⁷are as defined herein and n³=0 or 1, or a salt thereof (e.g. a hydrochloride salt thereof) with a urea-forming reagent capable of converting the (4-piperidinyl)amino or (3-pyrrolidinyl)amino group in the compound of formula (XIVa) into a [(1-aminocarbonyl)-4-piperidinyl]amino group or [(1-aminocarbonyl)-3-pyrrolidinyl]amino group as in the below-illustrated embodiment of formula (XIV) respectively:
The urea-forming reagent may be benzyl isocyanate (followed later by debenzylation e.g. reductive debenzylation), or preferably the urea-forming reagent is a tri(C_1-4alkyl)silyl isocyanate such as a tri(C_1-2alkyl)silyl isocyanate, preferably trimethylsilyl isocyanate. The conversion of the compound (XIVa) or salt thereof to the compound (XIV) is in one embodiment carried out in the presence of a suitable base such as N,N-diisopropylethylamine, in a suitable solvent such as dichloromethane or chloroform, at a suitable temperature such as at room temperature or at the reflux temperature of the solvent.
Compound (XIVa), wherein R¹, R², X⁷and n³are as defined herein, or a salt thereof, can be prepared from compound (XIVb), wherein R¹, R², X⁷and n³are as defined herein and Prot is a nitrogen protecting group such as (tert-butyloxy)carbonyl, by removal of the nitrogen protecting group. For example, removal of the (tert-butyloxy)carbonyl group can be effected under suitable acidic conditions, such as with hydrogen chloride (e.g. 4M) in a suitable solvent such as 1,4-dioxane:
Compound (XIVb), wherein R¹, R², and n³are as defined herein, X⁷is ethyl and Prot is (tert-butyloxy)carbonyl, can be prepared by reaction of a compound of formula (XV), wherein R¹and R²are as defined herein and X⁷=ethyl, with 1,1-dimethylethyl 4-amino-1-piperidinecarboxylate (e.g. commercially available from AstaTech, Philadelphia, USA) or 1,1-dimethylethyl 3-amino-1-pyrrolidinecarboxylate (e.g. commercially available from Aldrich). The reaction is optionally carried out in the presence of a base such as triethylamine or N,N-diisopropylethylamine, optionally in a suitable organic solvent such as acetonitrile, at a suitable temperature such as 60-100° C. (e.g. 80-90° C.):
Compounds of formula (XV), wherein R¹, R², and X⁷are as defined herein can be prepared by reaction of compounds of formula (XVI), wherein R¹is as defined herein, with a dialkyl (1-chloroalkylidene)propanedioate of formula (XVII) (which is (R²)(Cl)C═C(CO₂X⁷)₂, wherein R²and X⁷are as defined herein; for example a diethyl (1-chloroalkylidene)propanedioate for when X⁷is Et; and e.g. R²can be Et), followed by reaction with phosphorous oxychloride (POCl₃). Suitable conditions for reaction of compounds of formula (XVI) with a dialkyl (1-chloroalkylidene)propanedioate of formula (XVII) include heating, for example in a suitable solvent such as toluene, and for example in the presence of a suitable base such as triethylamine, e.g. at a suitable temperature such as the reflux temperature of the solvent. Suitable conditions for the reaction of the intermediate [formed from (XVI) and the dialkyl (1-chloroalkylidene)propanedioate (XVIII)] with phosphorous oxychloride (POCl₃) can include heating, e.g. heating at the reflux temperature of phosphorous oxychloride.
In one embodiment, a compound of formula (XVII), wherein R²and X⁷are as defined herein, is prepared by reaction of a compound of formula (XVIII), wherein R²and X⁷are as defined herein, with phosphorus oxychloride (POCl₃) in the presence of a suitable base such as tributylamine, at a suitable temperature such as ca. 80-130° C., for example ca. 100-120° C.
In one embodiment, a compound of formula (XVIII), wherein R²and X⁷are as defined herein, is prepared by reaction of a dialkyl malonate of formula (XIX), wherein X⁷is as defined herein, with magnesium chloride (suitably anhydrous) and a suitable non-aqueous base such as triethylamine, in a suitable solvent (e.g. anhydrous solvent) such as acetonitrile, at a suitable temperature such as ca. 5-10° C., followed by addition of an acid chloride of formula (XX), for example propanoyl chloride when R²is ethyl, at a suitable temperature such as between 10° C. and room temperature. In one embodiment, the reaction is for example carried out under anhydrous conditions:
Generally, many of the compounds of formulae (XIX) and (XX) are either known compounds or may be prepared e.g. by conventional means. For example, the compound of formula (XIX) where X⁷is ethyl, and the compound of formula (XX) where R²represents methyl or ethyl, are commercially available, e.g. from Aldrich or elsewhere.
For examples of syntheses of compounds (XVIII) and compounds (XVII), in which R²is cyclopropyl, n-propyl, ethyl, cyclobutyl and (cyclopropyl)methyl-, see for example Intermediates 1, 3 to 6 and 7 to 11 on pages 60-62 of WO 2005/090348 A1 (Glaxo Group Limited).
In an alternative embodiment, a compound of formula (XV), wherein R¹, R²and X⁷are as defined herein, is prepared by reaction of a compound of formula (XVI), wherein R¹is as defined herein, with a compound of formula (XXI), wherein R²and X⁷are as defined herein, with heating, followed by reaction with phosphorous oxychloride, again with heating (e.g. see Yu et. al. in J. Med. Chem., 2001, 44, 1025-1027). Compounds of formula (XXI) can for example be diethyl [(ethyloxy)methylidene]propanedioate (wherein R²is H and X⁷is Et, available from Aldrich) or diethyl [1-(ethyloxy)ethylidene]propanedioate (wherein R²is Me and X⁷is Et, see Eur. Pat. Appl. (1991), EP 413918 A2).
Where the desired amino pyrazole of formula (XVI) is not commercially available, in one alternative embodiment, a method of preparation of (XVI) comprises reaction of 3-hydrazinopropanenitrile (available from Lancaster Synthesis) with a suitable aldehyde of formula R⁴⁰CHO in a suitable solvent such as ethanol, with heating, followed by reduction with, for example sodium in a suitable solvent such as t-butanol. R⁴⁰should be chosen so as to contain one less carbon atom than R¹, for example R⁴⁰=methyl will afford R¹=ethyl. See also the method(s) described by Dorgan et. al. in J. Chem. Soc., Perkin Trans. 1, 1980, (4), 938-942:
In an alternative less-preferred embodiment of Process 1A, the 4-chloro substituent in the compound of formula (XV) is replaced by another halogen atom, such as a bromine atom, or by another suitable leaving group which is displaceable by an amine of formula R³NH₂. The leaving group can, for example, be a straight-chain alkoxy group —OR³⁵being —OMe, —OEt or —OPrⁿ, or a group
—O—S(O)₂—R³⁷, wherein R³⁷is methyl, CF₃, or phenyl or 4-methyl-phenyl. The reaction is optionally carried out with or without solvent. The reaction may require heating.
In one embodiment, a compound of formula (XI), wherein R¹and R²are as defined herein and R³represents the N-aminocarbonyl-piperidinyl or N-aminocarbonyl-pyrrolidinyl group of sub-formula (bb) or (aa), e.g. wherein NHR³is of sub-formula (k2) or (k3), is alternatively prepared from a compound of formula (XXXVIII), wherein R¹and R²are as defined herein, n³is 0 or 1, and Prot represents a suitable nitrogen protecting group such as tert-butoxycarbonyl. Conditions can include:

- suitable acidic conditions (for N-deprotection) such as hydrogen chloride in a suitable solvent such as 1,4-dioxane at a suitable temperature such as room temperature, followed by
- reacting the resultant N-deprotected piperidine/pyrrolidine with a urea-forming reagent (e.g. trimethylsilyl isocyanate) so as to convert the (4-piperidinyl)amino or (3-pyrrolidinyl)amino group in the compound into a [(1-aminocarbonyl)-4-piperidinyl]amino group or [(1-aminocarbonyl)-3-pyrrolidinyl]amino group in the below-illustrated embodiment of formula (XI) respectively [optional urea-forming conditions can include: carrying out the reaction in the presence of a suitable base such as N,N-diisopropylethylamine, in a suitable solvent such as dichloromethane or chloroform, at a suitable temperature such as at room temperature or at the reflux temperature of the solvent.].

In one embodiment, a compound of formula (XXXVIII), wherein R¹and R², n³and Prot are as defined herein, is prepared from a compound of formula (XXXIX), wherein R¹and R², n³and Prot are as defined herein. Conditions can include reaction of a compound of formula (XXXIX) with an azide such as sodium azide and a halogenating agent such as carbon tetrabromide, in the presence of a suitable phosphine such as triphenylphosphine, in a suitable solvent such as N,N,-dimethylformamide, at a suitable temperature such as between 0° C. and room temperature.
In one embodiment, a compound of formula (XXXIX), wherein R¹and R², n³and Prot are as defined herein, is prepared from a compound of formula (XL), wherein R¹and R², n³Prot and X⁷are as defined herein, by reduction with a suitable reducing agent such as lithium borohydride, in a suitable solvent such as a mixture of tetrahydrofuran and methanol, at a suitable temperature such as at the reflux temperature of the solvent.
In one embodiment, a compound of formula (XL), wherein R¹and R², n³Prot and X⁷are as defined herein, is prepared from compounds of formula (XV), wherein R¹, R², and X⁷are as defined herein, by reaction of a compound of formula (XV) with an amine of formula (XLI), wherein Prot and n³are as defined herein. The reaction is optionally carried out in the presence of a base such as triethylamine or N,N-diisopropylethylamine, and/or in an organic solvent such as ethanol, dioxane, 1-methyl-2-pyrrolidinone (NMP) or acetonitrile. The reaction may require heating e.g. to ca. 60-180° C., for example at 120° C.:

Process 1A

Alternative Embodiment 1A1

As an alternative embodiment within Process 1A, as the penultimate step, compounds of formula (III), wherein R¹, R², R³, R⁴, n and X¹are as defined herein, may also be prepared by reaction between compounds of formula (IX), wherein R¹, R², R³and R⁴are as defined herein, and compounds of formula (XXVI), wherein X¹and n are as described herein and X⁹is a suitable leaving group, preferably a halogen atom such as a chlorine atom; suitable conditions include stirring in a suitable anhydrous solvent such as dichloromethane, in the presence of a base such as triethylamine, at a suitable temperature such as between 0° C. and room temperature, for example between 0° C. and 10° C.
Compounds of formula (XXVI), wherein X¹, n and X⁹are as described herein, may be prepared from carboxylic acids of formula (XXVII), wherein X¹and n are as described herein, by treatment with a suitable activating agent such as thionyl chloride, phosphoryl chloride or other reagents as described in R. C. Larock, Comprehensive Organic Transformations, Wiley, 2^ndEd., 1999. For example when X⁹is chlorine compounds of formula (XXVI) may be prepared from compounds of formula (XXVII) by heating with thionyl chloride at a suitable temperature such as 100° C.
Compounds of formula (XXVII), wherein X¹and n are as described herein, may be prepared by hydrolysis of compounds of formula (XXV), wherein X¹, n and X⁸are as described herein. Preferably X⁸is tert-butyl and the formation of compounds of formula (XXVII) from compounds of formula (XXV) can be achieved by treatment with a suitable acid such as 4M hydrogen chloride in a suitable solvent such as 1,4-dioxane, at a suitable temperature such as room temperature.
Compounds of formula (XXV) may be prepared e.g. as may be described herein.

Process 1B

In the embodiment which is “Process 1B”, a compound of formula (II) or a salt thereof, wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein (in particular when R⁴is a hydrogen atom), is prepared by reaction of a compound of formula (IX) or a salt thereof (e.g. a HCl salt thereof, e.g. monohydrochloride salt thereof), wherein R¹, R², R³and R⁴are as defined herein (in particular when R⁴is a hydrogen atom), with a compound of formula (XXII) or a salt thereof, wherein R⁵, R⁶and n are as defined herein and X⁴is a suitable leaving group (e.g. wherein X⁴is as described hereinbelow). [As described above, a compound of formula (II) is a compound of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), Q¹is NH, Q²is —C(O)—, and L is (CH₂)_n.]
For various processes for the preparation of an amine compound of formula (IX) or a salt thereof (e.g. a HCl salt thereof, in particular for when R⁴is a hydrogen atom, and for processes for the preparation of the precursor intermediates usable to prepare the amine (IX) or a salt thereof, see the processes already extensively disclosed under the heading “Process 1A” hereinabove.
The compound of formula (XXII) or salt thereof can for example be a suitable activated carboxylic acid derivative wherein the leaving group X⁴is the leaving group of said activated carboxylic acid derivative. In the case of this activated carboxylic acid derivative, the leaving group X⁴can for example be of sub-formula (bt):
In the case of this activated carboxylic acid derivative, the leaving group X⁴can alternatively be for example —O—C(NHR′)═N—R″ or —O—C(NHR″)═N—R′, wherein R′ and R″ are the substituents (which may be the same or different) of an organic (di-substituted) carbodiimide reagent R′—N═C═N—R″ which may have been used to prepare (XXII) or a salt thereof from the corresponding carboxylic acid.
The leaving group X⁴can alternatively be, for example, a chlorine atom (CI), a bromine atom (Br), 1-imidazolyl, ort-Bu-C(O)—O—.
Preferably, the compound of formula (XXII) or the salt thereof (for example the suitable activated carboxylic acid derivative) is not isolated. Preferably, it is reacted with the amine of formula (IX) or the salt thereof to prepare the compound of formula (II) or the salt thereof, directly after formation of the compound of formula (XXII) or the salt thereof and without isolation of said compound (XXII) or salt.
A compound of formula (XXII), wherein R⁵, R⁶, n and X⁴are as defined herein, or a salt thereof can be formed from a carboxylic acid of formula (XXIII) or a salt (e.g. acid addition salt such as a HCl salt) thereof, wherein R⁵, R⁶, and n are as defined herein.
In one embodiment, a compound of formula (XXII) or a salt thereof, wherein the leaving group X⁴is of sub-formula (bt), is prepared from the corresponding carboxylic acid of formula (XXIII) or a salt thereof by the following reaction (a). In this reaction (a), the carboxylic acid (XXIII) or salt is reacted with a suitable organic carbodiimide e.g. organic di-substituted carbodiimide, such as 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide [also named 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide] or a salt thereof such as a hydrochloride salt thereof (EDC), or such as N,N′-dicyclohexylcarbodiimide (DCC), followed by reaction of the resulting product with 1-hydroxybenzotriazole (when X₅is CH) or 1-hydroxy-7-azabenzotriazole (when X₅is N).
In an alternative embodiment, a compound of formula (XXII) or a salt thereof, wherein the leaving group X⁴is of sub-formula (bt), is prepared from the corresponding carboxylic acid of formula (XXIII) or a salt thereof by the following reaction (b). In this reaction (b), the carboxylic acid (XXIII) or salt is reacted with a suitable 1-hydroxybenzotriazole-based or 1-hydroxy-7-azabenzotriazole-based coupling agent, such as (i), (ii), (iii) or (iv):
(i) O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (also called HBTU, when X₂is CH), or
(ii) 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU, when X₂is CH), or
(iii) O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU, when X₂is N), or
(iv) (benzotriazol-1-yloxy)-trispyrrolidinophosphonium hexafluorophosphate (PyBOP, when X₂is CH).
In one embodiment, this reaction (b) is carried out in the presence of a base e.g. a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA), and/or usually in the presence of a solvent such as an aprotic organic solvent (e.g. anhydrous solvent) such as N,N-dimethylformamide or acetonitrile, e.g. under anhydrous conditions and/or at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.).
Reaction (a) of the carboxylic acid (XXIII) or a salt thereof with the suitable organic carbodiimide (e.g. DCC; or more preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or a salt thereof such as a hydrochloride salt thereof) to prepare compound (XXII) or a salt thereof, in particular in the presence of 1-hydroxybenzotriazole, followed by reaction of the resulting compound (XXII) or the salt thereof with the amine of formula (IX) or the salt thereof, can be carried out as follows:

- in the presence of a suitable organic solvent (preferably anhydrous or at least substantially dry), such as one or more C_1-7alkyl alcohols (in particular one or more C_4-6alkyl alcohols, such as pentanol, e.g. pentan-1-ol or pentan-2-ol, or butanol, e.g. butan-2-ol or butan-1-ol, or hexanol e.g. hexan-1-ol), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, 1-methyl-2-pyrrolidinone (NM P), acetonitrile, tetrahydrofuran (e.g. anhydrous), dichloromethane, or a mixture of any of these (e.g. N,N-dimethylacetamide and pentan-1-ol, or NMP and pentan-1-ol); and/or
- at a suitable temperature such as about room temperature (e.g. about 15 to about 25° C., or about 18 to about 25° C.); and/or
- under an inert atmosphere such as nitrogen; and/or
- in the presence of a non-aqueous base such as solid potassium carbonate (e.g. having about 325 mesh particle size), solid sodium carbonate, or a non-aqueous tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA) or triethylamine; and/or
- using an aqueous alkaline (e.g. concentrated aqueous alkaline) extraction of a or the organic phase (e.g. using conc. aq. NaOH or conc. aq. KOH), after the reaction which has prepared compound (II) or a salt thereof [this extraction may help to decrease the amount of certain possible reaction byproducts (e.g. ester byproducts, e.g. when the solvent comprises an alcohol and/or when the starting material compound (XXII) or (XXIII) or a salt thereof contains an alcoholic OH group in the R⁵and/or R⁶group) that might perhaps be formed during preparation of the product (II) or the salt thereof].

Reaction (a) of the carboxylic acid (XXIII) or a salt thereof with the suitable organic carbodiimide (e.g. DCC; or more preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or a salt thereof such as a hydrochloride salt thereof) to prepare the compound (XXII) or a salt thereof, in particular in the presence of 1-hydroxybenzotriazole, followed by reaction of the resulting compound (XXII) or the salt thereof with the amine of formula (IX) or the salt thereof, can be in particular carried out:

- in the presence of a hydrochloride salt (eg monohydrochloride) (e.g. solid e.g. crystalline) of an amine compound of formula (IX); and/or
- in the presence of a suitable organic solvent (preferably anhydrous or at least substantially dry) being or comprising an organic solvent with low water-miscibility such as one or more C_4-6alkyl alcohols (such as pentanol, e.g. pentan-1-ol or pentan-2-ol, or butanol, e.g. butan-2-ol or butan-1-ol, or hexanol e.g. hexan-1-ol) (e.g. to allow aqueous extractions more easily, e.g. see below); and/or
- at a suitable temperature such as about room temperature (e.g. about 15 to about 25° C., or about 18 to about 25° C.); and/or
- under an inert atmosphere such as nitrogen; and/or
- in the presence of a non-aqueous inorganic base such as solid potassium carbonate (e.g. having about 325 mesh particle size) or solid sodium carbonate, and for a solid base preferably with rapid stirring (e.g. about 160 rpm); and/or
- using an aqueous alkaline (e.g. concentrated aqueous alkaline) extraction of a or the organic phase (e.g. using conc. aq. NaOH or conc. aq. KOH), after the reaction which has prepared compound (II) or a salt thereof [this extraction may help to decrease the amount of certain possible reaction byproducts (e.g. ester byproducts, e.g. when the solvent comprises an alcohol and/or due to the starting material compound (XXII) or (XXIII) or the salt thereof generally containing a 2-hydroxyethyl group) that might perhaps be formed]; and/or
- using an aqueous acidic extraction of a or the organic phase (e.g. using aq. HCl) after the reaction to prepare (II) or a salt thereof, and optionally after an aqueous alkaline extraction which may be present, with the amount of aqueous acid used in the acid extraction being such that the pH of the aqueous phase is adjusted to pH 5.75±0.25.

Where a salt of the compound of formula (II) (or (I)) is prepared, in one embodiment this is salt optionally prepared after the preparation of the compound (II) or (I) and without isolation of said compound, e.g. by crystallisation of the salt directly from essentially the same or similar organic solvent as that used in the reaction to prepare the compound (II) or (I) (e.g. the organic solvent can be one or more C_4-6alkyl alcohols, such as pentanol e.g. pentan-1-ol), e.g. by salt crystallisation from the reaction mixture. In one embodiment, this salt crystallisation is optionally done:
(i) by conversion if necessary of the compound (II) or (I) and/or the salt thereof, prepared from the reaction and/or extraction thereof, into substantially wholly the “free base” form, e.g. by aqueous alkaline extraction of the non-extracted or previously-extracted reaction mixture; and/or
(ii) by optional reduction of the volume of and/or heating of the reaction solvent, if necessary or desirable, e.g. after preparation of compound (II) or (I) and after aqueous extraction of the reaction mixture, and/or
(iii) by mixing an appropriate amount of an appropriate acid such as HCl with the reaction mixture (e.g. ca. 1 mole equivalent of HCl to prepare a monohydrochloride salt, e.g. using 2-10M aq. HCl, e.g. 4-6 M aq. HCl); and/or
(iv) by optional mixing with the reaction solvent of an organic “antisolvent” capable of crystallising the salt of the compound (II) or (I) from the organic solvent-antisolvent mixture, typically followed by cooling of the mixture and/or isolation eg by filtration of the crystallised salt. In particular, depending on the solubility properties of the salt of the compound, tert-butyl methyl ether (TBME) is optionally used as such an antisolvent.
In one alternative embodiment of when the compound of formula (XXII) or salt is a suitable activated carboxylic acid derivative, the compound of formula (XXII) or a salt thereof is the product (adduct) formed from the reaction of the carboxylic acid of formula (XXII) or salt thereof with a suitable organic carbodiimide e.g. organic di-substituted carbodiimide (e.g. R′—N═C═N—R″) [e.g. wherein the carbodiimide can be 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or a salt thereof such as a hydrochloride salt thereof (EDC), or N,N′-dicyclohexylcarbodiimide (DCC)]. In this case, in the compound of formula (XXII) or salt which is the carboxylic acid-carbodiimide adduct, the leaving group X⁴is —O—C(NHR′)═N—R″ or —O—C(NHR″)═N—R′, wherein R′ and R″ are the substituents (which may be the same or different) of the organic (di-substituted) carbodiimide reagent used. This is the situation for example when the carbodiimide is reacted with the carboxylic acid (XXIII) or a salt thereof without 1-hydroxybenzotriazole or 1-hydroxy-7-azabenzotriazole being present. In one embodiment, this reaction is carried out in a suitable organic solvent e.g. an aprotic organic solvent (preferably anhydrous) such as N,N-dimethylformamide or acetonitrile, e.g. under anhydrous conditions and/or e.g. at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.). In one optional embodiment, this reaction is carried out in the presence of a tertiary amine base such as N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA).
In another alternative embodiment, the compound of formula (XXII) or salt thereof is for example the acid chloride (in which case, the leaving group X⁴is a chlorine atom (Cl)). In one embodiment, this acid chloride is for example prepared from the corresponding carboxylic acid (XXIII) or a salt thereof by reaction with oxalyl chloride, usually in a suitable organic solvent (e.g. anhydrous) such as DMF or dichloromethane (e.g. dichloromethane or another solvent together with a catalytic amount of DMF), and/or e.g. under anhydrous conditions, and/or e.g. at room temperature or at or below 20° C. When an acid chloride of formula (XXII) wherein X⁴is Cl, or a salt thereof, is used to prepare the compound of formula (II) or (I), the reaction with amine (IX) or a salt thereof is usually carried out in the presence of a tertiary amine base such as N,N′-diisopropylethylamine (ⁱPr₂NEt=DIPEA) and/or in a suitable aprotic organic solvent (e.g. anhydrous solvent) such as acetonitrile or dichloromethane, for example at room temperature (e.g. about 18 to about 25° C.).
In the compound (XXII) or a salt thereof, further alternative values of the leaving group X⁴include a bromine atom (Br), 1-imidazolyl (e.g. as prepared from the acid (XXIII) or salt using carbonyl diimidazole), and t-Bu-C(O)—O— (e.g. as prepared from the acid (XXIII) or salt using t-Bu-C(O)—Cl).
Compounds of formula (XXIII), wherein R⁵, R⁶and n are as defined herein, can for example typically be formed by hydrolysis of esters of formula (XXIV), wherein R⁵, R⁶, and n are as defined herein and X⁸is an alkyl group, such as ethyl or preferably tert-butyl. The hydrolysis may be achieved under suitable conditions, such as by reaction with 4M hydrogen chloride in 1,4-dioxane (e.g. for when X⁸is tert-butyl but usually not when X⁸is ethyl), at a suitable temperature such as room temperature, optionally in dry dichloromethane.
Compounds of formula (XXIV), wherein R⁵, R⁶n and X⁸are as defined herein, can for example typically be formed by substitution of compounds of formula (XXV), wherein X⁸and n are as defined herein and X¹is a leaving group as defined herein (e.g. for X¹as defined in Process 1A hereinabove, e.g. X¹can be a bromine atom), with an amine of formula (IV), wherein R⁵and R⁶are as defined herein, optionally in the presence of a suitable base such as N,N-diisopropylethylamine, in a suitable solvent such as N,N-dimethylformamide, at a suitable temperature such as between room temperature and 100° C., for example at about 60° C.
Compounds of formula (XXV), wherein X⁸and X¹and n are as defined herein, can for example typically be formed from compounds of formula (XXVI), wherein X⁸is as defined herein, by reaction with a suitable acylating agent (VI), wherein X¹, X²and n are as defined herein e.g. hereinabove (e.g. for X¹and X²as defined in Process 1A hereinabove, e.g. X¹can be a bromine atom and/or X²can be a chlorine atom). Suitable conditions include carrying out the reaction in a suitable anhydrous solvent such as dichloromethane or chloroform, in the presence of a suitable non-aqueous base e.g. a tertiary amine base such as N,N-diisopropylethylamine or triethylamine, at a suitable temperature such as between 0° C. and room temperature, e.g. under anhydrous conditions.
At least some of the compounds of formula (XXVI) (if not commercially available or known in the literature) are likely to be capable of being prepared e.g. by conventional means e.g. from the corresponding carboxylic acid. For example, 2-aminonicotinic acid (2-aminopyridine-3-carboxylic acid) and 6-aminonicotinic acid (6-aminopyridine-3-carboxylic acid) are commercially available, for example from Aldrich and/or Fluka.

Process 1C

In Process 1C, a compound of formula (XLII), wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and wherein R^6′ is C_1-4alkyl substituted by one OH substituent (e.g. wherein R^6′ is —CH₂CH₂OH, —CH₂CH(Me)OH, —CH₂CH₂CH₂OH, or —CH₂CH₂CH₂CH₂OH, in particular wherein R^6′ is —CH₂CH₂OH), which is one embodiment of a compound of formula (I), or a salt thereof, is prepared by deprotection of a compound of formula (XLIII) or a salt thereof, wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), wherein R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and wherein R^6-protis C_1-4alkyl substituted by one protected OH substituent O-Prot′ (e.g. wherein R^6-protis —CH₂CH₂—O-Prot′, —CH₂CH(Me)-O-Prot′, —CH₂CH₂CH₂—O-Prot′, or —CH₂CH₂CH₂CH₂—O-Prot′, in particular wherein R^6-protis —CH₂CH₂—O-Prot′).
For example, O-Prot′ can be any protected OH group which is deprotectable by treatment with acid or base or fluoride ions. In particular, O-Prot′ can be —OC(O)—C_1-6alkyl such as OAc (acetate), OC(O)—CF₃, —OC(O)aryl such as —OC(O)-phenyl, or —O-(tri-organo)silyl such as O-trialkylsilyl such as O-TBDMS (tert-butyldimethylsilyloxy) or O-TMS (trimethylsilyloxy).
Deprotection of the compound of formula (XLI II) or the salt thereof can be via standard OH-deprotection conditions, e.g. using acid or more preferably base in particular strong base such as strong inorganic base (e.g. NaOH or KOH, e.g. aqueous and/or ethanolic NaOH or KOH, in particular concentrated (e.g. 5-12M or 10-11M) aqueous NaOH or KOH) for deprotection where O-Prot′ is —OC(O)—C_1-6alkyl such as OAc (acetate) or —OC(O)—CF₃or —OC(O)aryl. Deprotection mediated by base, e.g. where O-Prot′ is —OC(O)—C_1-6alkyl or —OC(O)—CF₃or —OC(O)aryl, can in particular be carried out under heating (e.g. at ca. 40-60° C. such as ca. 50° C.) and/or in the presence of an organic solvent such as a C_1-7alcohol for example a C_4-6alcohol e.g. pentanol such as pentan-1-ol. Where O-Prot′ is O-trialkylsilyl such as O-TBDMS or O-TMS, this can be deprotected sometimes by acid or more usually by fluoride ions such as by use of tetra-n-butylammonium fluoride. For other OH-protecting groups and their chemistry, see Theadora Green, “Protective Groups in Organic Synthesis”.
Compounds of formula (XLIII) or salts thereof can typically be formed by the following reaction of an amide of formula (XLV) or a salt thereof, wherein R⁴and n are as defined herein (in particular wherein R⁴is a hydrogen atom), R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and R^6-protis as defined herein, with a compound of formula (XLIV) or an acid addition salt thereof (e.g. a sulfonate salt thereof, e.g. methanesulfonate or benzenesulfonate salt of (XLIV)), wherein X¹¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenenesulfonate), triflate (trifluoromethanesulfonate), or a chlorine, bromine or iodine atom (in particular a chlorine atom). Compounds of formula (XLIV), where X¹¹is mesylate, tosylate, triflate, or a chlorine, bromine or iodine atom, are generally thought to be potent electrophiles.
Conditions can include heating compound (XLIV) or the acid addition salt thereof (e.g. a sulfonate salt thereof, e.g. methanesulfonate or benzenesulfonate salt of (XLIV)) and compound (XLV) or a salt thereof together, e.g. at ca. 50-100° C. or ca. 60-80° C., e.g. at ca. 60° C., for example in a suitable solvent, such as N-methyl-2-pyrrolidinone (that is 1-methyl-2-pyrrolidinone, also called NMP), dimethyl sulfoxide, ethyl acetate, n-propyl acetate, chloroform, diethylene glycol dimethyl ether [“diglyme”, (CH₃OCH₂CH₂)₂O], N,N-dimethylformamide (DMF), tetrahydrofuran (THF), or mixtures thereof. Suitably, the solvent can be NMP, dimethyl sulfoxide, ethyl acetate, n-propyl acetate, chloroform, diethylene glycol dimethyl ether, or mixtures thereof. Preferably, the solvent is 1-methyl-2-pyrrolidinone (NMP).
Due to its reactivity, the compound of formula (XLIV) or the acid addition salt thereof (e.g. sulfonate salt thereof, e.g. methanesulfonate or benzenesulfonate salt of (XLIV)), wherein X¹¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenenesulfonate), triflate (trifluoromethanesulfonate), or a chlorine, bromine or iodine atom (in particular a chlorine atom), is preferably not isolated; e.g. it can be prepared in solution and used directly in solution (with or without partial or full solvent replacement), e.g. by being used in THF and/or NMP solution, in the next step (i.e. reaction with the amide of formula (XLV) or the salt thereof).
The compound of formula (XLIV) or the acid addition salt thereof can for example be prepared as described in Process 1A herein. However, when X¹¹is Cl, see the detailed scheme below marked “Scheme—Process 1C example”, for some modified processes/reagents/reaction conditions leading to an acid addition salt (e.g. methanesulfonate salt) of the compound of formula (XLIV) wherein R¹and R²are both ethyl, R³is tetrahydro-2H-pyran-4-yl, and X¹¹is Cl. See in particular Stages 1c, 1d, 2a, and 2b within that Scheme for alternative reagents and/or reaction conditions. For specific examples of these modified processes/reagents/reaction conditions, see Intermediate 2B (for Stage 1c preparation), Intermediate 2C (for Stage 1d preparation), Intermediate 3 (alternative preparation) (for Stage 2a preparation), and Intermediate 4 (alternative preparation) (for Stage 2b preparation) as disclosed herein.
One illustrative example of a specific route within Process 1C, e.g. for the preparation of the compound whose formula is,
or a salt thereof, is illustrated in “Scheme—Process 1C example” as follows:
The final deprotection step in the specific route [“Scheme—Process 1C example”] shown above can for example involve:
(i) extracting the acetyl-O-protected product within formula (XLIII) into n-pentanol (pentan-1-ol);
(ii) adding aqueous NaOH solution (e.g. ca. 2M to ca. 10M such as ca. 10M), optionally with heating e.g. at ca. 40-60° C. such as ca. 50° C., to cleave the acetate protecting group; and
(iii) removing the aqueous phase (optionally after addition of water); and
(iv) isolating the product OH-containing compound from the pentan-1-ol phase.
As part of the general preparation of compounds of formula (XLII) or salts thereof, a compound of formula (XLV) or a salt thereof can for example be prepared by the following generalised route:
Typical conditions and/or reagents for the protection of the OH group within R^6′ of compound (XLVI) or a salt thereof, to form (XLV) or a salt thereof, can include conditions suitable for OH-protection with the OH-protecting group used. For example, where O-Prot′ (within R^6-protof compound (XLV)) is OAc (acetate), acetic anhydride can be used, e.g. in a suitable solvent (e.g. anhydrous) such as acetonitrile, and/or in the presence of an organic base such as triethylamine, and/or e.g. with heating such as at ca. 60-90° C., for example heating at ca. 60° C. or ca. 81-82° C. e.g. with acetonitrile solvent. Alternatively, acetyl chloride can be used for acetyl OH-protection. For other OH-protecting groups and their chemistry, see Theadora Green, “Protective Groups in Organic Synthesis”.
Conditions and/or reagents for the coupling of the compound (XLVII) or a salt thereof with the amine R^5′R^6′NH or a salt thereof to prepare compound (XLVI) or a salt thereof can include:

- using at least 2 equivalents (e.g. 3-10 equivalents, preferably 5-10 equivalents, such as 6-9 equivalents, e.g. ca. 7 equivalents) of the amine R^5′R^6′NH [or if not then using another non-nucleophilic organic or inorganic base to remove the HBr formed in the reaction, such as pyridine, 2,6-dimethylpyridine, tri-n-butylamine, N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA), or DABCO, or K₂CO₃or Na₂CO₃], and/or
- using a suitable dipolar aprotic solvent such as dimethylsulfoxide, NMP, DMF, or dichloromethane (in particular dimethylsulfoxide), and/or
- either heating e.g. at ca. 40-80° C. or ca. 50-80° C. e.g. at ca. 60° C., or carrying out the reaction at room temperature.

Conditions and/or reagents for the coupling of the compound (XLVIII) or a salt thereof with the specific acid chloride compound within formula (VI) will normally include generally anhydrous/dry conditions. and/or can optionally include:

- using a suitable organic or inorganic non-nucleophilic base such as pyridine, 2,6-dimethylpyridine, tri-n-butylamine, N,N-diisopropylethylamine (ⁱPr₂NEt=DIPEA), or DABCO, or K₂CO₃or Na₂CO₃(in particular tri-n-butylamine or pyridine), and/or
- using a suitable solvent (e.g. generally dry) such as a C_4-6ketone, a C_2-4alkyl acetate, C_1-3alkyl-CN, dichloromethane, chloroform, tetrahydrofuran or toluene; in particular 2-butanone (methyl ethyl ketone, MEK), pentanone such as 3-pentanone, n-propyl acetate, n-butyl acetate, acetonitrile, propionitrile (CH₃CH₂—CN), butyronitrile (CH₃CH₂CH₂—CN), dichloromethane, tetrahydrofuran or toluene; in particular 2-butanone or butyronitrile (CH₃CH₂CH₂—CN).

The compounds of formula (VI) wherein X¹is Br and X²is Cl can be obtained by the skilled man, for example using process(es) as described elsewhere herein.
One embodiment of the compound (XLVIII), 6-aminonicotinamide (6-aminopyridine-3-carboxamide), is commercially available e.g. from Aldrich and/or Fluka.

Process 1D

In Process 1D, in order to prepare a compound of formula (XLIIa), wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5″ and R^6″ are as defined herein for R⁵and R⁶respectively provided that there is no OH group in R^5″ or R^6″ or [R^5″ and R^6″ taken together] and provided that R⁸is not H, which is one embodiment of a compound of formula (I), or a salt thereof, an amide of formula (XLVa) or a salt thereof, wherein R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5″ and R^6″ are as defined herein for R⁵and R⁶respectively provided that there is no OH group in R^5″ or R^6″ or [R^5″ and R^6″ taken together] and provided that R⁸is not H, can be reacted with a compound of formula (XLIV) or an acid addition salt thereof (e.g. a sulfonate salt thereof e.g. methanesulfonate or benzenesulfonate salt thereof), wherein X¹¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenenesulfonate), triflate (trifluoromethanesulfonate), or a chlorine, bromine or iodine atom (in particular a chlorine atom):
Compounds of formula (XLVa) are optionally prepared by a process analogous to that of compound (XLV) or (XLVI) in Process 1C (e.g. see above), but without the OH-protection step.

Process 2A

(For example, see Examples 5, 7, 8, 13, 15 and 16).
Compounds of formula (XXVIII), which are compounds of formula (I) wherein Ar has sub-formula (w), Q³is a bond, and L is (CH₂)_n, wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, or salts thereof, may for example typically be prepared by reaction (by substitution) of compounds of formula (XXIX) or salts thereof, wherein R¹, R², R³, R⁴and n are as defined herein and X¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenesulfonate), or a halogen atom (preferably a halogen atom such as a bromine atom), with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions generally include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as about 70-90° C. e.g. about 80-85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (XXIX), wherein R¹, R², R³, R⁴, n and X¹are as defined herein, may be prepared from compounds of formula (IX), wherein R¹, R², R³and R⁴are as defined herein, by reaction with a suitable acylating agent of formula (VI) wherein X¹, X²and n are as defined herein. Suitable conditions generally include carrying out the reaction in a suitable anhydrous solvent such as dichloromethane or chloroform, and/or in the presence of a suitable base e.g. organic tertiary amine base such as N,N-diisopropylethylamine or triethylamine, e.g. at a suitable temperature such as between 0° C. and room temperature.
Compounds of formulae (IX) and (VI) may be prepared as described hereinabove in Process 1A.

Process 3

In general terms, the Process 3 can be as follows:
A compound of formula (XXXa), wherein R¹, R², R³, R⁴R⁵, R⁶, m¹, and m²are as defined herein (suitably, m¹and m²are both 4) [which is one embodiment of a compound of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d)], or a salt thereof, may typically be prepared by reaction by substitution of a compound of formula (XXXIa), or a salt thereof, wherein R¹, R², R³, R⁴, X¹, m¹, and m²are as defined herein, with an amine of formula (IV), or a salt thereof, wherein R⁵and R⁶are as defined herein. At least about 2 equivalents of the amine of formula (IV) or the salt thereof can be used. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
For the suitable embodiment wherein m¹and m²are both 4:
Compounds of formula (XXX), wherein R¹, R², R³, R⁴R⁵, and R⁶are as defined herein, or salts thereof, may typically be prepared by reaction by substitution of a compound of formula (XXXI), or a salt thereof, wherein R¹, R², R³, R⁴and X¹are as defined herein, with an amine of formula (IV), or a salt thereof wherein R⁵and R⁶are as defined herein. At least about 2 equivalents of the amine of formula (IV) or the salt thereof can be used. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (XXXI), wherein R¹, R², R³, R⁴and X¹are as defined herein, may typically be prepared by reaction between compounds of formula (IX), wherein R¹, R², R³and R⁴are as defined above, and compounds of formula (XXXIII) wherein X¹and X⁴are as defined herein (e.g. X¹can in particular be Br and/or X⁴can in particular be Cl).
Compounds of formula (XXXIII) wherein X⁴is a chlorine atom (Cl) (and optionally wherein X¹is Br) can e.g. be prepared as illustrated in Intermediates 26, 25, 24, 23, and/or 22 herein.
Alternatively, the activated compound (the compound of formula (XXXIII)) can for example be an activated carboxylic acid derivative wherein the leaving group X⁴is
The latter activated compound of formula (XXXIII) can be formed from the carboxylic acid of formula (XXXIV), wherein X¹is as defined above:
(a) by reaction of the carboxylic acid (XXXIV) with a suitable carbodiimide such as 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide [also named 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide], or a salt thereof e.g. hydrochloride salt,
preferably followed by reaction of the resulting product with 1-hydroxybenzotriazole, in a suitable solvent (preferably anhydrous) such as N,N-dimethylformamide or acetonitrile, e.g. at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.);
or:
(b) by reaction of the carboxylic acid (XXXIV) with 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate or O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate, e.g. in the presence of a base such as N,N-diisopropylethylamine, and/or usually in the presence of a solvent such as N,N-dimethylformamide or acetonitrile e.g. at a suitable temperature such as room temperature (e.g. about 18 to about 25° C.).
Compounds of formula (XXXIV), wherein X¹is as defined herein, may for example be prepared by hydrolysis of an ester of formula (XXXV), wherein X¹and X⁸are as defined herein. Conditions can include reaction with a base such as sodium hydroxide or potassium hydroxide in a suitable solvent such as aqueous ethanol or aqueous dioxane, or if X⁸is tert-butyl then 4M hydrogen chloride in dioxane can be used.
Compound of formula (XXXV), wherein X¹and X⁸are as defined herein, may for example be prepared by reacting compounds of formula (XXXVI), wherein X⁸is as defined herein (e.g. where X⁸=tert-butyl, can optionally be prepared according to Tetsuo Miwa et. al. J. Org. Chem. 1993, 58(7), 1696) with a suitable alkylating agent of formula (XXXVII), wherein X¹is as defined herein.
Compounds of formula (XXXVI) may for example typically be prepared according to the following scheme:

Process 4

Compounds of formula (XLII), wherein R¹, R², R³, R⁴, R⁵and R⁶are as defined herein, may typically be prepared by reaction by substitution of compounds of formula (XLIII) or a salt thereof, wherein R¹, R², R³, R⁴and X¹are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (XLIII), wherein R¹, R², R³, R⁴and X¹are as defined above, may for example be prepared from compounds of formula (XLIV), wherein R¹, R², R³and R⁴are as defined above. For example, when X¹represents a halogen atom such as a bromine atom, compounds of formula (XLIII) may be prepared from compounds of formula (XLIV) and a suitable halogenating agent such as carbon tetrabromide, in the presence of a suitable phosphine such as triphenylphosphine, in a suitable solvent such as dichloromethane, at a suitable temperature for example between 0° C. and room temperature.
Compounds of formula (XLIV), wherein R¹, R², R³and R⁴are as defined above, may for example be prepared from compounds of formula (IX), wherein R¹, R², R³and R⁴are as defined above, and the compound of formula (XLV), in the presence of a suitable amide coupling reagent such as (1H-1,2,3-benzotriazol-1-yloxy)(tri-1-pyrrolidinyl)phosphonium hexafluorophosphate (available from Aldrich) and a suitable base such as N,N-diisopropylethylamine, in a suitable solvent such as anhydrous N,N-dimethylformamide, at a suitable temperature such as room temperature.
The compound of formula (XLV) can optionally be prepared according to the following scheme:

Process 5

Compounds of formula (XLVI), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may typically be prepared by reaction by substitution of compounds of formula (XLVII) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C., e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (XLVII), wherein R¹, R², R³, R⁴, X¹and n are as defined herein, and with a 2,5-di-(carbonylamino) substitution pattern on the pyridine ring, may e.g. be prepared according to the following scheme:

Process 6

Compounds of formula (XLVIII), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may typically be prepared by reaction by substitution of compounds of formula (XLIX) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (XLIX), wherein R¹, R², R³, R⁴, X¹and n are as defined above, may for example be prepared according to the following scheme:

Process 7

Compounds of formula (L), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may typically be prepared by reaction by substitution of a compound of formula (LI) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (LI), wherein R¹, R², R³, R⁴, X¹and n are as defined above, may e.g. typically be prepared according to the following scheme:
Compounds of formula (V) may e.g. typically be prepared as described above.

Process 8

Compounds of formula (LII), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may typically be prepared by reaction by substitution of a compound of formula (LIII) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (LIII), wherein R¹, R², R³, R⁴, X¹and n are as defined above, may e.g. typically be prepared according to the following scheme:

Process 9

Compounds of formula (LIV), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may typically be prepared by reaction by substitution of a compound of formula (LV) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (LV) wherein R¹, R², R³, R⁴, X¹and n are as defined above, may e.g. typically be prepared according to the following scheme:
Note: In the above scheme:
(a) Oxone™ is potassium peroxymonosulphate, which is 2KHSO₅.KHSO₄.K₂SO₄;
(b) Pd₂(dba)₃is tris(dibenzylideneacetone)-dipalladium (0);
and (c) Xantphos is (9,9,-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine).
Compound of formula (IX) may e.g. typically be prepared as described above.

Process 10

Compounds of formula (LVI), wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, may e.g. typically be prepared by reaction by substitution of a compound of formula (LVII) or a salt thereof, wherein R¹, R², R³, R⁴, X¹and n are as defined herein, with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein. Suitable conditions include heating in a suitable solvent such as N,N-dimethylformamide, suitably in the presence of a suitable base e.g. an organic tertiary amine base such as N,N-diisopropylethylamine, e.g. at a suitable temperature such as ca. 60-100° C. e.g. ca. 85° C. Alternative conditions include heating under microwave irradiation in a suitable solvent such as N,N-dimethylformamide, e.g. at a suitable temperature such as ca. 140-150° C.
Compounds of formula (LVII) wherein R¹, R², R³, R⁴, X¹and n are as defined above, may e.g. typically be prepared according to the following scheme:
Compounds of formula (IX) may e.g. be prepared as described above.

Process 11

Compounds of formula (XIV) wherein R²represents fluoroalkyl (for example trifluoromethyl) may e.g. typically be prepared according to the following scheme, followed by appropriate subsequent steps, e.g. as described in Process 1A or 1B or 1C:

Process 12

Compounds of formula (IX) wherein R⁴represents methyl or ethyl may e.g. typically be prepared according to the following scheme, wherein R^4-C1represents H when R⁴is methyl and R^4-C1represents methyl when R⁴is ethyl; followed by appropriate subsequent steps, e.g. as described in Process 1A or 1B or 1C:

Process F

Conversion of One Compound of Formula (I), or a Salt Thereof into Another Compound of Formula (I) or a Salt Thereof

In optional Process F, one compound of formula (I) or salt thereof (or a protected version thereof, such as an N-protected version thereof e.g. BOC-N-protected or benzyloxycarbonyl-N-protected version; or a derivative thereof such as an ester derivative thereof) is optionally converted into another compound of formula (I) or a salt thereof. This conversion reaction can for example occur within the R³group. This conversion optionally comprises or is one or more of the following processes F1 to F10:
F1. Conversion of a ketone into the corresponding oxime.
F2. An oxidation process. For example, the oxidation process can comprise or be oxidation of an alcohol to a ketone (e.g. using Jones reagent) or oxidation of an alcohol or a ketone to a carboxylic acid.
F3. A reduction process, for example reduction of a ketone or a carboxylic acid to an alcohol.
F4. Acylation, for example acylation of an amine (e.g. see Examples 329-349 and Example 353 of WO 2004/024728 A2 for suitable process details), or acylation of a hydroxy group.
F5. Alkylation, for example alkylation of an amine or of a hydroxy group.
F6. Hydrolysis, e.g. hydrolysis of an ester to the corresponding carboxylic acid or salt thereof (e.g. see Examples 351, 488, 489, 650, 651 of WO 2004/024728 A2 for suitable process details).
F7. Deprotection, e.g. deprotection of (e.g. deacylation of, or t-butyloxycarbonyl (BOC) removal from, or benzyloxycarbonyl removal from) an amine group. BOC deprotection is usually carried out under acidic conditions e.g. using hydrogen chloride in an organic solvent such as dioxan. Benzyloxycarbonyl deprotection is optionally carried out by hydrogenation.
F8. Formation of an ester or amide, for example from the corresponding carboxylic acid.
and/or
F9. Beckmann rearrangement of one compound of formula (I) into another compound of formula (I), for example using cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) together with a formamide such as DMF, e.g. at room temperature (see L. D. Luca, J. Org. Chem., 2002, 67, 6272-6274). The Beckmann rearrangement can for example comprise conversion of a compound of formula (I) wherein NHR³is of sub-formula (o2)
into a compound of formula (I) wherein NHR³is of sub-formula
and process details can be for example as illustrated in Examples 658 and 659 of WO 2004/024728 A2.

Synthetic Process Summary

The present invention therefore also provides a process for preparing a compound of formula (I) or a salt (e.g. pharmaceutically acceptable salt) thereof:
wherein Ar has the sub-formula (w) or (y):
and wherein R¹, R², R³, R⁴, R⁵, R⁶, L, Q¹Q²and Q³are as defined herein, the process comprising:
(1A) to prepare a compound of formula (II), which are compounds of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), Q¹is NH, Q²is —C(O)—, and L is (CH₂)_n, wherein R¹, R², R³, R⁴, R⁵, R⁶, and n are as defined herein, or a salt thereof,

- reaction (substitution) of a compound of formula (III), wherein X¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenesulfonate) or a halogen atom (suitably a halogen atom, in particular a bromine atom), and R¹, R², R³, R⁴and n are as defined herein, with an amine of formula (IV), wherein R⁵and R⁶are as defined herein:

or
(1B) to prepare a compound of formula (II) or a salt thereof, wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein (in particular when R⁴is a hydrogen atom),

- reaction of a compound of formula (IX) or a salt thereof (e.g. a HCl salt thereof, e.g. monohydrochloride salt thereof), wherein R¹, R², R³and R⁴are as defined herein (in particular when R⁴is a hydrogen atom), with a compound of formula (XXII) or a salt thereof, wherein R⁵, R⁶and n are as defined herein and X⁴is a suitable leaving group (e.g. wherein X⁴is as described herein):

or
(1C) to prepare a compound of formula (XLII), wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and wherein R^6′ is C_1-4alkyl substituted by one OH substituent (in particular wherein R^6′ is —CH₂CH₂OH), which is one embodiment of a compound of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), or a salt thereof, by carrying out steps (1C)(i) and (1C)(ii):

- (1C)(i) formation of a compound of formula (XLIII) or a salt thereof, wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), wherein R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and wherein R^6-protis C_1-4alkyl substituted by one protected OH substituent O-Prot′ (in particular wherein R^6-protis —CH₂CH₂—O-Prot′), wherein O-Prot′ is any protected OH group which is deprotectable by treatment with acid or base or fluoride ions [in particular, —OC(O)—C_1-6alkyl such as OAc (acetate), OC(O)—CF₃, —OC(O)aryl such as —OC(O)-phenyl, or —O-(tri-organo)silyl such as O-trialkylsilyl such as O-TBDMS (tert-butyldimethylsilyloxy) or O-TMS (trimethylsilyloxy)],
- by reaction of an amide of formula (XLV) or a salt thereof, wherein R⁴and n are as defined herein (in particular wherein R⁴is a hydrogen atom), R^5′ is a hydrogen atom (H), methyl, ethyl, n-propyl, or isopropyl (e.g. methyl), and R^6-protis as defined herein, with a compound of formula (XLIV) or an acid addition salt thereof (e.g. a sulfonate salt thereof e.g. methanesulfonate or benzenesulfonate salt thereof), wherein X¹¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenenesulfonate), triflate (trifluoromethanesulfonate), or a chlorine, bromine or iodine atom (in particular a chlorine atom):

- and then (1C)(ii) deprotection of the compound of formula (XLIII) or the salt thereof to prepare the prepare a compound of formula (XLII) or a salt thereof:

or
(1D) to prepare a compound of formula (XLIIa), wherein R¹, R², R³, R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5″ and R^6″ are as defined herein for R⁵and R⁶respectively provided that there is no OH group in R^5″ or R^6″ or [R^5″ and R^6″ taken together] and provided that R⁸is not H, which is one embodiment of a compound of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), or a salt thereof,

- reaction of an amide of formula (XLVa) or a salt thereof, wherein R⁴and n are as defined herein (in particular when R⁴is a hydrogen atom), and wherein R^5″ and R^6″ are as defined herein for R⁵and R⁶respectively provided that there is no OH group in R^5″ or R^6″ or [R^5″ and R^6″ taken together] and provided that R⁸is not H, with a compound of formula (XLIV) or an acid addition salt thereof (e.g. a sulfonate salt thereof e.g. methanesulfonate or benzenesulfonate salt thereof), wherein X¹¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenenesulfonate), triflate (trifluoromethanesulfonate), or a chlorine, bromine or iodine atom (in particular a chlorine atom):

or
(2) to prepare a compound of formula (XXVIII), which is a compound of formula (I) wherein Ar has sub-formula (w), Q³is a bond, and L is (CH₂)_n, wherein R¹, R², R³, R⁴, R⁵, R⁶and n are as defined herein, or a salt thereof,

- reaction (by substitution) of a compound of formula (XXIX) or a salt thereof, wherein R¹, R², R³, R⁴and n are as defined herein and X¹is a suitable leaving group such as mesylate (methanesulfonate), tosylate (p-toluenesulfonate), or a halogen atom (preferably a halogen atom such as a bromine atom), with an amine of formula (IV) or a salt thereof, wherein R⁵and R⁶are as defined herein:

or
(3) to prepare a compound of formula (XXXa), which is one embodiment of a compound of formula (I) wherein Ar has sub-formula (y1a), (y2b), (y3b) or (y3d), wherein R¹, R², R³, R⁴R⁵, R⁶, m¹, and m²are as defined herein (suitably, m¹and m²can both be 4), or a salt thereof,

- reaction by substitution of a compound of formula (XXXIa), or a salt thereof, wherein R¹, R², R³, R⁴, X¹, m¹, and m²are as defined herein, with an amine of formula (IV), or a salt thereof, wherein R⁵and R⁶are as defined herein:

or
(4 to 10) performing the final step in the synthesis of the compound of formula (I) as described in Processes 4, 5, 6, 7, 8, 9, or 10 (as described herein, e.g. as described hereinabove);
or
(F) converting one compound of formula (I) or a salt thereof, or a protected version thereof or a derivative (e.g. ester derivative) thereof, into another compound of formula (I) or a salt thereof (e.g. as described in Process F hereinabove);
and, in the case of any of Process 1A, 1B, 1C, 1D, 2A, 3, or 4 to 10, or (F), optionally converting the compound of formula (I) into a salt thereof such as a pharmaceutically acceptable salt thereof;
or
(G) to prepare a salt of a compound of formula (I), converting a compound of formula (I) into a salt thereof such as a pharmaceutically acceptable salt thereof.
Preferred, suitable or optional features of the steps in any of Processes 1A, 1B, 1C, 1D, 2A, 3, or 4 to 10, or (F), independently of each other, can be as described above for such correspondingly-numbered and/or -lettered Processes, with all necessary changes being made.
The present invention also provides: (G) a process for preparing a pharmaceutically acceptable salt of a compound of formula (I) comprising conversion of the compound of formula (I) or a salt thereof into the desired pharmaceutically acceptable salt thereof. Such processes can for example be as described herein, e.g. as described in the Salts section above. For example, a pharmaceutically acceptable salt can be an acid addition salt, or less commonly (e.g. if a C(O)OH group is present in the compound) a base addition salt. In one embodiment, a pharmaceutically acceptable acid addition salt is optionally prepared by reaction of a compound of formula (I) with a suitable inorganic or organic acid (e.g. as described hereinabove).
The present invention also provides a compound of formula (I) or a salt thereof, prepared by (or obtainable by) a method as defined herein.

Medical Uses

The present invention also provides a compound of formula (I) or a pharmaceutically acceptable salt thereof for use as an active therapeutic substance in a mammal such as a human. The compound or salt can be for use in the treatment and/or prophylaxis of any of the diseases/conditions described herein (e.g. for use in the treatment and/or prophylaxis of an inflammatory and/or allergic disease in a mammal such as a human, monkey, rodent (e.g. rat or mouse) or dog, in particular in a human) and/or can be for use as a phosphodiesterase 4 (PDE4) inhibitor. “Therapy” may include treatment and/or prophylaxis.
Also provided is the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament (e.g. pharmaceutical composition) for the treatment and/or prophylaxis of any of the diseases/conditions described herein in a mammal such as a human, e.g. for the treatment and/or prophylaxis of an inflammatory and/or allergic disease in a mammal such as a human.
Also provided is a method of treatment and/or prophylaxis of any of the diseases/conditions described herein in a mammal (e.g. human) in need thereof, e.g. a method of treatment and/or prophylaxis of an inflammatory and/or allergic disease in a mammal (e.g. human) in need thereof, which method comprises administering to the mammal (e.g. human) a therapeutically effective amount of a compound of formula (I) as herein defined or a pharmaceutically acceptable salt thereof.
Phosphodiesterase 4 inhibitors may be useful in the treatment and/or prophylaxis of a variety of diseases/conditions, especially inflammatory and/or allergic diseases, in a mammal such as a human, for example: chronic obstructive pulmonary disease (COPD) (e.g. chronic bronchitis and/or emphysema), asthma, rhinitis (e.g. allergic and/or non-allergic rhinitis), rheumatoid arthritis, atopic dermatitis, psoriasis, urticaria, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, septic shock, inflammatory bowel disease (e.g. ulcerative colitis and/or Crohn's disease), reperfusion injury of the myocardium and/or brain, chronic glomerulonephritis, endotoxic shock, or adult respiratory distress syndrome, in a mammal such as a human; in particular: chronic obstructive pulmonary disease (COPD) (e.g. chronic bronchitis and/or emphysema), asthma, rhinitis (e.g. allergic and/or non-allergic rhinitis), atopic dermatitis, psoriasis, urticaria, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, inflammatory bowel disease (e.g. ulcerative colitis and/or Crohn's disease), or adult respiratory distress syndrome, in a mammal such as a human.
In the treatment and/or prophylaxis using the compound of formula (I) or the pharmaceutically acceptable salt thereof, the inflammatory and/or allergic disease can for example be chronic obstructive pulmonary disease (COPD), asthma, rhinitis (e.g. allergic and/or non-allergic rhinitis), atopic dermatitis or psoriasis, in a mammal (e.g. human). Preferably, the compound of formula (I) or the pharmaceutically acceptable salt thereof is for the treatment and/or prophylaxis of COPD, asthma or rhinitis (e.g. allergic and/or non-allergic rhinitis), in a mammal (e.g. human).
PDE4 inhibitors, for example cilomilast and roflumilast, are thought to be effective in the treatment of COPD. For example, see S. L. Wolda, Emerging Drugs, 2000, 5(3), 309-319; Z. Huang et al., Current Opinion in Chemical Biology, 2001, 5: 432-438; H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; A. M. Vignola, Respiratory Medicine, 2004, 98, 495-503; D. Spina, Drugs, 2003, 63(23), 2575-2594; and references cited in the aforementioned publications; G. Krishna et al., Expert Opinion on Investigational Drugs, 2004, 13(3), 255-267 (see especially pp. 259-261 and refs. 102-111 and 201 therein); and B. J. Lipworth, The Lancet, 2005, 365, 167-175.
The PDE4 inhibitor cilomilast (Ariflo™) at 15 mg orally twice daily appears to improve forced expiratory volume in 1s (FEV₁) in COPD patients (C. H. Compton et al., The Lancet, 2001, vol. 358, 265-270), and appears to have antiinflammatory effects in COPD patients (E. Gamble et al., Am. J. Respir. Crit. Care Med., 2003, 168, 976-982). On cilomilast, see also R. D. Border et al., Chest, 2003, vol. 124 Suppl. 4, p. 170S (abstract) and J. D. Eddleston et al., Am. J. Respir. Crit. Care Med., 2001, 163, A277 (abstract). The PDE4 inhibitor roflumilast appears to show small improvements in FEV₁in COPD patients (see B. J. Lipworth, The Lancet, 2005, 365, 167-175, and refs 49-50 therein).
COPD is often characterised by the presence of airflow obstruction due to chronic bronchitis and/or emphysema (e.g., see S. L. Wolda, Emerging Drugs, 2000, 5(3), 309-319).
For treatment and/or prophylaxis of COPD or asthma in a mammal (e.g. human), inhaled or parenteral administration to the mammal of the compound of formula (I) or a pharmaceutically acceptable salt thereof can be used, preferably inhaled administration.
PDE4 inhibitors are thought to be effective in the treatment and/or prophylaxis of asthma (e.g. see M. A. Giembycz, Drugs, February 2000, 59(2), 193-212; Z. Huang et al., Current Opinion in Chemical Biology, 2001, 5: 432-438; H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; P. J. Barnes, Nature Reviews—Drug Discovery, October 2004, 831-844; B. J. Lipworth, The Lancet, 2005, 365, 167-175; and references cited in the aforementioned publications).
In one preferred embodiment, the compound of formula (I) or the pharmaceutically acceptable salt thereof is for the treatment and/or prophylaxis of rhinitis, such as allergic rhinitis (e.g. seasonal allergic rhinitis or perennial allergic rhinitis) and/or non-allergic rhinitis (e.g. vasomotor rhinitis or cold air rhinitis), in a mammal such as a human. One embodiment involves the treatment and/or prophylaxis of mixed allergic/non-allergic rhinitis in a mammal such as a human. By way of example, for rhinitis such as allergic and/or non-allergic rhinitis, intranasal or parenteral administration of the compound of formula (I) or a pharmaceutically acceptable salt thereof is optionally used.
The PDE4 inhibitor roflumilast, given orally at 500 ug once daily for 9 days, is reported to be effective in improving rhinal airflow during the treatment period (compared to placebo), in humans with histories of allergic rhinitis but asymptomatic at screening, and who were challenged with intranasal allergen provocation (pollen extracts) daily beginning the third day of treatment and each time approx. 2 hours after study drug administration (B. M. Schmidt et al., J. Allergy & Clinical Immunology, 108(4), 2001, 530-536).
PDE4 inhibitors may be effective in the treatment of rheumatoid arthritis (e.g. see H. J. Dyke et al., Expert Opinion on Investigational Drugs, January 2002, 11(1), 1-13; C. Burnouf et al., Current Pharmaceutical Design, 2002, 8(14), 1255-1296; and A. M. Doherty, Current Opinion Chem. Biol., 1999, 3(4), 466-473; and references cited in these publications). For rheumatoid arthritis, parenteral administration is optionally used.
PDE4 inhibition has been suggested for the treatment of inflammatory bowel disease (e.g. ulcerative colitis and/or Crohn's disease), see K. H. Banner and M. A. Trevethick, Trends Pharmacol. Sci., August 2004, 25(8), 430-436.
In one embodiment, the compound or salt can for example be for use in the treatment and/or prophylaxis of an inflammatory and/or allergic skin disease, such as atopic dermatitis or psoriasis, in a mammal such as a human.
In one optional embodiment, the treatment and/or prophylaxis is of atopic dermatitis in a mammal such as a human or pig, preferably in a human, in particular in a human aged 21 years or less, e.g. 18 years or less. For treatment and/or prophylaxis of atopic dermatitis in a mammal, external topical administration to the mammal of the compound of formula (I) or a pharmaceutically acceptable salt thereof (e.g. topical administration to the skin e,g. to skin affected by the atopic dermatitis) can be used, though alternatively oral or parenteral administration can be used. For treatment and/or prophylaxis of atopic dermatitis, inhaled administration is usually not suitable.
“Atopic dermatitis” has been proposed to include two general sub-classes: (1) an “allergic (extrinsic)” type of atopic dermatitis which generally occurs in the context of sensitization to environmental allergens and/or which is generally accompanied by elevated serum IgE levels; and (2) an “non-allergic (intrinsic)” type of atopic dermatitis generally with little or no detectable sensitization and/or generally with normal or low serum IgE levels (N. Novak et al., J. Allergy Clin. Immunol., 2003, 112,252-262; and T. C. Roos et al., Drugs, 2004, 64(23), 2639-2666, see e.g. pages 2640-2641). The compound of formula (I) or the pharmaceutically acceptable salt thereof can therefore be for the treatment and/or prophylaxis of allergic (extrinsic) atopic dermatitis and/or non-allergic (intrinsic) atopic dermatitis in a mammal (e.g. human or pig, preferably human).
“External topical” administration means topical administration to an external body part (i.e. excluding, for example, the lung or mouth, but including the lips), preferably excluding the eye.
“External topical” administration preferably is topical administration to the skin, for example to the skin of an arm, hand, leg, foot, head (e.g. face), neck and/or torso of a mammal such as a human. External topical administration can for example be to those parts of a mammal's skin affected by or susceptible to atopic dermatitis.
For the use of PDE4 inhibitors in atopic dermatitis, see for example:

For the use of the PDE4 inhibitors SB 207499 (cilomilast) and AWD 12-281 in mouse models of the allergic type of dermatitis, see W. Bäumer et al., Eur. J. Pharmacol., 2002, 446, 195-200 and W. Bäumer et al., J. Pharmacy Pharmacol., 2003, 55, 1107-1114.

Pharmaceutical Compositions, Routes of Administration, and Dosage Regimens

For use in medicine, the compounds or salts of the present invention are usually administered as a pharmaceutical composition.
The present invention therefore provides in a further aspect a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers and/or excipients.
The pharmaceutical composition can be for use in the treatment and/or prophylaxis of any of the conditions described herein, for example chronic obstructive pulmonary disease (COPD), asthma, rhinitis (e.g. allergic rhinitis), atopic dermatitis or psoriasis in a mammal (e.g. human).
The invention also provides a method of preparing a pharmaceutical composition comprising a compound of formula (I), as herein defined, or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable carriers and/or excipients,

- the method comprising mixing the compound or salt with the one or more pharmaceutically acceptable carriers and/or excipients.

The invention also provides a pharmaceutical composition prepared by said method.
The compounds of formula (I) or salts thereof and/or the pharmaceutical composition may be administered, for example, by inhaled, intranasal, external topical (e.g. skin topical), parenteral (e.g. intravenous, subcutaneous, or intramuscular), or oral administration, for example to a mammal such as a human. Inhaled administration involves topical administration to the lung e.g. by aerosol or dry powder composition.
Accordingly, the pharmaceutical composition can be suitable for (e.g. adapted for) inhaled, intranasal, external topical (e.g. skin topical), parenteral (e.g. intravenous, subcutaneous, or intramuscular), or oral administration, e.g. to a mammal such as a human. The pharmaceutical composition can for example be suitable for inhaled, intranasal or external topical (e.g. skin topical) administration, e.g. to a mammal such as a human.
Inhaled or intranasal administration, in particular inhaled administration, is generally a preferred route of administration.
Oral administration is generally not a preferred route of administration.
The pharmaceutical composition can optionally be in unit dose form. The unit dose form can for example be:

- (a) a rupturable or peel-openable sealed dose container containing a dry powder inhalable pharmaceutical composition (e.g. a plurality of which are usually disposed inside a suitable inhalation device);
- (b) a vial, ampoule or filled syringe for parenteral administration e.g. comprising a solution or suspension of the compound or pharmaceutically acceptable salt in a suitable carrier such as an aqueous carrier or e.g. containing a lyophilised parenteral pharmaceutical composition (the vial or ampoule can optionally be manufactured using a blow-fill-seal process); or
- (c) a tablet or capsule for oral administration e.g. for oral administration to a human.

Alternatively, the composition can be in a form adapted for the administration of varying amounts of composition as desired by the user, such as a spreadable or sprayable external topical composition such as a cream, an ointment, a gel, or a liquid.

Pharmaceutical Compositions Suitable for Inhalable or Intranasal Administration, and Particle-Size Reduction

Pharmaceutical compositions suitable for (e.g. adapted for) intranasal or inhaled administration may conveniently be formulated as aerosols, solutions, suspensions, drops, gels or dry powders. Pharmaceutical compositions suitable for (e.g. adapted for) intranasal or inhaled administration may optionally be formulated with one or more pharmaceutically acceptable carriers and/or excipients such as an aqueous or non-aqueous vehicle, a suspending agent, a thickening agent, a wetting agent, an isotonicity adjusting agent, an antioxidant and/or a preservative.
For compositions suitable for intranasal or inhaled administration, the compound of formula (I) or a pharmaceutically acceptable salt thereof may typically be in a particle-size-reduced form, which may be prepared by conventional techniques, for example, micronisation and milling. Generally, the size-reduced (e.g. micronised) compound of formula (I) or a pharmaceutically acceptable salt thereof can be defined by a D₅₀value of about 0.5 to 10 microns, such as of about 2 to 4 microns (for example as measured using laser diffraction).

Pharmaceutical Compositions Suitable for Intranasal Administration

In one embodiment, compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof are suitable for intranasal administration. In the composition for intranasal administration, a liquid vehicle such as an aqueous (liquid) vehicle is typically used. In the composition for intranasal administration, the compound of formula (I) or the salt thereof can be present, for example, as a suspension in a liquid vehicle (e.g. as a suspension in an aqueous (liquid) vehicle) and/or as a solution for example as an aqueous solution.
Intranasal compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof may permit the compound(s) to be delivered to all areas of the nasal cavities (the target tissue) and further, may permit the compound(s) to remain in contact with the target tissue for longer periods of time. One possible dosing regime for intranasal compositions would be for the patient to inhale slowly through the nose subsequent to the nasal cavity being cleared. During inhalation the composition would be administered to one nostril while the other is manually compressed. This procedure would then be repeated for the other nostril. Typically, one or two sprays per nostril would be administered by the above procedure up to two or three times each day, ideally once daily. Intranasal compositions can be for once daily administration.
Intranasal compositions may optionally contain one or more suspending and/or thickening agents, one or more preservatives, one or more wetting and/or solublising agents and/or one or more isotonicity adjusting agents as desired. Compositions suitable for intranasal administration may optionally further contain other excipients, such as antioxidants (for example sodium metabisulphite), taste-masking agents (such as menthol) and/or sweetening agents (for example dextrose, glycerol, saccharin and/or sorbitol).
A suspending and/or thickening agent, if included, will typically be present in the intranasal composition in an amount of from about 0.05 to about 5% w/w or from about 0.1 to about 5% w/w, such as from about 0.05 to about 1% w/w (e.g. about 0.1 to about 0.5% w/w, e.g. about 0.2% w/w, e.g. for xanthan gum) or from about 1% to about 3% w/w, based on the total weight of the composition. A suspending and/or thickening agent can include xanthan gum, microcrystalline cellulose (e.g. Avicel®), carboxymethylcellulose (e.g. carboxymethylcellulose sodium), veegum, tragacanth, bentonite, methylcellulose and polyethylene glycols; in particular xanthan gum, microcrystalline cellulose or carboxy methylcellulose sodium. One particular suspending and/or thickening agent is xanthan gum.
Suspending agents may also be included in compositions suitable for inhaled or oral liquid administration, as appropriate.
For stability purposes, intranasal compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof may be protected from microbial or fungal contamination and growth by inclusion of a preservative. Examples of pharmaceutically acceptable anti-microbial agents or preservatives may include quaternary ammonium compounds (e.g. benzalkonium chloride, benzethonium chloride, cetrimide and cetylpyridinium chloride), mercurial agents (e.g. phenylmercuric nitrate, phenylmercuric acetate and thimerosal), alcoholic agents (e.g. chlorobutanol, phenylethyl alcohol and benzyl alcohol), antibacterial esters (e.g. esters of para-hydroxybenzoic acid), chelating agents such as disodium ethylenediaminetetraacetate (EDTA, also called disodium edetate), and other anti-microbial agents such as chlorhexidine, chlorocresol, sorbic acid and its salts (such as potassium sorbate), polymyxin and sodium benzoate. In particular, the pharmaceutically acceptable anti-fungal agent or preservative can for example include potassium sorbate (e.g. 0.1% to 1% w/w, e.g. about 0.3% w/w) and/or disodium ethylenediaminetetraacetate (EDTA, also called disodium edetate) (e.g. 0.005% to 0.5% w/w, e.g. about 0.015% w/w). The preservative, if included, may be present in an amount of between about 0.001 and 1% (w/w), such as about 0.015% to 0.3% (w/w), based on the total weight of the composition. Preservatives may be included in compositions suitable for other routes of administration as appropriate.
Compositions which contain a suspended medicament may include a pharmaceutically acceptable wetting agent which functions to wet the particles of medicament to facilitate dispersion thereof in a or the aqueous phase of the composition. Typically, the amount of wetting agent used will not cause foaming of the dispersion during mixing. Examples of wetting agents include fatty alcohols, esters and ethers, such as polysorbate e.g. a polyoxyethylene sorbitan monooleate such as polyoxyethylene 20 sorbitan monooleate (polysorbate 80). The wetting agent may be present in intranasal compositions in an amount of between about 0.001 and 0.05% (w/w), for example about 0.025% (w/w), based on the total weight of the composition. Wetting agents may be included in compositions suitable for other routes of administration, e.g. for inhaled administration, as appropriate.
Compositions can alternatively or additionally contain a solublising agent, which generally functions to maintain the compound of formula (I) or salt in solution (e.g. aqueous solution) and/or to reduce the amount of precipitation of said compound or salt from solution (e.g. aqueous solution) and/or to decrease the rate of precipitation of said compound or salt from solution (e.g. aqueous solution). Such a solublising agent can include a polysorbate, for example a polyoxyethylene sorbitan monooleate such as polyoxyethylene 20 sorbitan monooleate (polysorbate 80) or polyoxyethylene 5 sorbitan monooleate (polysorbate 81), or polyoxyethylene 20 sorbitan monolaurate (polysorbate 20), or polyoxyethylene 20 sorbitan monopalmitate (polysorbate 40), or polyoxyethylene 20 sorbitan monostearate (polysorbate 60). [See The Handbook of Pharmaceutical Excipients 4th edition 2003 pp. 479-483 for polysorbates, and for an explanation of polyoxyethylene 20 sorbitan monooleate meaning it is the prepared at least in part by copolymerisation with about 20 moles of ethylene oxide for each mole of sorbitol and/or sorbitol anhydrides used.] The solubilising agent can be present in intranasal compositions in an amount of from about 0.25% to about 10% (w/w) such as about 1% to about 10% (w/w), for example about 1% to about 5% (w/w), based on the total weight of the composition.
An isotonicity adjusting agent may be included to achieve isotonicity with body fluids e.g. fluids of the nasal cavity, resulting in reduced levels of irritancy. The isotonicity adjusting agent can include sodium chloride, dextrose, xylitol or calcium chloride, in particular xylitol or dextrose. An isotonicity adjusting agent may be included in intranasal compositions in an amount of from about 0.1 to about 10% w/w, such as from about 1% to about 10% w/w or from about 2% to about 10% w/w, e.g. about 4 to about 5% (w/w), based on the total weight of the composition. Isotonicity adjusting agents may also be included in compositions suitable for other routes of administration, for example in compositions suitable for inhaled, oral liquid or parenteral administration, as appropriate. One particular isotonicity adjusting agent is xylitol.
Further, the intranasal compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof may be buffered by the addition of suitable buffering agents such as sodium citrate, citric acid, phosphates such as disodium phosphate (for example the dodecahydrate, heptahydrate, dihydrate and anhydrous forms) or sodium phosphate, or mixtures thereof, in particular sodium citrate and/or citric acid. Buffering agents may also be included in compositions suitable for other routes of administration as appropriate.
Compositions for administration topically to the nose or lung for example, for the treatment of rhinitis, include pressurised aerosol compositions (e.g. for inhaled administration/topical to the lung administration) and aqueous compositions for delivery to the nasal cavities by pressurised pump. Compositions which are non-pressurised and adapted to be administered topically to the nasal cavity are of particular interest. Suitable compositions contain water as the diluent or carrier for this purpose. Aqueous compositions for administration to the lung or nose may be provided with excipients such as buffering agents, tonicity modifying agents and the like. Aqueous compositions may also be administered to the nose by nebulisation.
A fluid dispenser may typically be used to deliver a fluid composition to the nasal cavities. The fluid composition may be aqueous or non-aqueous, but typically aqueous. Such a fluid dispenser may have a dispensing nozzle or dispensing orifice through which a metered dose of the fluid composition is dispensed upon the application of a user-applied force to a pump mechanism of the fluid dispenser. Such fluid dispensers are generally provided with a reservoir of multiple metered doses of the fluid composition, the doses being dispensable upon sequential pump actuations. The dispensing nozzle or orifice may be configured for insertion into the nostrils of the user for spray dispensing of the fluid composition into the nasal cavity. A fluid dispenser of the aforementioned type is described and illustrated in WO05/044354. The dispenser has a housing which houses a fluid discharge device having a compression pump mounted on a container for containing a fluid composition. The housing has at least one finger-operable side lever which is movable inwardly with respect to the housing to cam the container upwardly in the housing to cause the pump to compress and pump a metered dose of the composition out of a pump stem through a nasal nozzle of the housing. In one embodiment, the fluid dispenser is of the general type illustrated in FIGS. 30-40 of WO05/044354.

Particle Size Reduction of Compound of Formula (I) or Salt Thereof

In, for example, pharmaceutical compositions suitable for (e.g. adapted for) inhaled administration, the compound or salt of formula (I) can be in a particle-size-reduced form. The size-reduced form can for example be obtained or obtainable by micronisation. Micronisation usually involves subjecting the compound/salt to collisional and/or abrasional forces in a fast-flowing circular or spiral/vortex-shaped airstream often including a cyclone component. The particle size of the size-reduced (e.g. micronised) compound or salt can be defined by a D50 value of about 0.5 to about 10 microns, e.g. about 1 to about 7 microns or about 1 to about 5 microns (e.g. as measured using laser diffraction). For example, the compound or salt of formula (I) can have a particle size defined by: a D10 of about 0.3 to about 3 microns (e.g. about 0.4 to about 2 microns, or about 0.5 to about 1 microns), and/or a D50 of about 0.5 to about 10 microns or about 1 to about 7 microns or (e.g. about 1 to about 5 microns or about 1.5 to about 5 microns or about 1.5 to about 4 microns), and/or a D90 of about 1 to about 30 microns or about 2 to about 20 microns or about 2 to about 15 microns or about 3 to about 15 microns (e.g. about 2 to about 10 microns or about 4 to about 10 microns); for example as measured using laser diffraction.
In particle size measurements, D90, D50 and D10 respectively mean that 90%, 50% and 10% of the material is less than the micron size specified. D50 is the median particle size. DV90, DV50 and DV10 respectively mean that 90%, 50% and 10% by volume of the material is less than the micron size specified. DM90, DM50 and DM10 respectively mean that 90%, 50% and 10% by weight of the material is less than the micron size specified.
Laser diffraction measurement of particle size can use a dry method (wherein a suspension of the compound/salt in an airflow crosses the laser beam) or a wet method [wherein a suspension of the compound/salt in a liquid dispersing medium, such as isooctane or ca. 0.05% lecithin in isooctane or (e.g. if compound is soluble in isooctane) 0.1% Tween 80 in water, crosses the laser beam]. With laser diffraction, particle size is preferably calculated using the Fraunhofer calculation; and/or preferably a Malvern Mastersizer or Sympatec apparatus is used for measurement. For example, particle size measurement and/or analysis by laser diffraction can use any or all of (e.g. all of) the following apparatus and/or conditions: a Malvern Mastersizer 2000 version apparatus, a dispersing medium of isooctane or ca. 0.05% lecithin in isooctane or ca. 0.1% Tween 80 in water, a stirring speed of ca. 1500-2500 rpm, ca. 30 seconds to ca. 3 mins (e.g. ca. 30 seconds) sonification prior to final dispersion and analysis, a 300 RF (Reverse Fourier) lens, and/or the Fraunhofer calculation with Malvern software. In another example, particle size measurement and/or analysis by laser diffraction can use any or all of (e.g. all of) the following apparatus and/or conditions: a Malvern Mastersizer longbed version apparatus, a dispersing medium of ca. 0.1% Tween 80 in water, a stirring speed of ca. 1500 rpm, ca. 3 mins sonification prior to final dispersion and analysis, a 300 RF (Reverse Fourier) lens, and/or the Fraunhofer calculation with Malvern software.
An illustrative non-limiting example of a small-scale micronisation process is now given:

Micronisation Example

Micronisation of a Compound or Salt of One of the Examples

- Purpose: To micronise a compound or salt of one of the Examples (described hereinafter), e.g. in an amount of approximately 300-3000 mg (e.g. about 300-1000 mg) thereof, using a Jetpharma MC1 micronizer.
- The parent (unmicronised) and micronised materials are analyzed for particle size by laser diffraction and crystallinity by PXRD.

Micronisation Example

General Equipment and Material


Equipment/material	Description and specification

Jetpharma MC1	Nitrogen supply: Air tank with pressure resistant
Micronizer	reinforced tubing (e.g. with 275 psi rate tubing)
Analytical balance	can e.g. be Sartorius Analytical
Top loader balance	can e.g. be Mettler PM400 or Sartorius L420P
Digital Caliper	can e.g. be VWR Electronic caliper
Materials to be	a compound or salt of one of the Examples
micronised

The Jetpharma MC1 Micronizer comprises a horizontal disc-shaped milling housing having: a tubular compound inlet (e.g. angled at ca. 30 degrees to the horizontal) for entry of a suspension of unmicronised compound of formula (I) or salt in a gasflow, a separate gas inlet for entry of gases, a gas outlet for exit of gases, and a collection vessel (micronizer container) for collecting micronised material. The milling housing has two chambers: (a) an outer annular chamber in gaseous connection with the gas inlet, the chamber being for receiving pressurised gas (e.g. air or nitrogen), and (b) a disc-shaped inner milling chamber within and coaxial with the outer chamber for micronising the input compound/salt, the two chambers being separated by an annular wall. The annular wall (ring R) has a plurality of narrow-bored holes connecting the inner and outer chambers and circumferentially-spaced-apart around the annular wall. The holes opening into the inner chamber are directed at an angle (directed part-way between radially and tangentially), and in use act as nozzles directing pressurised gas at high velocity from the outer chamber into the inner chamber and in an inwardly-spiral path (vortex) around the inner chamber (cyclone). The compound inlet is in gaseous communication with the inner chamber via a nozzle directed tangentially to the inner chamber, within and near to the annular wall/ring R. Upper and lower broad-diameter exit vents in the central axis of the inner milling chamber connect to (a) (lower exit) the collection vessel which has no air outlet, and (b) (upper exit) the gas outlet. Inside and coaxial with the tubular compound inlet and longitudinally-movable within it is positioned a venturi inlet (V) for entry of gases. The compound inlet also has a bifurcation connecting to an upwardly-directed material inlet port for inputting material.
In use, the narrow head of the venturi inlet (V) is preferably positioned below and slightly forward of the material inlet port, so that when the venturi delivers pressurised gas (e.g. air or nitrogen) the feed material is sucked from the material inlet port into the gas stream through the compound inlet and is accelerated into the inner milling chamber tangentially at a subsonic speed. Inside the milling chamber the material is further accelerated to a supersonic speed by the hole/nozzle system around the ring (R) (annular wall) of the milling chamber. The nozzles are slightly angled so that the acceleration pattern of the material is in the form of an inwardly-directed vortex or cyclone. The material inside the milling chamber circulates rapidly and particle collisions occur during the process, causing larger particles to fracture into smaller ones. “Centrifugal” acceleration in the vortex causes the larger particles to remain at the periphery of the inner chamber while progressively smaller particles move closer to the centre until they exit the milling chamber, generally through the lower exit, at low pressure and low velocity. The particles that exit the milling chamber are heavier than air and generally settle downward through the lower exit into the collection vessel (micronizer container), while the exhaust gas rises (together with a minority of small particles of micronised material) and escapes into the atmosphere at low pressure and low velocity. A filter sock can optionally be placed in the upper gas outlet to catch fine micronised material.

Micronisation Example

General Procedure

The micronizer is assembled. The narrow head of the venturi inlet is positioned below and slightly forward of the material inlet port and is measured with a micro-caliper to make sure that it is inserted correctly. The grind (ring) (R) and venturi (V) pressures are adjusted according to the values specified in the experimental design (refer to experimental section below) by adjusting the valves on the pressure gauges on the micronizer. The setup is checked for leakage by observing if there is any fluctuation in the reading of the pressure gauges.
Note that the venturi (V) pressure is kept at least about 2 bars greater than the grind (ring) (R) pressure to prevent regurgitation of material, e.g. outwardly from the material inlet port.
Balance performance can be checked with calibration weights. Specified amount of the parent material (input material) is fed manually, generally quite slowly, into the input container of the micronizer using a spatula. The input container plus material is weighed. The equipment pressure is monitored during the micronization process.
[Note: As an optional variation of these procedures, input material may be passed through a sieve/screen (e.g. a 600 micron screen) prior to micronisation in order to de-aggregate the input material, if appropriate or desirable.]
Upon completion of the micronising run, the nitrogen supply is shut off and the micronised material is allowed to settle into the micronizer container. The Venturi pressure valve and the grind (ring) pressure valve can be closed. The micronised powder in the micronizer container (collection vessel) and the cyclone (above the recovery vessel) are collected together into a pre-weighed and labelled collection vial. Any fine micronised material which may have collected in any filter sock, which may have been optionally placed in the upper gas outlet of the microniser, can optionally be tapped down into the collection vessel or cyclone. The weight of the micronised material is recorded. The input container is generally re-weighed in order to calculate the amount of input material by difference. The micronizer can be disassembled and residual PDE4 compound on the micronizer inner surface can be rinsed e.g. with 70/30 isopropyl alcohol/water and collected into a flask. The micronizer can then be thoroughly cleaned, e.g. in a Lancer washing machine, and can be dried before subsequent runs are performed.
In one embodiment, one example of suitable micronisation conditions is: Material input amount about 300 mg to about 1000 mg; Venturi Pressure (V) about 4 to about 10 bar (e.g. about 4-6 bar, e.g. about 4-5 bar); Grind (Ring) Pressure (R) about 2 to about 6 bar (e.g. about 2 bar). Material feed rate can optionally be from about 70 to about 200 mg/min.
% yield=[(Material from collection vessel+Material from cyclone+optionally material from gas outlet)/Material input amount]×100.
Inhaled administration involves topical administration to the lung, such as by aerosol or dry powder composition.

Aerosol Inhalable Compositions

An aerosol formulation (aerosol composition), e.g. for inhaled administration, can be either a suspension or a solution.
Aerosol formulations (aerosol compositions), e.g. for inhaled administration, can optionally comprise a solution or fine suspension of the compound of formula (I) or the pharmaceutically acceptable salt thereof (active substance) in a pharmaceutically acceptable aqueous or non-aqueous liquid (e.g. solvent).
An aerosol formulation (aerosol composition), e.g. for inhaled administration, generally can contain a compound of formula (I) or a pharmaceutically acceptable salt thereof and a suitable propellant (e.g. under pressure) such a suitable organic propellant such as a fluorocarbon or hydrofluorocarbon (HFC) or hydrogen-containing chlorofluorocarbon (HCFC) or a mixture thereof. A hydrofluorocarbon (HFC) propellant can comprise a hydrofluoroalkane, such as 1,1,1,2-tetrafluoroethane or 1,1,1,2,3,3,3-heptafluoropropane or a mixture thereof. Other propellants include chlorofluorocarbons (CFCs) such as dichlorodifluoromethane, trichlorofluoromethane or dichlorotetrafluoroethane.
An aerosol composition may optionally contain additional formulation excipient(s) such as a surfactant and/or a cosolvent. The surfactant can include, but is not limited to, oleic acid, lecithin, an oligolactic acid or derivative e.g. as described in WO94/21229 and/or WO98/34596. The cosolvent can for example comprise ethanol.
Aerosol formulations, e.g. for inhaled administration, can be presented e.g. as a dosage form, e.g. in single or multidose quantities in sterile form in a sealed container, which can take the form of a cartridge or refill for use with an atomising device or inhaler. Alternatively the sealed container may be a unitary dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve (metered dose inhaler, or MDI) which is intended for disposal once the contents of the container have been exhausted. The aerosol formulation dosage form can alternatively take the form of a pump-atomiser.

Dry Powder Inhalable Compositions

For pharmaceutical compositions suitable (e.g. adapted for) inhaled administration, the pharmaceutical composition may for example be a dry powder inhalable composition.
Dry powder inhalable compositions may take the form of capsules and cartridges of, for example, gelatine, or blisters of, for example, laminated aluminium foil, for use in an inhaler or insufflator. Dry powder inhalable compositions may be formulated comprising a powder mix of a compound of formula (I) or a pharmaceutically acceptable salt thereof and a suitable powder base such as lactose or starch.
A dry powder inhalable pharmaceutical composition can comprise a powder base such as lactose or starch, the compound of formula (I) or salt thereof (suitably in particle-size-reduced form, e.g. in micronised form), and optionally a ternary agent. The ternary agent can for example comprise L-leucine, mannitol, trehalose, magnesium stearate, calcium stearate and/or cellobiose octaacetate (e.g. alpha-D-isomer of cellobiose octaacetate, e.g. available from Aldrich). The ternary agent can in particular be magnesium stearate, e.g. magnesium stearate present in an amount of from about 0.05% to about 2% w/w or from about 0.1% to about 1% w/w or from about 0.1% to about 0.5% w/w, such as from about 0.1% to about 0.25% w/w or from about 0.25% to about 1% w/w, for example about 0.5% w/w magnesium stearate. For the use of magnesium stearate in dry powder inhalable compositions, see WO 00/28979 A1 (Skyepharma) and the corresponding publications U.S. Pat. No. 6,645,466 B1 and US 2004/0202616 A1; and/or see WO 00/53157 A1. For cellobiose octaacetate and storage stability, see WO 03/088943.
The dry powder inhalable composition can comprise a dry powder blend of lactose and the compound of formula (I) or salt thereof. The lactose can be lactose hydrate e.g. lactose monohydrate and/or can be inhalation-grade and/or fine-grade lactose. The particle size of the lactose can for example be defined by 90% or more (by weight or by volume) of the lactose particles being less than 1000 microns (micrometres) (e.g. 10-1000 microns e.g. 30-1000 microns) in diameter, and/or 50% or more of the lactose particles being less than 500 microns (e.g. 10-500 microns) in diameter. The particle size of the lactose can for example be defined by 90% or more of the lactose particles being less than 300 microns (e.g. 10-300 microns e.g. 50-300 microns) in diameter, and/or 50% or more of the lactose particles being less than 100 microns in diameter. Optionally, the particle size of the lactose can be defined by 90% or more of the lactose particles being less than 100-200 microns in diameter, and/or 50% or more of the lactose particles being less than 40-70 microns in diameter. In particular, the particle size of the lactose can be about 2% to about 30% or about 3% to about 30% (e.g. 2% to 15%, or 7% to 11%, e.g. about 10%) (by weight or by volume) of the particles are less than 50 microns, or are less than 20 microns (“fines”), or are less than 15 microns (“fines”), in diameter. For example, without limitation, one suitable inhalation-grade lactose is lactose (e.g. 10% fines (e.g. E9334), or 6% fines, or 7% fines, or 11% fines), obtainable from Friesland Foods Domo (formerly Borculo Domo Ingredients), Hanzeplein 25, 8017 JD Zwolle, Netherlands.
In the dry powder inhalable composition the compound of formula (I) or salt thereof can for example be present in about 0.1% to about 70% (e.g. about 0.1% to about 50%, about 0.1% to about 30%, or about 0.1% to about 20%, or about 0.1% to about 10%, such as about 0.4% to about 10%, e.g. about 1% to about 10%, e.g. about 1% to about 5%) by weight of the composition.
Illustrative non-limiting examples of dry powder inhalable compositions follow:

Dry Powder Composition Example 1

Dry Powder Lactose Blend Preparation

Using a size-reduced e.g. micronised form of the compound of formula (I) or salt thereof (e.g. as prepared in a Micronisation Example herein), a dry powder blend can, for example, be prepared by mixing the required amount of the compound/salt (e.g. 10 mg, 1% w/w) with inhalation-grade lactose containing 10% fines (e.g. 990 mg, 99% w/w) in a Teflon™ (polytetrafluoroethene) pot in a Mikro-dismembrator ball-mill (but without a ball bearing) at % speed (ca. 2000-2500 rpm) for about 4 hours at each blend concentration. The Mikro-dismembrator (available from B. Braun Biotech International, Schwarzenberger Weg 73-79, D-34212 Melsungen, Germany; www.bbraunbiotech.com) comprises a base with an upwardly-projecting and sidewardly-vibratable arm to which is attached the Teflon™ pot. The vibration of the arm achieves blending.
Other blends can include: 10% w/w compound/salt (50 mg)+90% w/w lactose (450 mg, inhalation-grade lactose containing 10% fines).
Serial dilution of the 1% w/w blend can achieve e.g. 0.1% and 0.3% w/w blends.

Dry Powder Composition Example 2

Dry Powder Lactose Blend Preparations

Using a micronised form of the compound of formula (I) or salt thereof (e.g. as prepared in a Micronisation Example herein), the dry powder blend can, for example, be prepared by mixing (blending), in a high shear blender (such as an Aeromatic-Fielder Turbo Rapid Volume blender), the required amount of the compound/salt with inhalation-grade lactose, e.g. lactose (such as lactose monohydrate) containing from 2% to 15% w/w fines, such as 7% to 11% w/w fines.
Examples of the contents of these dry powder inhalable compositions are those which are in a dosage unit containing 12.5 mg total amount of dry powder inhalable composition, which can have different constituents as follows:

Dry Powder Composition Example 2(A)

(i) 10 micrograms of the micronised compound of formula (I) or salt thereof (0.08% w/w of the formulation), plus
(ii) 12.49 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(B)

(i) 50 micrograms of the micronised compound of formula (I) or salt thereof (0.4% w/w of the formulation), plus
(ii) 12.45 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(C)

(i) 100 micrograms of the micronised compound of formula (I) or salt thereof (0.8% w/w of the formulation), plus
(ii) 12.4 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(D)

(i) 500 micrograms of the micronised compound of formula (I) or salt thereof (4% w/w of the formulation), plus
(ii) 12.0 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(E)

(i) 1000 micrograms of the micronised compound of formula (I) or salt thereof (8% w/w of the formulation), plus
(ii) 11.5 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(F) with Magnesium Stearate Ternary Agent

(i) 50 micrograms of the micronised compound of formula (I) or salt thereof (0.4% w/w of the formulation), plus
(ii) 62.5 micrograms of magnesium stearate (0.5% w/w of the formulation), plus
(iii) 12.3875 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(G) with Magnesium Stearate Ternary Agent

(i) 500 micrograms of the micronised compound of formula (I) or salt thereof (4% w/w of the formulation), plus
(ii) 62.5 micrograms of magnesium stearate (0.5% w/w of the formulation), plus
(iii) 11.9375 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.

Dry Powder Composition Example 2(H) with Magnesium Stearate Ternary Agent

(i) 1000 micrograms of the micronised compound of formula (I) or salt thereof (8% w/w of the formulation), plus
(ii) 62.5 micrograms of magnesium stearate (0.5% w/w of the formulation), plus
(iii) 11.4375 mg of inhalation-grade lactose, containing from 7% to 11% lactose fines.
The above dry powder inhalable compositions (Dry Powder Composition Example 2(A) to 2(H)) can optionally be formed into a dosage unit as follows:
(a) encapsulated in a rupturable or openable capsule, or
(b) contained within sealed, rupturable or peel-openable, dose containers which are mounted longitudinally in a strip or ribbon which can be inside a suitable inhalation device (e.g. the DISKUS™ inhalation device, e.g. which can optionally be substantially as described in GB 2,242,134 A, see below).

Dry Powder Inhalation Devices

Optionally, in particular for dry powder inhalable compositions, a pharmaceutical composition for inhaled administration can be incorporated into a plurality of sealed dose containers (e.g. containing the dry powder composition) mounted longitudinally in a strip or ribbon inside a suitable inhalation device. The container can be rupturable or peel-openable on demand and the dose, e.g. of the dry powder composition, can be administered by inhalation via a device such as the DISKUS™ device, marketed by GlaxoSmithKline. The DISKUS™ inhalation device can e.g. be substantially as described in GB 2,242,134 A. In such device at least one container for the pharmaceutical composition in powder form (the at least one container preferably being a plurality of sealed dose containers mounted longitudinally in a strip or ribbon) is defined between two members peelably secured to one another; the device comprises: means defining an opening station for the said at least one container; means for peeling the members apart at the opening station to open the container; and an outlet, communicating with the opened container, through which a user can inhale the pharmaceutical composition in powder form from the opened container.
See also WO 03/061743 A1 which discloses a medicament dispenser for use with plural elongate form medicament carriers, each having multiple distinct medicament dose portions carried thereby (e.g. as described in the claims thereof e.g. claim 1). See also WO 2007/012871 A1 which discloses a medicament dispenser for use with at least one medicament carrier carrying multiple distinct medicament portions (e.g. as described in the claims thereof e.g. claim 1).

Pharmaceutical Compositions Suitable for External Topical Administration

A pharmaceutical composition of the invention can for example be suitable for (e.g. adapted for) external topical (e.g. skin topical) administration, for example to a mammal such as a human. The pharmaceutical composition suitable for external topical administration can suitably be for the treatment and/or prophylaxis of atopic dermatitis in a mammal such as a human.
“External topical administration” is defined above under the “medical uses” section. External topical administration can for example be to those parts of the skin affected by or susceptible to the disease or condition e.g. atopic dermatitis, in particular in a mammal (e.g. human) suffering from or susceptible to atopic dermatitis.
An external-topical pharmaceutical composition, e.g. skin topical pharmaceutical composition, can for example be an ointment, a cream (usually an oil-in-water or water-in-oil pharmaceutical composition, usually an emulsion), an aqueous gel, or a microemulsion.
In the external-topical pharmaceutical composition, e.g. an ointment or an oil-in-water or water-in-oil composition, the compound of formula (I) or the pharmaceutically acceptable salt thereof can be present in 0.1% to 10%, such as 0.2% to 5%, or 0.5% to 5%, or 1% to 5%, or 0.5% to 3% (e.g. about 1% or about 2%), by weight of the composition (w/w).
In one optional embodiment, the compound of formula (I) or the pharmaceutically acceptable salt thereof can optionally be in a particle-size-reduced form, for example obtained or obtainable by micronisation. This can be, for example, for use in a pharmaceutical composition suitable for (e.g. adapted for) external topical (e.g. skin topical) administration. See the Particle size reduction sub-section herein, within the Inhalable pharmaceutical compositions section, for more details.
Aqueous solubility: A preliminary screen, which can aim to estimate roughly the aqueous solubility of a compound or salt of the invention, can include (as an approximate summary): (i) creating a ca. 10 mM solution of the compound in DMSO, (ii) diluting a portion of this DMSO solution by mixing about 19 parts by volume of pH 7.4 aqueous phosphate buffered saline (PBS) buffer with 1 part by volume of the ca. 10 mM DMSO solution, (iii) “filtering” the mixture with the aid of centrifugation, and then (iv) measuring the concentration of the dissolved compound in the “filtrate”. Although some DMSO (about 5% by volume) is usually present in this solubility screen “filtrate”, the results can be a very approximate estimate of aqueous solubility, e.g. at room temperature.
Lipophilicity: The clogP (calculated log of the octanol/water partition coefficient (P)) of a particular compound or salt of the invention can estimate the lipophilicity of the compound or salt.
Solubilising and/or skin-penetration-enhancing agents: In one embodiment, an external-topical pharmaceutical composition, e.g. an ointment or an oil-in-water cream or water-in-oil cream, suitably includes an agent which acts as a skin-penetration enhancer for and/or a solubiliser of the compound of formula (I) or the salt thereof. The skin-penetration-enhancing- and/or solubilising-agent can for example be propylene glycol, diethylene glycol monoethyl ether (e.g. TRANSCUTOL™) and/or caprylocaproyl macrogolglycerides (e.g. LABRASOL™), such as propylene glycol. The solubiliser and/or skin-penetration enhancer suitably does not comprise DMSO. The solubiliser and/or skin-penetration enhancer can be both a solubiliser and skin-penetration enhancer, and/or can for example be present in 0.5% to 50%, suitably 5% to 50%, more suitably 7% to 30%, for example 7% to 25%, such as about 10% to about 20% (e.g. about 10% or about 20%), by weight of the composition (w/w).
The skin-penetration enhancer is for delivery of the compound of formula (I) or salt thereof (“active agent” or “drug”) through the skin. Solubilization of the drug also helps. The solubilising and/or skin-penetration-enhancing agents should ideally (a) be safe and/or tolerable, (b) have as low a potential for skin irritancy as possible consistent with being an effective skin penetration enhancer, and (c) be compatible with the active pharmaceutical ingredient. Note that the agent can e.g. function both as a solubilising agent and a skin-penetration-enhancing agent.
Suffactants: An external-topical pharmaceutical composition, e.g. an ointment or in particular an oil-in-water cream or water-in-oil cream, can include a surfactant (e.g. as an emulsifier), for example for achieving emulsification of compositions having two or more phases. The total surfactant content can for example be 0.3% to 20%, e.g. 0.5% to 15% or 0.5% to 12% or 0.5% to 10% or 1% to 12% or 3% to 10%, by weight of the composition (w/w). The surfactant can for example comprise a nonionic surfactant such as one or more of the following: a polyoxyl C_12-22alkyl ether (e.g. a polyoxyl C_12-18alkyl ether such as polyoxyl cetyl ether or polyoxyl stearyl ether or polyoxyl lauryl ether) (e.g. present at 0.5% to 10% w/w, e.g. 2.5% to 10% w/w such as about 5% to about 8% w/w), glycerol monostearate (e.g. Arlacel 165™) (e.g. present at 0.5% to 10% w/w, e.g. about 2% w/w), sorbitan monostearate (e.g. Span 60™) (e.g. present at 0.05% to 10% w/w, e.g. about 1% w/w), and cetyl alcohol and/or stearyl alcohol (e.g. cetostearyl alcohol, e.g. wherein the total of any cetyl alcohol and any stearyl alcohol present is 0.5% to 15% w/w, e.g. 1% to 10% w/w such as 2% to 10% w/w or 5% to 10% w/w). Polyoxyl stearyl ether (steareth) can e.g. be a polyoxyl 2-21 stearyl ether, such as polyoxyl 2 stearyl ether (steareth-2), polyoxyl 10 stearyl ether (steareth-10), polyoxyl 20 stearyl ether (steareth-20) or polyoxyl 21 stearyl ether (steareth-21). Polyoxyl cetyl ether (ceteth) can e.g. be a polyoxyl 2-20 cetyl ether such as ceteth-2, ceteth-10 or ceteth-20. Polyoxyl alkyl ethers are also named polyoxyethylene alkyl ethers. Alternatively or additionally, the surfactant can for example comprise an ionic surfactant such as sodium dodecyl sulfate (SDS)=sodium lauryl sulfate (e.g. SDS present at 0.3% to 2% w/w such as 0.5% to 1.5% w/w).
Ointments and creams (and oil phase): An external-topical pharmaceutical composition can be an ointment or an oil-in-water cream or water-in-oil cream. The ointment or cream typically contains an oil phase (oily ointment base). The oil phase (ointment base) typically comprises an oil and/or a fat, suitably of a consistency suitable for skin-spreadability.
In particular, an oil comprising or being white soft paraffin (white petrolatum) and/or a mineral oil (such as liquid paraffin) can be used. (Mineral oil can also be used as a solubiliser and/or emollient). The white soft paraffin (white petrolatum) can be of various grades, for example (for Penreco supplier) Penreco Regent White grade, Penreco Snow White grade, or Penreco Ultima White grade, in particular high melting point white soft paraffin (e.g. of Penreco Ultima White grade). Microcrystalline wax or beeswax or beeswax substitute can be used as an oil/fat in the oil phase.
Alternatively or additionally, one or more fats like straight or branched chain mono- or di-alkyl esters such as isopropyl myristate, isopropyl palmitate, diisopropyl adipate, isocetyl stearate, isostearyl isostearate, decyl oleate, butyl stearate, 2-ethylhexyl palmitate, propylene glycol diester of coconut fatty acids, or a mixed ester of 2-ethyl hexanoic acid with a blend of cetyl or stearyl alcohols (e.g. known as Crodamol CAP), may be used in the oil phase (some of these are also solubilisers and/or surfactants). These may be used singly or in combination depending on the properties required.
The oil phase (oily ointment base) can for example be present at:

- 30% to 99.8% w/w (e.g. 50% to 99.5% w/w, e.g. 50% to 95% w/w, e.g. 60% to 95% w/w, e.g. 60% to 90% w/w) in an ointment (e.g. emulsion or homogeneous single phase);
- 25% to 85% w/w (e.g. 35% to 70% w/w) in a water-in-oil cream (e.g. emulsion); or
- 5% to 60% w/w or 8% to 55% w/w (e.g. 10% to 45% w/w or 12% to 30% w/w) in an oil-in-water cream (e.g. emulsion).

Note that the w/w percentages for the oil phase (oily ointment base), mentioned above or in the example formulations below or generally herein, exclude the amount of any surfactant(s) present (except for compound(s) listed herein as fats which also have surfactant properties), and exclude the amount of any non-oil non-fat solubilising and/or skin-penetration-enhancing agents present.
Example ointments: As an example, an external-topical pharmaceutical composition can be an ointment comprising:

- the compound of formula (I) or pharmaceutically acceptable salt thereof present at 0.1% to 10% w/w (e.g. 0.2% to 5% w/w, or 0.5% to 5% w/w, or 0.5% to 3% w/w); and
- an oil phase (oily ointment base) present at 30% to 99.8% w/w or 50% to 99.5% w/w or 50% to 95% w/w or 60% to 95% w/w or 60% to 90% w/w (i.e. by weight of the composition).

For example, in the above example ointment, the oil phase or composition can suitably comprise white petrolatum present at 25% to 99.5% w/w or 45% to 99% w/w or 55% to 85% w/w (i.e. by weight of the composition). Optionally, additionally or alternatively, the oil phase or composition can comprise mineral oil (e.g. as solubiliser and emollient) present at 2.5% to 25% w/w such as 4% to 20% w/w (i.e. by weight of the composition)].
In the above example ointment, the ointment can optionally comprise one or more surfactants (e.g. polyoxyl stearyl ether, polyoxyl cetyl ether or cetostearyl alcohol) present in total at 0.5% to 10% w/w or 3% to 10% w/w.
In the above example ointment, the ointment can optionally comprise one or more agents acting as a skin-penetration enhancer (in particular acting as both a solubiliser and skin-penetration enhancer and/or in particular hydrophilic such as propylene glycol) present in total at 0.5% to 50% w/w, such as 5% to 50% w/w or 7% to 30% w/w.
In the above example ointment, the ointment can optionally comprise (a) one or more antioxidants (e.g. butylated hydroxyanisole), e.g. present in total at 0.001% to 2% w/w such as 0.02% to 2% w/w; and/or (b) one or more preservatives, e.g. present in total at 0.01% to 4% w/w such as 0.05% to 1% w/w (e.g. methylparaben present at 0.05% to 2% w/w and/or propylparaben present at 0.01% to 2% w/w).
The above example ointment composition, including the oil “phase” and an optional penetration enhancer, can optionally be a homogeneous single phase. However, in one embodiment of the above example ointment composition, e.g. when using propylene glycol or another hydrophilic solubiliser and penetration enhancer, the oil phase (oily ointment base) and a hydrophilic phase containing the hydrophilic solubiliser and penetration enhancer (e.g. propylene-glycol-containing phase) have been emulsified to form an ointment emulsion.
Ointment compositions having two phases can optionally be prepared using an emulsification process whereby the hydrophilic phase (e.g. propylene-glycol-containing phase) and oil phase are first prepared in separate vessels. The hydrophilic phase can optionally contain a penetration enhancer such as propylene glycol, and optionally some or all of the compound of formula (I) or salt thereof. The oil phase can optionally contain a surfactant. Temperatures of both phases are maintained at elevated temperatures, such as about 55-90° C. or in particular from above 70 to 90° C., the oil phase temperature being sufficiently high (e.g. from above 70 to 90° C.) to melt the oil phase. While hot, one phase is added to another while mixing, e.g. using a high shear mixer, to effect emulsification, e.g. keeping the temperature above 70° C. such as from above 70 to 90° C. The resulting ointment emulsion is allowed to cool, e.g. to about 15-35° C. such as to about 18-30° C., in particular while the agitation continues e.g. at lower speeds. The ointment emulsion can then optionally be dispensed from the manufacturing vessel and filled into primary packaging, for example tubes or sachets.
Optionally, an ointment can comprise a polyethylene glycol base, e.g. present at 25% to 99% w/w such as 50% to 98% w/w, instead of or as well as an oily ointment base.
Creams: An external-topical pharmaceutical composition can be a cream, e.g. a water-in-oil cream or an oil-in-water cream. Creams can sometimes be more fluid than ointments, can sometimes provide more moisture, and hence may in principle in certain cases allow for improved and/or good efficacy in patients with atopic dermatitis.
Water-in-oil creams: These usually have an increased aqueous content compared to ointments. In particular the water-in-oil cream can be a water-in-oil cream emulsion. That is, in particular, in the water-in-oil cream, an oil phase and an aqueous phase can have been emulsified to form a water-in-oil cream emulsion.
As an example, an external-topical pharmaceutical composition can be a water-in-oil cream (e.g. cream emulsion) comprising:

- the compound of formula (I) or pharmaceutically acceptable salt thereof present at 0.1% to 10% w/w (e.g. 0.2% to 5% w/w, or 0.5% to 5% w/w, or 0.5% to 3% w/w);
- an oil phase (oily ointment base) present at 25% to 85% w/w or 35% to 70% w/w [for example: comprising white petrolatum present at 25% to 75% w/w or 30% to 65% w/w (i.e. by weight of the composition), and/or comprising mineral oil (e.g. as solubiliser and emollient) present at 2.5% to 20% w/w or 4% to 15% w/w (i.e. by weight of the composition)];
- water present in 2% to 30% w/w, e.g. 5% to 25% or 10% to 22% w/w;
- one or more surfactants (e.g. polyoxyl stearyl ether) present in total at 0.5% to 12% w/w, such as 3% to 10% w/w; and
- in particular, one or more agents acting as a skin-penetration enhancer (e.g. acting as both a solubiliser and skin-penetration enhancer and/or e.g. hydrophilic such as propylene glycol) present in total at 0.5% to 50% w/w, such as 5% to 50% w/w or 7% to 30% w/w; and
- optionally, one or more antioxidants (e.g. butylated hydroxyanisole), e.g. present in total at 0.001 to 2% w/w such as 0.02 to 2% w/w; and
- optionally, one or more preservatives, e.g. present in total at 0.01 to 4% w/w such as 0.05 to 1% w/w (e.g. methylparaben present at 0.05 to 2% w/w and/or propylparaben present at 0.01 to 2% w/w).

Oil-in-water creams: These usually have an increased aqueous content compared to ointments and water-in-oil creams. In particular, the oil-in-water cream can be an oil-in-water cream emulsion. That is, preferably, in the oil-in-water cream, an oil phase and an aqueous phase have been emulsified to form an oil-in-water cream emulsion.
Examples of oil-in-water creams are high-occlusion creams, wherein, after topical administration to the skin, moisture loss from the skin and/or from the cream is reduced or limited by means of sufficiently high coverage of the skin and/or by providing a sufficient barrier at the site of application.
In particular, the oil-in-water cream can contain one or more emollients (hydrating agents), such as silicones (e.g. dimethicone, e.g. dimethicone 360 or dimethicone 20), a high-viscosity wax such as microcrystalline wax, and/or mineral oil. A sufficiently high water content is also preferred, for example wherein the water is present in 15% to 60% w/w, 20% to 50% w/w, or 25% to 40% w/w.
As an example, an external-topical pharmaceutical composition can be an oil-in-water cream (e.g. cream emulsion) comprising:

- the compound of formula (I) or pharmaceutically acceptable salt thereof present at 0.1% to 10% w/w (e.g. 0.2% to 5% w/w, or 0.5% to 5% w/w, or 0.5% to 3% w/w);
- an oil phase (oily ointment base), in particular containing one or more ingredients capable of acting as emollients, the oil phase being present at 5% to 60% w/w or 8% to 55% w/w or in particular 10% to 45% w/w or 12% to 30% w/w;
- water present in 7% to 75% w/w or 7% to 60% w/w or 10% to 60% w/w, in particular 15% to 50% w/w or 20% to 40% w/w;
- one or more surfactants present in total at 0.5% to 20% w/w, e.g. 3% to 15% w/w or 3% to 10% w/w; and
- preferably, one or more agents acting as a skin-penetration enhancer (e.g. acting as both a solubiliser and skin-penetration enhancer and/or e.g. hydrophilic such as propylene glycol) present in total at 0.5% to 50% w/w, preferably 5% to 50% w/w or 7% to 25% w/w; and
- optionally, one or more solubilisers (e.g. isopropyl myristate), e.g. present at 0.5% to 20% w/w, e.g. 3 to 12% w/w; and
- optionally, one or more buffers (e.g. citric acid and/or dibasic sodium phosphate), e.g. present in total at 0.05 to 5% w/w.

In the above example oil-in-water cream composition, the oil phase in particular can comprise mineral oil (e.g. as emollient and solubiliser) present at 15% to 50% w/w or 20% to 45% w/w (i.e. by weight of the composition), and/or comprises a high-viscosity wax such as microcrystalline wax (e.g. as emollient) present at 5% to 25% w/w such as 8% to 15% w/w, and/or comprises a silicone (such as dimethicone e.g. dimethicone 360 or dimethicone 20, e.g. as emollient) present at 0.5% to 20% such as 0.5% to 10% or 1% to 5% w/w.
In the above example oil-in-water cream composition, the one or more surfactants can in particular comprise: glycerol monostearate present at 0.5% to 10% w/w, and/or sorbitan monostearate present at 0.05% to 10% w/w, and/or [cetyl alcohol and/or stearyl alcohol] present in total at 0.1% to 15% or 1 to 10% w/w.
Cream emulsions, e.g. water-in-oil or oil-in-water cream emulsions, can be prepared by a process in which an aqueous phase is prepared, e.g. prepared before emulsification. The aqueous phase usually contains water and a solubiliser and/or skin-penetration enhancer such as propylene glycol, and optionally contains some or all of the compound of formula (I) or salt thereof, and/or optionally contains surfactant. The oil phase, e.g. containing white petrolatum and/or mineral oil, and/or optionally containing surfactant, can be prepared in a separate vessel. Temperatures of both phases are maintained at elevated temperatures, such as about 55-90° C. or in particular from above 70 to 90° C., the oil phase temperature being sufficiently high (e.g. from above 70 to 90° C.) to melt the oil phase. While hot, one phase is added to another while mixing, e.g. using a high shear mixer, to effect emulsification, in particular keeping the temperature above 70° C. such as from above 70 to 90° C. The resulting emulsion is allowed to cool, e.g. to about 15-35° C. such as to about 18-30° C., in particular while the agitation continues e.g. at lower speeds. The cream emulsion can then optionally be dispensed from the manufacturing vessel and filled into primary packaging, for example tubes or sachets.
Typically, a pharmaceutical composition of the invention suitable for external topical administration can be administered once daily, twice daily or more than twice daily, to external body part(s), e.g. on the skin such as at a site of diseased skin, e.g. skin suffering from atopic dermatitis.

Pharmaceutical Compositions Suitable for Parenteral or Oral Administration

A pharmaceutical composition suitable for (e.g. adapted for) parenteral (e.g. intravenous, subcutaneous, or intramuscular) administration can comprise a solution or suspension of the compound or pharmaceutically acceptable salt in a sterile pharmaceutically and parenterally acceptable aqueous liquid carrier (e.g. sterile water or a sterile aqueous solution) or in a parenterally acceptable oil. Alternatively, an aqueous solution can be lyophilised to prepare the parenteral composition. A lyophilised pharmaceutical composition suitable for (e.g. adapted for) parenteral administration may, in use, optionally be reconstituted with a suitable solvent, e.g. sterile water or a sterile parenterally acceptable aqueous solution, just prior to administration. A pharmaceutical composition suitable for (e.g. adapted for) parenteral administration may optionally comprise a preservative.
As mentioned above, oral administration is generally not thought to be a preferred route of administration. However, in the event that oral administration is to be used, a pharmaceutical composition suitable for oral administration can be liquid or solid; for example it can be a syrup, suspension or emulsion, a tablet, a capsule or a lozenge.
A liquid formulation (e.g. oral) can generally consist of a suspension or solution of the compound or pharmaceutically acceptable salt in a suitable pharmaceutically acceptable liquid carrier(s), for example an aqueous solvent such as water, aqueous ethanol or aqueous glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring and/or colouring agent.
In one embodiment, the pharmaceutical composition is in unit dose form, such as a tablet or capsule for oral administration, e.g. for oral administration to a human.
A pharmaceutical composition suitable for oral administration being a tablet can comprise one or more pharmaceutically acceptable carriers and/or excipients suitable for preparing tablet formulations. The carrier can for example be or include lactose, cellulose (for example microcrystalline cellulose), or mannitol. The tablet can also or instead contain one or more pharmaceutically acceptable excipients, for example a binding agent such as hydroxypropylmethylcellulose or povidone (polyvinylpyrrolidone), a lubricant e.g. an alkaline earth metal stearate such as magnesium stearate, and/or a tablet disintegrant such as sodium starch glycollate, croscarmellose sodium, or crospovidone (cross-linked polyvinylpyrrolidone). The pharmaceutical composition being a tablet can be prepared by a method comprising the steps of: (i) mixing the compound of formula (I), as herein defined, or a pharmaceutically acceptable salt thereof, with the one or more pharmaceutically acceptable carriers and/or excipients, (ii) compressing the resulting mixture (which is usually in powder form) into tablets, and (iii) optionally coating the tablet with a tablet film-coating material.
A pharmaceutical composition suitable for oral administration being a capsule can be prepared using encapsulation procedures. For example, pellets or powder containing the active ingredient can be prepared using a suitable pharmaceutically acceptable carrier and then filled into a hard gelatin capsule. Alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutically acceptable carrier, for example an aqueous gum or an oil and the dispersion or suspension then filled into a soft gelatin capsule.

Dosage Regimens

The pharmaceutical composition can optionally be in unit dose form. The unit dose form can for example be:

In the pharmaceutical composition of the invention, a or each dosage unit for inhaled or intranasal administration can for example contain from 0.005 to 10 mg, such as 0.005 to 7.5 mg (e.g. 0.01 mg, 0.05 mg, 0.1 mg, 0.5 mg or 1 mg), for example 0.02 to 2 mg (e.g. 0.05 mg, 0.1 mg, 0.25 mg, 0.4 mg, 0.5 mg, 0.875 mg or 1 mg) or 0.05 to 2 mg (e.g. 0.05 mg, 0.1 mg, 0.25 mg, 0.4 mg, 0.5 mg, 0.875 mg or 1 mg), of a compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base. A or each dosage unit for oral or parenteral administration can for example contain from 0.02 to 1000 mg, such as 0.2 to 350 mg, of a compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base.
When an inhalable or intranasal composition is used, a pharmaceutically acceptable compound or salt of the invention can for example be administered to a mammal (e.g. human) in a daily inhaled or intranasal dose of: 0.0003 to 0.6 mg/kg body weight/day or 0.0007 to 0.6 mg/kg body weight/day or 0.0007 to 0.1 mg/kg body weight/day, e.g. 0.0007 to 0.015 mg/kg/day or 0.004 to 0.1 mg/kg/day, of the compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base.
A compound, e.g. of formula (I), or a pharmaceutically acceptable salt thereof of the invention can, for example, be administered to a human in a total daily inhaled or intranasal dose of: 0.005 to 10 mg per day, or 0.02 to 7.5 mg per day, or 0.05 to 7.5 mg per day, or 0.05 to 4 mg per day (e.g. 1 mg per day), or 0.25 to 2 mg per day, of the compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base. These total daily doses can be administered as a single dose once daily, or can represent the summation of two or more separate doses administered at different times of the day (e.g. two doses per day administered every ca. 12 hours). These total daily doses can e.g. be for administration to an adult human e.g. of 50-120 kg or 60-100 kg body weight.
For example, a human inhaled or intranasal dosage regimen of 0.05 to 2 mg (e.g. 0.05 mg, 0.1 mg, 0.4 mg, 0.5 mg, 0.875 mg or 1 mg) of the compound or the salt thereof once or twice per day, or 0.2 to 2 mg (e.g. 0.4 mg, 0.5 mg, 0.875 mg or 1 mg) once or twice per day, calculated as the free base, can optionally be administered to a human, for example in the treatment and/or prophylaxis of COPD, asthma or rhinitis (e.g. allergic and/or non-allergic rhinitis) in the human.
When a parenteral or oral composition is used, a pharmaceutically acceptable compound or salt of the invention is optionally, for example, administered to a mammal (e.g. human) in a daily parenteral or oral dose of 0.0003 mg to 15 mg per kg body weight per day (mg/kg/day), for example 0.003 to 5 mg/kg/day, of the compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base.
A compound, e.g. of formula (I), or pharmaceutically acceptable salt thereof of the invention is optionally, for example, administered to a human (e.g. adult human) in a total daily parenteral or oral dose of 0.02 mg to 1000 mg per day or 0.2 to 350 mg per day of the compound (e.g. of formula (I)) or a pharmaceutically acceptable salt thereof, calculated as the free base.
In a pharmaceutical composition suitable for (e.g. adapted for) external topical administration, e.g. an ointment or an oil-in-water or water-in-oil composition, the compound of formula (I) or the pharmaceutically acceptable salt thereof can be present in 0.1% to 10%, such as 0.2% to 5%, or 0.5% to 5%, or 0.5% to 3%, by weight of the composition (w/w). Typically, an external-topical pharmaceutical composition can be administered once daily, twice daily or more than twice daily, to external body part(s), e.g. to the skin such as at a site of diseased skin. The amount administered is usually such as substantially to cover the site(s) of diseased skin.

Combinations

The compounds, salts and/or pharmaceutical compositions according to the invention may also be used in combination with another therapeutically active agent, for example, a β₂adrenoreceptor agonist, an anticholinergic compound (e.g. muscarinic (M) receptor antagonist), an anti-histamine, an anti-allergic, an anti-inflammatory agent, an antiinfective agent or an immunosuppressant.
The invention thus provides, in a further aspect, a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with another therapeutically active agent, for example, a muscarinic (M) receptor antagonist, a β₂-adrenoreceptor agonist (beta-2 adrenoreceptor agonist), an anti-histamine, an anti-allergic, an anti-inflammatory agent, an antiinfective agent or an immunosuppressant.
The invention also provides, in a further preferred aspect, a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with a muscarinic (M) receptor antagonist.
The muscarinic (M) receptor antagonist can be an M₁, M₂, M₁/M₂, or M₃receptor antagonist, such as a M₃receptor antagonist, in particular a M₃receptor antagonist which selectively antagonises (e.g. antagonises 10 times or more strongly) the M₃receptor over the M₁and/or M₂receptor.
For combinations of a muscarinic (M) receptor antagonist with PDE4 inhibitors, see for example WO 03/011274 A2 and WO 02/069945 A2/US 2002/0193393 A1 and US 2002/052312 A1, and some or all of these publications give examples of anticholinergic compounds/muscarinic (M) receptor antagonists which may be used with the compounds of formula (I) or salts, and/or suitable pharmaceutical compositions. For example, the muscarinic receptor antagonist can comprise or be an ipratropium salt (e.g. ipratropium bromide), an oxitropium salt (e.g. oxitropium bromide), or more preferably a tiotropium salt (e.g. tiotropium bromide); see e.g. EP 418 716 A1 for tiotropium.
Muscarinic antagonists which can be optionally used in the combination of the present invention include a compound (including a pharmaceutically acceptable salt thereof) defined by claim 1, 2, 3 or 4 of WO 2005/037280 A1. These compounds are stated or implied as being muscarinic (e.g. M₃) acetylcholine receptor antagonists.
Muscarinic antagonists which can be optionally used in the combination of the present invention include those disclosed in WO 2005/037280, WO 2005/046586 and WO 2005/104745. The muscarinic antagonist can be:

(3-endo)-3-(2,2-di-2-thienylethenyl)-8,8-dimethyl-8-azoniabicyclo[3.2.1]octane iodide;
(3-endo)-3-(2-cyano-2,2-diphenylethyl)-8,8-dimethyl-8-azoniabicyclo[3.2.1]octane bromide;
4-[hydroxy(diphenyl)methyl]-1-{2-[(phenylmethyl)oxy]ethyl}1-azoniabicyclo[2.2.2]octane bromide; or
(1R,5S)-3-(2-cyano-2,2-diphenylethyl)-8-methyl-8-{2-[(phenylmethyl)oxy]ethyl}-8-azoniabicyclo[3.2.1]octane bromide; or a salt of any of the foregoing.

The muscarinic (M) receptor antagonist, e.g. M₃receptor antagonist, is preferably for inhaled administration, more preferably in particle-size-reduced form e.g. as defined herein. More preferably, both the muscarinic (M) receptor antagonist and the compound of formula (I) or the pharmaceutically acceptable salt thereof are for inhaled administration. Suitably, the muscarinic receptor antagonist and the compound of formula (I) or salt are for simultaneous administration. The muscarinic receptor antagonist combination is preferably for treatment and/or prophylaxis of COPD.
In one embodiment, the combination includes a β₂-adrenoreceptor agonist (beta-2 adrenoreceptor agonist) being salmeterol (e.g. as racemate or a single enantiomer such as the R-enantiomer), salbutamol, formoterol, salmefamol, fenoterol, carmoterol, indacaterol or terbutaline, or a salt thereof (e.g. pharmaceutically acceptable salt thereof), for example the xinafoate salt of salmeterol, the sulphate salt or free base of salbutamol or the fumarate salt of formoterol. Long-acting β₂-adrenoreceptor agonists are preferred, especially those having a therapeutic effect over a 12-24 hour period such as salmeterol or formoterol. Preferably, the β₂-adrenoreceptor agonist is for inhaled administration, e.g. once per day and/or for simultaneous inhaled administration; and more preferably the β₂-adrenoreceptor agonist is in particle-size-reduced form e.g. as defined herein. Preferably, the β₂-adrenoreceptor agonist combination is for treatment and/or prophylaxis of COPD or asthma. Salmeterol or a pharmaceutically acceptable salt thereof, e.g. salmeterol xinofoate, can be administered to humans at an inhaled dose of 25 to 50 micrograms twice per day (measured as the free base).
Examples of β₂-adrenoreceptor agonists e.g. long acting β₂-adrenoreceptor agonists for use in the combination include those described in WO 02/066422A, WO 03/024439, WO 02/070490, WO 02/076933, WO 03/072539, WO 03/091204, WO 2004/016578, WO2004/022547, WO 2004/037807, WO 2004/037773, WO 2004/037768, WO 2004/039762, and WO 2004/039766.
In particular, long-acting β₂-adrenoreceptor agonists (beta-2 adrenoreceptor agonists) can include compounds of formula (XX) (described in WO 02/066422):
or a salt or solvate thereof, wherein in formula (XX):
m^Xis an integer of from 2 to 8;
n^Xis an integer of from 3 to 11,
with the proviso that m^X+n^Xis 5 to 19,
R^11Xis —XSO₂NR^16XR^17Xwherein X is —(CH₂)_p ^x— or C_2-6alkenylene;
R^16Xand R^17Xare independently selected from hydrogen, C_1-6alkyl, C_3-7cycloalkyl, C(O)NR^18XR^19x, phenyl, and phenyl (C_1-4alkyl)-,
or R^16Xand R^17X, together with the nitrogen to which they are bonded, form a 5-, 6-, or 7-membered nitrogen containing ring, and R^16Xand R^17Xare each optionally substituted by one or two groups selected from halo, C_1-6alkyl, C_1-6haloalkyl, C_1-6alkoxy, hydroxy-substituted C_1-6alkoxy, —CO₂R^18X, —SO₂NR^18XR^19X, —CONR^18XR^19X, —NR^18XC(O)R^19X, or a 5-, 6- or 7-membered heterocylic ring;
R^18Xand R^19Xare independently selected from hydrogen, C_1-6alkyl,
C_3-6cycloalkyl, phenyl, and phenyl (C_1-4alkyl)-; and
p^Xis an integer of from 0 to 6, preferably from 0 to 4;
R^12xand R^13xare independently selected from hydrogen, C_1-6alkyl, C_1-6alkoxy, halo, phenyl, and C_1-6haloalkyl; and
R^14Xand R^15Xare independently selected from hydrogen and C_1-4alkyl with the proviso that the total number of carbon atoms in R^14Xand R^15Xis not more than 4.
Suitable β₂-adrenoreceptor agonists disclosed in WO 02/066422 include:

3-(4-{[6-({(2R)-2-hydroxy-2-[4-hydroxy-3-(hydroxymethyl)-phenyl]ethyl}amino)hexyl]oxy}butyl)benzenesulfonamide, or
3-(3-{[7-({(2R)-2-hydroxy-2-[4-hydroxy-3-hydroxymethyl)phenyl]ethyl}amino)heptyl]oxy}propyl)benzenesulfonamide; or a salt thereof.

A preferred β₂-adrenoreceptor agonist disclosed in WO 03/024439 is:

4-{(1R)-2-[(6-{2-[(2,6-dichlorobenzyl)oxy]ethoxy}hexyl)amino]-1-hydroxyethyl}2-(hydroxymethyl)phenol or a salt thereof. Suitably, this can be for inhaled administration.

Another example of β₂-adrenoreceptor agonist disclosed in WO 2004/037773 is:

4-{(1R)-2-[(6-{4-[3-(cyclopentylsulfonyl)phenyl]butoxy}hexyl)amino]-1-hydroxyethyl}-2-(hydroxymethyl)phenol or a salt thereof.

An anti-histamine usable in a combination of a compound of formula (I) or salt can for example be for oral administration (e.g. this can be as a separately-administrable tablet), and can be for treatment and/or prophylaxis of allergic rhinitis. Examples of anti-histamines for oral administration include methapyrilene, or H1 antagonists such as cetirizine, loratadine (e.g. Clarityn™), desloratadine (e.g. Clarinex™) or fexofenadine (e.g. Allegra™).
An anti-histamine usable in a combination of a compound of formula (I) or salt can for example be for intranasal administration. An anti-histamine for intranasal administration can e.g. be azelastine or a salt thereof (e.g. azelastine hydrochloride, e.g. 0.1% w/v aqueous solution), or levocabastine or a salt thereof (e.g. levocabastine hydrochloride). The anti-histamine olopatadine (e.g. as olopatadine HCl) can be used e.g. as eye drops.
Other possible combinations include, for example, a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with another anti-inflammatory agent such as an anti-inflammatory corticosteroid; or a non-steroidal anti-inflammatory drug (NSAID) such as a leukotriene antagonist (e.g. montelukast), an iNOS inhibitor, a tryptase inhibitor, a elastase inhibitor, a beta-2 integrin antagonist, a adenosine 2a agonist, or a 5-lipoxogenase inhibitor; or an antiinfective agent (e.g. an antibiotic or an antiviral). An iNOS inhibitor is optionally for oral administration. Examples of iNOS inhibitors (inducible nitric oxide synthase inhibitors) include those disclosed in WO 93/13055, WO 98/30537, WO 02/50021, WO 95/34534 and WO 99/62875.
In a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with an anti-inflammatory corticosteroid (which can for example be for treatment and/or prophylaxis of asthma, COPD, rhinitis e.g. allergic rhinitis, psoriasis or atopic dermatitis), then the anti-inflammatory corticosteroid can be fluticasone propionate (e.g. see U.S. Pat. No. 4,335,121), beclomethasone 17-propionate ester, beclomethasone 17,21-dipropionate ester, dexamethasone or an ester thereof, mometasone or an ester thereof (e.g. mometasone furoate), betamethasone valerate (for external topical administration), clobetasol propionate (for external topical administration), ciclesonide, budesonide, flunisolide, or a compound as described in WO 02/12266 A1 (e.g. as claimed in any of claims 1 to 22 therein), or a pharmaceutically acceptable salt of any of the above. If the anti-inflammatory corticosteroid is a compound as described in WO 02/12266 A1, then it can be Example 1 therein {which is 6α,9α-difluoro-17α-[(2-furanylcarbonyl)oxy]-11β-hydroxy-16α-methyl-3-oxo-androsta-1,4-diene-17β-carbothioic acid S-fluoromethyl ester} or Example 41 therein {which is 6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-[(4-methyl-1,3-thiazole-5-carbonyl)oxy]-3-oxo-androsta-1,4-diene-17β-carbothioic acid S-fluoromethyl ester}, or a pharmaceutically acceptable salt thereof. The anti-inflammatory corticosteroid can for example be for inhaled, intranasal or external topical administration. Fluticasone propionate can be used and is preferably for inhaled administration to a human either (a) at a dose of 250 micrograms once per day or (b) at a dose of 50 to 250 micrograms twice per day. In a combination comprising betamethasone valerate for external topical administration, the betamethasone valerate can be present at from about 0.025% to about 0.1% w/w in an externally-topicallly-administrable composition such as a cream or ointment. In a combination comprising clobetasol propionate for external topical administration, the clobetasol propionate can be present at about 0.0525% w/w or about 0.05% w/w in an externally-topically-administrable composition such as a cream or ointment.
Also provided is a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with β₂-adrenoreceptor agonist and an anti-inflammatory corticosteroid, for example as described in WO 03/030939 A1. Preferably this combination is for treatment and/or prophylaxis of asthma, COPD or allergic rhinitis. The β₂-adrenoreceptor agonist and/or the anti-inflammatory corticosteroid can be as described above and/or as described in WO 03/030939 A1. In this “triple” combination, the β₂-adrenoreceptor agonist can for example be salmeterol or a pharmaceutically acceptable salt thereof (e.g. salmeterol xinafoate), and the anti-inflammatory corticosteroid can for example be fluticasone propionate.
Other examples of combinations, in particular for external topical administration (e.g. versus atopic dermatitis), include, for example, a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof together with an immunosuppressant, e.g. a calcineurin inhibitor such as pimecrolimus or tacrolimus. The immunosuppressant can in particular be an externally-topically administrable immunosuppressant such as pimecrolimus (e.g. pimecrolimus at ca. 1% w/w concentration in a topical composition such as a cream, and/or e.g. Elidel™) or tacrolimus (e.g. tacrolimus at from about 0.03% to about 0.1% w/w concentration in a topical composition such as an ointment, and/or e.g. Protopic™). The externally-topically administrable immunosuppressant can be administered or administrable in a external-topical composition separately from the compound or salt of the invention, or it can be contained with the compound of formula (I) or pharmaceutically acceptable salt in a combined externally-topically-administrable composition.
For external topical administration, e.g. versus an inflammatory and/or allergic skin disease such as atopic dermatitis or psoriasis, in a combination of the compound or salt of the invention together with an anti-infective agent, the anti-infective agent can include (e.g. be) an externally-topically-administrable antibacterial, such as mupiricin or a salt thereof (e.g. mupirocin calcium salt) (e.g. Bactroban™) or such as an externally-topically-administrable pleuromutilin antibacterial (e.g. retapamulin or a salt thereof, which can be present in about 1% w/w by weight of an externally-topically-administrable pharmaceutical composition, such as an ointment). Alternatively or additionally, for external topical administration, the anti-infective agent can include an externally-topically-administrable antifungal such as clotrimazole (e.g. at about 1% to about 10% w/w or at about 1% to about 2% w/w in a topical composition), or ketoconazole, or terbinafine (e.g. as HCl salt and/or at about 1% w/w).
For external topical administration, e.g. versus atopic dermatitis, a combination with an anti-itch compound may optionally be used.
The combinations referred to above may be presented for use in the form of a pharmaceutical composition and thus a pharmaceutical composition comprising a combination as defined above together with one or more pharmaceutically acceptable carriers and/or excipients represent a further aspect of the invention.
The individual compounds of such combinations may be administered either sequentially or simultaneously in separate or combined pharmaceutical composition.
In one embodiment, the combination as defined herein can be for simultaneous inhaled administration and is disposed in a combination inhalation device. Such a combination inhalation device is another aspect of the invention. Such a combination inhalation device can comprise a combined pharmaceutical composition for simultaneous inhaled administration (e.g. dry powder composition), the composition comprising all the individual compounds of the combination, and the composition being incorporated into a plurality of sealed dose containers mounted longitudinally in a strip or ribbon inside the inhalation device, the containers being rupturable or peel-openable on demand; for example such inhalation device can be substantially as described in GB 2,242,134 A (DISKUS™) and/or as described above. Alternatively, the combination inhalation device can be such that the individual compounds of the combination are administrable simultaneously but are stored separately (or wholly or partly stored separately for triple combinations), e.g. in separate pharmaceutical compositions, for example as described in PCT/EP03/00598 filed on 22 Jan. 2003, published as WO 03/061743 A1 (which discloses a medicament dispenser for use with plural elongate form medicament carriers, each having multiple distinct medicament dose portions carried thereby, e.g. as described in the claims thereof e.g. claim 1) and/or WO 2007/012871 A1 (which discloses a medicament dispenser for use with at least one medicament carrier carrying multiple distinct medicament portions, e.g. as described in the claims thereof e.g. claim 1).
The invention also provides a method of preparing a combination as defined herein,

- the method comprising either
- (a) preparing a separate pharmaceutical composition for administration of the individual compounds of the combination either sequentially or simultaneously, or
- (b) preparing a combined pharmaceutical composition for administration of the individual compounds of the combination simultaneously,
- wherein the pharmaceutical composition comprises the combination together with one or more pharmaceutically acceptable carriers and/or excipients.

The invention also provides a combination as defined herein, prepared by a method as defined herein.

Biological Test Methods

PDE 3, PDE 4B, PDE 4D, PDE 5, PDE 6 In Vitro Assay Methods

The biological activity of the compounds or salts of the invention can be measured in the assay methods shown below, or in generally similar or generally analogous assay methods.
Some of the Examples disclosed herein and encompassed within the invention are selective PDE4 inhibitors, i.e. they inhibit PDE4 (e.g. PDE4B) more strongly than they inhibit PDE3 and/or more strongly than they inhibit PDE5 and/or more strongly than they inhibit PDE6. It is to be recognised that such selectivity is not essential to the invention.

POSSIBLE PDE ENZYME SOURCES AND LITERATURE REFERENCES

Human recombinant PDE4B, in particular the 2B splice variant thereof (HSPDE4B2B), is disclosed in WO 94/20079 and also M. M. McLaughlin et al., “A low Km, rolipram-sensitive, cAMP-specific phosphodiesterase from human brain: cloning and expression of cDNA, biochemical characterisation of recombinant protein, and tissue distribution of mRNA”, J. Biol. Chem., 1993, 268, 6470-6476. For example, in Example 1 of WO 94/20079, human recombinant PDE4B is described as being expressed in the PDE-deficient yeast Saccharomyces cerevisiae strain GL62, e.g. after induction by addition of 150 uM CuSO₄, and 100,000×g supernatant fractions of yeast cell lysates are described for use in the harvesting of PDE4B enzyme.
Human recombinant PDE4D (HSPDE4D3A) is disclosed in P. A. Baecker et al., “Isolation of a cDNA encoding a human rolipram-sensitive cyclic AMP phoshodiesterase (PDE IV_D)”, Gene, 1994, 138, 253-256.
Human recombinant PDE5 is disclosed in K. Loughney et al., “Isolation and characterisation of cDNAs encoding PDE5A, a human cGMP-binding, cGMP-specific 3′,5′-cyclic nucleotide phosphodiesterase”, Gene, 1998, 216, 139-147.
PDE3 can be purified from bovine aorta as described by H. Coste and P. Grondin, “Characterisation of a novel potent and specific inhibitor of type V phosphodiesterase”, Biochem. Pharmacol., 1995, 50, 1577-1585.
PDE6 can be purified from bovine retina as described by: P. Catty and P. Deterre, “Activation and solubilization of the retinal cGMP-specific phosphodiesterase by limited proteolysis”, Eur. J. Biochem., 1991, 199, 263-269; A. Tar et al. “Purification of bovine retinal cGMP phosphodiesterase”, Methods in Enzymology, 1994, 238, 3-12; and/or D. Srivastava et al. “Effects of magnesium on cyclic GMP hydrolysis by the bovine retinal rod cyclic GMP phosphodiesterase”, Biochem. J., 1995, 308, 653-658.

Inhibition of PDE 3, PDE 4B, PDE 4D, PDE 5 or PDE 6 Activity: Radioactive Scintillation Proximity Assay (SPA)

The ability of compounds to inhibit catalytic activity at PDE4B or 4D (human recombinant), PDE3 (from bovine aorta), PDE5 (human recombinant) or PDE6 (from bovine retina) can optionally be determined by Scintillation Proximity Assay (SPA) in a 96-well format.
Test compounds (as a solution in DMSO, suitably about 2 microlitre (ul) volume of DMSO solution) are preincubated at ambient temperature (room temperature, e.g. 19-23° C.) in Wallac Isoplates (code 1450-514) with PDE enzyme in 50 mM Tris-HCl buffer pH 7.5, 8.3 mM MgCl₂, 1.7 mM EGTA, 0.05% (w/v) bovine serum albumin for 10-30 minutes (usually 30 minutes). The enzyme concentration is adjusted so that no more than 20% hydrolysis of the substrate defined below occurs in control wells without compound, during the incubation. For the PDE3, PDE4B and PDE4D assays, [5′,8-³H]Adenosine 3′,5′-cyclic phosphate (Amersham Pharmacia Biotech, code TRK.559; or Amersham Biosciences UK Ltd, Pollards Wood, Chalfont St Giles, Buckinghamshire HP8 4SP, UK) is added to give 0.05 uCi per well and about 10 nM final concentration. For the PDE5 and PDE6 assays, [8-³H]Guanosine 3′,5′-cyclic phosphate (Amersham Pharmacia Biotech, code TRK.392) is added to give 0.05 uCi per well and about 36 nM final concentration. Plates containing assay mixture, suitably approx. 100 ul volume of assay mixture, are mixed on an orbital shaker for 5 minutes and incubated at ambient temperature for 1 hour. Phosphodiesterase SPA beads (Amersham Pharmacia Biotech, code RPNQ 0150) are added (about 1 mg per well) to terminate the assay. Plates are sealed and shaken and allowed to stand at ambient temperature for 35 minutes to 1 hour (suitably 35 minutes) to allow the beads to settle. Bound radioactive product is measured using a WALLAC TRILUX 1450 Microbeta scintillation counter. For inhibition curves, 10 concentrations (e.g. 1.5 nM-30 uM) of each compound are assayed. Curves are analysed using ActivityBase and XLfit (ID Business Solutions Limited, 2 Ocean Court, Surrey Research Park, Guildford, Surrey GU2 7QB, United Kingdom) Results are expressed as pIC₅₀values.
In an alternative to the above radioactive SPA assay, PDE4B or PDE4D inhibition can be measured in the following Fluorescence Polarisation (FP) assay:

Inhibition of PDE4B or PDE4D Activity: Fluorescence Polarisation (FP) Assay

The ability of compounds to inhibit catalytic activity at PDE4B (human recombinant) or PDE4D (human recombinant) can optionally be determined by IMAP Fluorescence Polarisation (FP) assay (IMAP Explorer kit, available from Molecular Devices Corporation, Sunnydale, Calif., USA; Molecular Devices code: R8062) in 384-well format.
The IMAP FP assay is able to measure PDE activity in an homogenous, non-radioactive assay format. The FP assay uses the ability of immobilised trivalent metal cations, coated onto nanoparticles (tiny beads), to bind the phosphate group of Fl-AMP that is produced on the hydrolysis of fluorescein-labelled (Fl) cyclic adenosine mono-phosphate (Fl-cAMP) to the non-cyclic Fl-AMP form. Fl-cAMP substantially does not bind. Binding of Fl-AMP product to the beads (coated with the immobilised trivalent cations) slows the rotation of the bound Fl-AMP and leads to an increase in the fluorescence polarisation ratio of parallel to perpendicular light. Inhibition of the PDE reduces/inhibits this signal increase.
Test compounds (small volume, e.g. ca. 0.5 to 1 microlitres (ul), suitably ca. 0.5 ul, of solution in DMSO) are preincubated at ambient temperature (room temperature, e.g. 19-23° C.) in black 384-well microtitre plates (supplier: NUNC, code 262260) with PDE enzyme in 10 mM Tris-HCl buffer pH 7.2, 10 mM MgCl₂, 0.1% (w/v) bovine serum albumin, and 0.05% NaN₃for 10-30 minutes. The enzyme level is set by experimentation so that reaction is linear throughout the incubation. Fluorescein adenosine 3′,5′-cyclic phosphate (from Molecular Devices Corporation, Molecular Devices code: R7091) is added to give about 40 nM final concentration (final assay volume usually ca. 20-40 ul, suitably ca. 20 ul). Plates are mixed on an orbital shaker for 10 seconds and incubated at ambient temperature for 40 minutes. IMAP binding reagent (as described above, from Molecular Devices Corporation, Molecular Devices code: R7207) is added (60 ul of a 1 in 400 dilution in binding buffer of the kit stock solution) to terminate the assay. Plates are allowed to stand at ambient temperature for 1 hour. The Fluorescence Polarisation (FP) ratio of parallel to perpendicular light is measured using an Analyst™ plate reader (from Molecular Devices Corporation). For inhibition curves, 10 concentrations (e.g. 1.5 nM-30 uM) of each compound are assayed. Curves are analysed using ActivityBase and XLfit (ID Business Solutions Limited, 2 Ocean Court, Surrey Research Park, Guildford, Surrey GU2 7QB, United Kingdom). Results are expressed as pIC₅₀values.
In the FP assay, reagents can be dispensed using Multidrop™ (available from Thermo Labsystems Oy, Ratastie 2, PO Box 100, Vantaa 01620, Finland).
For a given PDE4 inhibitor, the PDE4B (or PDE4D) inhibition values measured using the SPA and FP assays can differ slightly.
Biological Data obtained for some of the Examples (PDE4B inhibitory activity, either as one reading (n=1) or as an average of 2 or more readings (n=2 or more) are generally as follows, based on measurements only, generally using SPA and/or FP assay(s) generally as described above or generally similar or generally analogous to those described above. In each of the SPA and FP assays, absolute accuracy of measurement is not possible, and the pIC₅₀readings given are generally thought to be accurate only up to very approximately ±0.5 of a log unit, depending on the number of readings made and averaged:
Examples 5, 7, 8, 13, 15 and 16 generally have PDE4B inhibitory activities in the range of pIC₅₀=about 8.8 (±about 0.5) to about 9.7 (±about 0.5), generally as measured using the FP assay generally as described above or a generally similar or generally analogous assay.
Emesis: Some known PDE4 inhibitors can cause emesis and/or nausea to greater or lesser extents, especially after systemic exposure e.g. after oral administration (e.g. see Z. Huang et al., Current Opinion in Chemical Biology, 2001, 5: 432-438, see especially pages 433-434 and refs cited therein). Therefore, it would be preferable, but not essential, if a PDE4 inhibitory compound or salt of the invention were to cause only limited or manageable emetic side-effects, e.g. after inhaled or parenteral or external-topical administration. Emetic side-effects can for example be measured by the emetogenic potential of the compound or salt when administered to ferrets or monkeys; for example the time to onset, extent, frequency and/or duration of vomiting, retching and/or writhing in ferrets or monkeys is optionally measured, after intratracheal or parenteral or intraperitoneal (or oral) administration of the PDE4 inhibitor compound or salt. See for example A. Robichaud et al., “Emesis induced by inhibitors of [PDE IV] in the ferret”, Neuropharmacology, 1999, 38, 289-297, erratum Neuropharmacology, 2001, 40, 465-465.
Other side effects: Some known PDE4 inhibitors can cause other side effects such as headache and/or other central nervous sytem (CNS-) mediated side effects; and/or gastrointestinal (GI) tract disturbances. Therefore, it would be preferable but not essential if a particular PDE4 inhibitory compound or salt of the invention were to cause only limited or manageable side-effects in one or more of these side-effect categories.

Other In Vitro Assays:

Other assays which may also be optionally used to further profile compounds or salts of the invention include the following.

Inhibition of TNF-α (TNF-alpha) Production in Human PBMC (Peripheral Blood Mononuclear Cell) Assay (MSD Technology)

This is an optional supplementary test, e.g. for potentially inhalably-administrable PDE4 inhibitors.
A 96-well plate (96 MicroWell™ Plates Nunclon™Δ-High Flange Design, Fisher Scientific UK, Bishop Meadow Road, Loughborough LE 11 5 RG, Leicestershire, UK) is prepared by initially adding to column 1 ca. 10 mM of test compound dissolved in DMSO. For a more potent compound, a more diluted solution in DMSO may be used. The compound is further diluted with DMSO into columns 2 to 9 by 8 successive 3-fold dilutions using the Biomek® FX Laboratory Automation Workstation (Beckman Coulter, Inc., 4300 N. Harbor Boulevard, P.O. Box 3100, Fullerton, Calif. 92834-3100, USA).
Column 10 is used as a DMSO negative control (High Signal, 0% response), whilst column 11, which contains 10 mM of the PDE4 inhibitor roflumilast, is used as a positive control (Low Signal, 100% response). About 1 μl (about 1 ul) of compound is transferred to the compound plate using the Biomek® FX.
PBMC cells (peripheral blood mononuclear cells) are prepared from heparinised human blood (using 1% v/v Heparin Sodium 1000 IU/ml Endotoxin Free, Leo Laboratories Ltd., Cashel Road, Dublin 12. Ireland, Cat No: PL0043/0149) from normal volunteers using the Accuspin™ System-Histopaque®-1077 essentially (Sigma-Aldrich Company Ltd., The Old Brickyard New Rd, Gillingham, Dorset SP8 4XT, UK). About 20 ml of blood is overlaid onto 15 ml Histopaque® in Accuspin™ tubes. The tube is then centrifuged at about 800 g for ca. 20 minutes. The cells are collected from the interface, washed by centrifugation (ca. 1300 g, ca. 10 minutes) and resuspended in RPMI1640 medium (Low endotoxin RPMI1640 medium, Cat No: 31870-025, Invitrogen Corporation Invitrogen Ltd, 3 Fountain Drive, Inchinnan Business Park, Paisley PA4 9RF, UK) containing 10% foetal calf serum, 1% L-glutamine (Invitrogen Corporation, Cat No: 25030024) and 1% penicillin/streptomycin (Invitrogen Corporation, Cat No: 15140-122). Viable cells are counted by trypan blue staining and diluted to 1×10⁶viable cells/ml. About 50 μl (about 50 ul) of diluted cells and about 75 μl (about 75 ul) of LPS (ca. 1 ng/ml final; Sigma Cat No: L-6386) are added to the compound plate, which is then incubated at 37° C., 5% CO₂, for 20 hours.
The supernatant is removed and the concentrations of TNF-α are determined by electrochemiluminescence assay using the Meso Scale Discovery (MSD) technology (Meso Scale Discovery, 9238 Gaither Road, Gaithersburg, Md. 20877, USA). See the “TNF-α (TNF-alpha) MSD Assay” described below for typical details.
Results can be expressed as pIC50 values for inhibition of TNF-α (TNF-alpha) production in PBMCs, and it should be appreciated that these results can be subject to a possibly-large variability or error.

Inhibition of TNF-α (TNF-Alpha) Production in Human PBMC (Peripheral Blood Mononuclear Cell) Assay (IGEN Technology)

This is an optional supplementary test, e.g. for potentially inhalably-administrable PDE4 inhibitors.
Test compounds are prepared as a ca. 10 mM stock solution in DMSO and a dilution series prepared in DMSO with 8 successive 3-fold dilutions, either directly from the 10 mM stock solution or from a more dilute solution in DMSO. The compound is added to assay plates using a Biomek Fx liquid handling robot.
PBMC cells (peripheral blood mononuclear cells) are prepared from heparinised human blood from normal volunteers by centrifugation on histopaque at ca. 100 g for ca. 30 minutes. The cells are collected from the interface, washed by centrifugation (ca. 1300 g, ca. 10 minutes) and resuspended in assay buffer (RPMI 1640 containing 10% foetal calf serum, 1% L-glutamine and 1% penicillin/streptomycin) at 1×10⁶cells/ml. Ca. 50 μl (ca. 50 ul) of cells are added to microtitre wells containing ca. 0.5 or ca. 1.0 μl (ul) of an appropriately diluted compound solution. Ca. 75 μl (ul) of LPS (lipopolysaccharide) (ca. 1 ng/ml final) is added and the samples are incubated at 37° C., 5% CO₂, for 20 hours.
The supernatant is removed and the concentrations of TNF-α are determined by electrochemiluminescence assay using the IGEN technology or by ELISA (see below).
Results can be expressed as pIC50 values for inhibition of TNF-α (TNF-alpha) production in PBMCs, and it should be appreciated that these results can be subject to a possibly-large variability or error.

Inhibition of TNF-α (TNF-Alpha) Production in Human Whole Blood

This is an optional supplementary test. For example, as the assay may measure the effect of PDE4 inhibitors after loss by protein binding, it might possibly be relevant to externally-topically-administrable PDE4 inhibitors as protein-binding-loss of compound is possible during transport through the skin.
Test compounds are prepared as a ca. 10 mM stock solution in DMSO and a dilution series prepared in DMSO with 8 successive 3-fold dilutions, either directly from the 10 mM stock solution or from a more dilute solution in DMSO. The compound is added to assay plates using a Biomek Fx liquid handling robot.
Heparinised blood drawn from normal volunteers is dispensed (ca. 100 μl=ca. 100 ul) into microtitre plate wells containing ca. 0.5 or ca. 1.0 μl (ul, microlitres) of an appropriately diluted test compound solution. After ca. 1 hr incubation at ca. 37° C., 5% CO₂, ca. 25 μl (ca. 25 ul) of LPS (lipopolysaccharide) solution (S. typhosa) in RPMI 1640 (containing 1% L-glutamine and 1% Penicillin/streptomycin) is added (ca. 50 ng/ml final). The samples are incubated at ca. 37° C., 5% CO₂, for ca. 20 hours, and ca. 100 μl (ca. 100 ul) physiological saline (0.138% NaCl) is added, and diluted plasma is collected using a Platemate or Biomek FX liquid handling robot after centrifugation at ca. 1300 g for ca. 10 min. Plasma TNF-α content is determined by electrochemiluminescence assay using the MSD technology (see below), the IGEN technology (see below) or by enzyme linked immunosorbant assay (ELISA) (see below).
Results can be expressed as pIC50 values for inhibition of TNF-α (TNF-alpha) production in Human Whole Blood, and it should be appreciated that these results can be subject to a possibly-large variability or error.

TNF-α (TNF-alpha) MSD Assay

Using the Biomek FX, 25 μl (25 ul) of MSD Human Serum Cytokine Assay Diluent (Meso Scale Discovery, 9238 Gaither Road, Gaithersburg, Md. 20877) is added to a 96-well High-Bind MSD plate pre-coated with anti-hTNF alpha capture antibody (MA6000) and then incubated for 24 hours at 4° C. to prevent non-specific binding. About 20 μl (ul) of supernatant from the PBMC plate or about 40 μl (ul) of supernatant from the whole blood (WB) plate are then transferred from columns 1-11 to columns 1-11 of the MSD plate using the Biomek FX. About 20 μl (ul) of TNF-α standard (Cat No. 210-TA; R&D Systems Inc., 614 McKinley Place NE, Minneapolis, Minn. 55413, USA) are added to column 12 of the MSD plate to generate a standard calibration curve (about 0 to 30000 pg/ml final).
For the Whole Blood assay, plates are washed after 2 hours shaking with a Skanwasher 300 version B (Skatron Instruments AS. PO Box 8, N-3401 Lier, Norway). About 40 μl (ul) of diluted sulfo-TAG antibody (ca. 1 μg/ml final) is added, the plates are shaken at room temperature for 1 hours, and the plates washed again as above. About 150 μl (ul) of Read Buffer T (2×) is added to the plates, which are then read on a MSD Sector 6000.
For the PBMC assay, about 20 μl (ul) of diluted sulfo-TAG antibody (ca. 1 μg/ml final) is added to each well, and the plates/wells are shaken at room temperature for 2 hours. Finally, about 90 μl (ul) of MSD Read Buffer P (diluted to 2.5 times with distilled water) is added and the plates are read on a MSD Sector 6000.

Data Analysis

Data analysis is performed with ActivityBase/XC50 module (ID Business Solutions Ltd., 2 Occam Court, Surrey Research Park, Guildford, Surrey, GU2 7QB, UK). Data are normalized and expressed as % inhibition using the formula 100*((U−C1)/(C₂−C₁)) where U is the unknown value, C1 is the average of the high signal (0%) control wells (column 10), and C2 is the average of the low signal (100%) control wells (column 11). Curve fitting is performed with the following equation: y=A+((B−A)/(1+(10̂x/10̂C)̂D)), where A is the minimum response, B is the maximum response, C is the log 10(IC50), and D is the Hill slope. The results for each compound are recorded as pIC50 values (−C in the above equation).

TNF-α (TNF-Alpha) IGEN Assay

Ca. 50 μl supernatant from either whole blood or PBMC assay plates is transferred to a 96 well polypropylene plate. Each plate also contains a TNF-α standard curve (ca. 0 to 30000 pg/ml: R+D Systems, 210-TA). Ca. 50 μl (ul) of streptavidin/biotinylated anti-TNF-α antibody mix, ca. 25 μl ruthenium tagged anti-TNF-α monoclonal and ca. 100 μl PBS containing 0.1% bovine serum albumin are added to each well and the plates are sealed and shaken for ca. 2 hours before being read on an IGEN instrument.

TNF-α (TNF-Alpha) ELISA Assay (Enzyme Linked Immunosorbant Assay)

Human TNF-α can be assayed using a commercial ELISA assay kit (AMS Biotechnology, 211-90-164-40) according to the manufacturers' instructions but with TNF-α calibration curves prepared using Pharmingen TNF-α (cat. No. 555212).

In Vivo Biological Assays

The in vitro enzymatic PDE4B inhibition assay(s) described above or generally similar or analogous assays should be regarded as being the primary test(s) of biological activity. However, some additional in vivo biological tests, which are optional only, and which are not an essential measure of activity, efficacy or side-effects, and which are believed not to have been carried out for the present Examples, are described below.

In Vivo Assay 1. LPS Induced Pulmonary Neutrophilia in Rats: Effect of Intratracheally Administered PDE4 Inhibitors

This assay is an animal model of acute inflammation in the lung—specifically neutrophilia induced by lipopolysaccharide (LPS)— and allows the study of putative inhibition of such neutrophilia (anti-inflammatory effect) by an intratracheally (i.t.) administered PDE4 inhibitor (“drug”). The PDE4 inhibitors are suitably in dry powder, aqueous solution or aqueous suspension form. I.t. administration is one model of inhaled administration, allowing topical delivery to the lung.
Animals: Male CD (Sprague Dawley Derived) rats supplied by Charles River, United Kingdom are housed in groups of 5 rats per cage, acclimatised after delivery for at least 7 days with bedding/nesting material regularly changed, fed on SDS diet R1 pelleted food given ad lib, and supplied with daily-changed pasteurised animal grade drinking water.
Device for dry powder administration: For these studies, a Penn Century DP-4 dry powder intratracheal (i.t.) delivery device (insufflator) is used for administration of a dry powder blend of vehicle (inhalation grade lactose) and the PDE4 inhibitor compound or salt of the invention (“drug”). Each device is numbered and the sample loading chamber is unscrewed from the main device and weighed. The i.t. delivery needle is also weighed. The drug+lactose blend or inhalation grade lactose (vehicle control) is then added to the sample chamber and this is then re-weighed. The sample chamber is fitted back on to the main device to prevent any drug being lost. This procedure is repeated for all of the Penn century devices to be used in the study (one separate device for each animal). After dosing to the animals, the sample chambers and needles are re-weighed in order to determine the amount of sample that was expelled from the device.
Device for aqueous solution administration: A blunt dosing needle, whose forward end is slightly angled to the needle axis, is used, with a flexible plastic portex canula inserted into the needle. The portex cannula is inserted into the lumen of the blunt stainless steel dosing needle and this is carefully inserted into the back of the animal's throat and into the trachea via the larynx. A known volume (200 microlitres) of the vehicle (0.2% Tween 80™ in saline) or of the solution (or suspension) drug composition is administered into the trachea using a plastic syringe that is attached to the portex cannula and dosing needle. A new internal cannula is used for each different drug group. After dosing, the needle is removed from the trachea and the animals are removed from the table and continually observed until they recover from the effects of anaesthesia. The animals are then returned to the holding cages and given free access to food and water, and are observed and any unusual behavioural changes noted. (Aqueous suspensions can be handled generally similarly.)
Drugs and Materials: Lipopolysaccharide (LPS) (Serotype:0127:B8, e.g. from Sigma, UK; e.g. L3129 prepared by phenol extraction) is dissolved in phosphate-buffered saline (PBS).
For dry powder, aqueous solution or aqueous suspension administration, PDE4 inhibitors are preferably used in size-reduced (e.g. micronised) form, for example according to the Micronisation Example(s) disclosed herein.
For dry powder administration of the drug, the PDE4 inhibitor compound or salt of the invention (drug) is administered as a dry powder blended with inhalation-grade (respiratory-grade) lactose, i.e. as a dry powder composition. The target quantity of dry powder composition administered i.t. to each animal is 2 mg. This remains constant throughout the studies. To achieve different doses, blends of the drug dry powder and lactose, containing different concentrations of the PDE4 inhibitor compound or salt of the invention (drug), are prepared. The following dry powder blends, or generally similar blends with generally analogous but nonidentical concentrations, are generally used for these studies:

- Blend 1: 0.1667% w/w of drug in lactose, which can e.g. be used to dose rats at about 10 μg/kg (about 10 ug/kg), depending on the bodyweight of the rats used (e.g. ca. 300-350 g bodyweight);
- Blend 2: 0.5% w/w of drug in lactose, which can e.g. be used to dose rats at about 30 μg/kg (about 30 ug/kg), depending on the bodyweight of the rats used (e.g. ca. 300-350 g bodyweight);
- Blend 3: 1.667% w/w of drug in lactose, which can e.g. be used to dose rats at about 100 μg/kg (about 100 ug/kg), depending on the bodyweight of the rats used (e.g. ca. 300-350 g bodyweight);
- Blend 4: 5% w/w of drug in lactose, which can e.g. be used to dose rats at about 300 μg/kg (about 300 ug/kg), depending on the bodyweight of the rats used (e.g. ca. 300-350 g bodyweight).

For dry powder administration of the drug, one suitable inhalation-grade lactose that is typically used is: lactose monohydrate; and/or lactose having about 10% fines (i.e. has about 10% of material under 15 um (15 micron) particle size, measured by Malvern particle size). Other inhalation-grade lactoses might have e.g. from about 7% to about 11% fines.
For aqueous solution compositions of the drug, a composition of 0.2% Tween 80™ (e.g. available from Sigma, e.g. 073K 00643) in phosphate buffered saline (PBS) is prepared and used as the vehicle. The Sigma catalogue 2004-2005 and The Handbook of Pharmaceutical Excipients (HPE) 4th edition 2003 pp. 479-483 define Tween 80™ as a brand of polysorbate 80 (according to HPE, polysorbate 80 is also named polyoxyethylene 20 sorbitan monooleate, i.e. having been copolymerised with about 20 moles of ethylene oxide for each mole of sorbitol and/or sorbitol anhydrides used).
Solution compositions are prepared by adding the required volume of 0.2% Tween 80™ in PBS to the pre-weighed PDE4 inhibitor compound or salt of the invention (drug). The average weight of the rats generally used in these studies is approximately 350 g; the i.t. solution dose volume is 200 microlitres. Thus, for a target dose of 100 μg/kg (100 ug/kg), a 0.175 mg/ml solution of the drug is prepared. Lower concentrations are achieved by preparing serial dilutions from the 0.175 mg/ml stock solution concentration. All solutions were prepared immediately prior to dosing. The formulation is usually sonicated, e.g. for approximately 2-15 minutes e.g. ca. 2 minutes, prior to use and is observed to be a solution (if it is a solution) by visual examination.
Similar to aqueous solutions, aqueous suspensions of a drug can be prepared by adding the required volume of vehicle to the pre-weighed drug; the vehicle used can for example be saline alone or preferably a mixture of saline/Tween™ (e.g. 0.2% Tween 80™ in phosphate buffered saline). The aqueous suspension is usually sonicated, e.g. for about 10-15 minutes, prior to use.
Preparation, and dosing with PDE 4 inhibitor: Rats are anaesthetised by placing the animals in a sealed Perspex chamber and exposing them to a gaseous mixture of isoflourane (4.5%), nitrous oxide (3 litres/minute) and oxygen (1 litre/minute). Once anaesthetised, the animals are placed onto a stainless steel i.t. dosing support table. They are positioned on their back at approximately a 35° angle. A light is angled against the outside of the throat to highlight the trachea. The mouth is opened and the opening of the upper airway visualised. The procedure varies for aqueous solution and dry powder administration of PDE4 inhibitors as follows:
Dosing with an aqueous solution: A portex cannula is introduced via a blunt metal dosing needle that has been carefully inserted into the rat trachea. The animals are intratracheally dosed with vehicle or PDE4 inhibitor via the dosing needle with a new internal canula used for each different drug group. The formulation is slowly (ca. 5 seconds) dosed into the trachea using a syringe attached to the dosing needle. The procedure with an aqueous suspension is generally similar.
Dosing with a Dry Powder: The intratracheal dosing device (a Penn Century dry powder insufflator, DP-4) is inserted into the rat trachea up to a pre-determined point established to be located approximately 1 cm above the primary bifurcation. Two×3 ml of air is delivered using the Penn Century dry powder insufflator device by depressing a plastic syringe (ideally coinciding with the animal inspiring), aiming to expel the entire drug quantity from the tap. After dosing, the device is removed from the airway, and then is stored in an upright position in a sealed plastic bag. At a later stage, the device is re-weighed to determine the quantity of dry powder delivered.
After dosing with either aqueous solution (or wet suspension) or dry powder, the animals are removed from the table and observed constantly until they have recovered from the effects of anaesthesia. The animals are returned to the holding cages and given free access to food and water; they are observed and any unusual behavioural changes noted.
Exposure to LPS: About 2 hours after i.t. dosing with vehicle control or the PDE4 inhibitor, the rats are placed into sealed Perspex containers and exposed to an aerosol of LPS (nebuliser concentration ca. 150 μg.ml⁻¹=ca. 150 ug/ml) for ca. 15 minutes. Aerosols of LPS are generated by a nebuliser (DeVilbiss, USA) and this is directed into the Perspex exposure chamber. Following the 15-minute LPS-exposure period, the animals are returned to the holding cages and allowed free access to both food and water.
In an alternative embodiment, the rats can be exposed to LPS less than 2 hours (e.g. about 30 minutes) after i.t. dosing.
In another alternative embodiment, the rats can be exposed to LPS more than 2 hours (e.g. ca. 4 hours to ca. 36 hours, such as 4 hours, 6 hours, 8 hours, 12 hours, 18 hours, 24 hours or 36 hours, in particular 4 hours or 12 hours) after i.t. dosing by vehicle or PDE4 inhibitor, to test whether or not the PDE4 inhibitor has a long duration of action (which is preferable but not essential).
Bronchoalveolar lavage: About 4 hours after LPS exposure the animals are killed by overdose of sodium pentobarbitone (i.p.). The trachea is cannulated with polypropylene tubing and the lungs are lavaged (washed out) with 3×5 ml of heparinised (25 units/ml) phosphate buffered saline (PBS).
Neutrophil cell counts: The Bronchoalveolar lavage (BAL) samples are centrifuged at ca. 1300 rpm for ca. 7 minutes. The supernatant is removed and the resulting cell pellet resuspended in ca. 1 ml PBS. A cell slide of the resuspension fluid is prepared by placing ca. 100 μl (ca. 100 ul) of resuspended BAL fluid into cytospin holders and then is spun at ca. 5000 rpm for ca. 5 minutes. The slides are allowed to air dry and then stained with Leishmans stain (ca. 20 minutes) to allow differential cell counting. The total cells are also counted from the resuspension. From these two counts, the total numbers of neutrophils in the BAL are determined. For a measure of PDE4-inhibitor-induced inhibition of neutrophilia, a comparison of the neutrophil count in rats treated with vehicle and rats treated with PDE4 inhibitors is conducted.
By varying the dose of the PDE4 inhibitor used in the dosing step (e.g. 0.3 or 0.1 mg of PDE4 inhibitor per kg of body weight, down to e.g. 0.01 mg/kg), a dose-response curve can be generated, and thence an ED₅₀value. The ED₅₀value is typically the dose required to achieve 50% of the maximum level of inhibition achievable for that particular PDE4 inhibitor (drug) in the particular composition used in that particular study. The ED₅₀value is not usually the dose required for 50% inhibition of neutrophilia.

In Vivo Assay 2 LPS Induced Nasal Neutrophilia in Rats: Effect of Intranasally Administered PDE4 Inhibitors

This assay is an animal model of acute inflammation in the nose—specifically neutrophilia induced by lipopolysaccharide (LPS)— and allows the study of putative inhibition of such neutrophilia (anti-inflammatory effect) by an intranasally (i.n.) administered PDE4 inhibitor (“drug”). The PDE4 inhibitor is preferably in the form of an aqueous suspension or aqueous solution. Bolus, i.n. administration allows topical delivery to the nose.
Animals: Male CD rats (Sprague Dawley derived), weighing between 300-350 g are supplied by Charles River, UK and transported to the test site. On arrival at the test site, the animals are housed in groups of 4 or 5 per cage and complete a minimum acclimatisation period of 7 days. The animals are housed in solid bottomed cages using grade 8 sawdust. The bedding and nesting materials are changed 3 times per week. Diet comprises SDS diet R1 pelleted food given ad lib. Pasteurised animal grade drinking water is supplied and changed daily.

Drugs and Materials

Lipopolysaccharide (Serotype: 0127:B8, e.g. available from Sigma, UK; e.g. L3129 prepared by phenol extraction) is used for all studies and is dissolved in phosphate-buffered saline (PBS).
Tween 80™ (e.g. available from Sigma e.g. 023K 01575). A mixture of 0.2% Tween 80™ in phosphate buffered saline (PBS) is prepared as vehicle for solution compositions. The Sigma catalogue 2004-2005 and The Handbook of Pharmaceutical Excipients (HPE) 4th edition 2003 pp. 479-483 define Tween 80™ as a brand of polysorbate 80 (according to HPE, polysorbate 80 is also named polyoxyethylene 20 sorbitan monooleate, i.e. having been copolymerised with about 20 moles of ethylene oxide for each mole of sorbitol and/or sorbitol anhydrides used).
The PDE4 inhibitor compound or salt of the invention (“drug”) is preferably used in size-reduced (e.g. micronised) form, for example according to the Micronisation Example(s) disclosed herein.
A solution of compound (0.7 mg/ml) is generally prepared by adding 0.2% Tween 80™ in phosphate buffered saline (PBS) to a pre-weighed micronised sample of the drug. The solution composition is sonicated, e.g. for approximately 2 min, and is observed to be a solution (if it is a solution) by visual assessment. A fixed volume of 50 microlitres (25 microlitres into each nostril) of either the drug-containing solution composition or a saline/Tween 80™ vehicle is administered to all animals. Each animal weighs, on average, 350 g. To achieve a dose of 100 μg/kg (100 ug/kg), each animal receives a total of 35 μg (35 ug) of the drug. The dose volume is 50 microlitres (25 microlitres to each nostril), and therefore a concentration of 35 μg (ug) per 50 microlitres (0.7 mg/ml) is prepared. To achieve lower dose concentrations, serial dilutions are prepared in saline/Tween 80™.
Intranasal dosing with the PDE4 inhibitor (drug): Rats are anaesthetised by placing the animals in a sealed Perspex chamber and exposing them to a gaseous mixture of isofluorane (5%), nitrous oxide (2 L/min) and oxygen (1 L/min). Once anaesthetised, the animals are i.n. dosed with vehicle or PDE4 inhibitor aqueous compositions using a 10-100-microlitre-range Gilson pipette and plastic disposable tip. A volume of 25 microlitres is administered into each nostril by carefully inserting the pipette tip into the nostril and dispensing the required volume. When the dosing procedure is completed, the animal is returned to the cage and observed at regular intervals until it had recovered from the effects of the anaesthetic.
Exposure to LPS: Thirty minutes after i.n. dosing with vehicle or PDE4 inhibitor, the rats are anaesthetised as previously described and a 25 microlitres of a solution of LPS (175 μg/kg=175 ug/kg) is administered into each nostril using the same technique described for dosing of drug or vehicle. When the dosing procedure is completed, the animal is returned to the cage and observed at regular intervals until it had recovered from the effects of the anaesthetic.
Nasal Lavage Four hours after LPS exposure, the animals are euthanased by overdose of sodium pentobarbitone (i.p.). The trachea is exposed and a small incision made approximately 1 cm below the larynx. A polypropylene cannula is inserted into the trachea towards the larynx and into the upper airway. The nasal cavity is then lavaged with 15 ml of heparinised (10 units/ml) phosphate buffered saline. The lavage fluid is collected in a 20 ml plastic sterilin tube which is positioned against the nostrils.
Cell Counts The nasal lavage samples are centrifuged at 1300 rpm for 7 minutes. The supernatant is removed and the resulting cell pellet is resuspended in 0.5 ml PBS. A cell slide of the resuspension fluid is prepared by placing 75 microlitres of resuspended nasal lavage fluid into cytospin holders and then spun at 500 rpm for 5 min. The slides are allowed to air dry and then stained with Leishmans stain (20 minutes) to allow differential cell counting. The total cells are also counted from the resuspension. From these two counts, the total numbers of neutrophils in the nasal lavage fluid is determined. For a measure of PDE4-inhibitor-induced inhibition of neutrophilia, a comparison of the neutrophil count in rats treated with vehicle and rats treated with the PDE4 inhibitor is conducted. By varying the dose of the PDE4 inhibitor used in the dosing step (e.g. 0.3 or 0.1 mg of PDE4 inhibitor per kg of body weight, down to e.g. 0.01 mg/kg), a dose-response curve can be generated, and thence an ED₅₀value.

In Vivo Assay A:

Activity of Topically-Applied Compounds in a Pig Model of Atopic Dermatitis: Effect of Compounds, Applied by Skin Topical Administration, on the Dinitrofluorobenzene (DNFB)-Induced Delayed Type Hypersensitivity (DTH) Response in Pigs

General Study Design:

The pig DTH (delayed type hypersensitivity) model of contact hypersensitivity utilizes the Th2-mediated inflammatory response in pig skin to mimic the pathology of atopic dermatitis in humans. The model measures the potential anti-inflammatory effect of compounds, topically-applied to the skin, on the acute DTH (delayed type hypersensitivity) response in castrated male Yorkshire pigs.
In general in the assay, pigs (domestic Yorkshire pigs, 15-18 kg at time of sensitization, castrated males) are first sensitized by topical application of ca. 10% (w/v) dinitrofluorobenzene (DNFB) dissolved in DMSO:acetone:olive oil (ca. 1:5:3) (ca. 40 mg DNFB, 400 microlitre solution total) to the ears (outer) and groin (inner). The pigs are then challenged 12 days later with ca. 0.6% (w/v) DNFB applied to randomized sites on the shaved back of the pigs (ca. 90 micrograms/site; sites are identified and numbered by grid made with marking pen).
On the day of challenge, the treatments are performed at the challenge sites at about 2 hours prior to and about 6 hours after challenge (for DMSO/acetone solutions/suspensions containing the PDE4 inhibitor, to maximize exposure to drug), or at about 30 minutes after and about 6 hours after challenge (for topical ointments or creams containing the PDE4 inhibitor, representing a more clinically relevant treatment protocol).
One day (about 24 hrs) after challenge, and optionally again at ca. 48 hrs post challenge, test sites are visually evaluated for intensity and extent of erythema by measuring the diameter of the reaction at its widest point and assigning scores of 0 to 4 for each of erythema intensity and erythema extent. Induration (a measure of swelling) is also scored 0 to 4. Scores for erythema intensity, erythema extent and induration are assigned according to the following criteria: Intensity of Erythema: 0=normal, 1=minimal, barely visible, 2=mild, 3=moderate, 4=severe. Extent of Erythema (not raised): 0=no edema, 1=macules of pin head size, 2=lentil sized macules, 3=confluent macules, 4=diffuse over entire site. Induration (palpable): 0=normal, I=nodules of pin head size, 2=doughy lentil sized nodules, 3=confluent firm nodules, 4=diffuse hard lesion. The summed visual score at ca. 24 hours includes the individual scores for erythema intensity, erythema extent, and induration; so the maximal summed score for each site would be 12. High summed scores can generally indicate a high inflammatory response. Visual scores are subject to some inaccuracy/error.
Differences in the summed score between adjacent control (placebo) and treatment sites on the grids are calculated. This difference value is then used to determine the percent inhibition compared to the summed score for the control (placebo) sites. The more negative the difference value, the greater the calculated inhibition. Percent inhibition of (percent inhibition compared to) the mean summed score can be calculated.
About 24 hours after challenge, treatment sites can optionally also be visually evaluated for lesion area.

EXAMPLES

The various aspects of the invention will now be described by reference to the following examples. These examples are merely illustrative and are not to be construed as a limitation of the scope of the present invention.
In this section, “Intermediates” can represent syntheses of intermediate compounds intended for use in the synthesis of one or more of the “Examples”, and/or “Intermediates” can represent syntheses of intermediate compounds which can possibly be used in the synthesis of compounds of formula (I) or salts thereof. “Examples” are generally examples of compounds or salts of the invention, for example compounds of formula (I) or salts thereof.
Abbreviations used herein:

AcOH acetic acid
Ac₂O acetic anhydride
BEMP 2-t-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphazine
BOC₂O di tert-butyl carbonate
DMSO dimethyl sulfoxide
DCC N,N′-dicyclohexylcarbodiimide
DCM dichloromethane
DMF dimethyl formamide
DIPEA diisopropylethyl amine (ⁱPr₂NEt)
EDC 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride
EtOAc ethyl acetate
Et₂O diethyl ether
Et₃N triethylamine
EtOH ethanol
HATU O-(7-Azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate; also named O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate
HBTU O-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate
HOBT hydroxybenzotriazole=1-hydroxybenzotriazole
IPA isopropanol (isopropyl alcohol)
Lawesson's reagent 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulphide
LPS lipopolysaccharide
MeCN acetonitrile
MeOH methanol
MDAP mass directed autoprep HPLC
NMP 1-methyl-2-pyrrolidinone (also named 1-methyl-2-pyrrolidone or N-methyl-2-pyrrolidinone)
PyBOP (Benzotriazol-1-yloxy)-trispyrrolidinophosphonium hexafluorophosphate
TBME tert-butyl methyl ether
TMS tetramethylsilane
THF Tetrahydrofuran
TFA Trifluoroacetic acid
HPLC high performance liquid chromatography
h hours
min minutes
LCMS or LC/MS liquid chromatography/mass spectroscopy
NMR nuclear magnetic resonance (in which: s=singlet, d=doublet, t=triplet, q=quartet, dd=doublet of doublets, m=multiplet, H=no. of protons)
SPE solid phase extraction. Unless otherwise specified, the solid phase is usually silica gel. Aminopropyl SPE, if used, typically refers to a silica SPE column with aminopropyl residues immobilised on the solid phase (eg. IST Isolute™ columns). It is thought that compounds isolated by SPE are usually isolated as the free base.
SCX solid phase extraction (SPE) column with benzene sulfonic acid residues immobilised on the solid phase (eg. IST Isolute™ columns). When eluting with ammonia/methanol, it is thought that compounds isolated by SCX are usually in the free base form.
TLC thin layer chromatography
T_RETor R_Tretention time (e.g. from LCMS)
T_intinternal temperature of the reaction mixture
T_maxmaximum internal temperature, e.g. during an addition
Room temperature (ambient temperature): this is usually in the range of about 18 to about 25° C.

General Experimental Details

Machine Methods used herein:

LCMS (Liquid Chromatography/Mass Spectroscopy)

Waters ZQ mass spectrometer operating in positive ion electrospray mode, mass range 100-1000 amu.
UV wavelength: 215-330 nm
Column: 3.3 cm×4.6 mm ID (internal diameter), 3 μm (3 micrometres) ABZ+PLUS
Flow Rate: 3 ml/min
Injection Volume: 5 μl (5 microlitres)
Solvent A: 0.05% v/v solution of formic acid in a mixture of [95% acetonitrile and 5% water]
Solvent B: aqueous solution of [0.1% v/v formic acid+10 mMolar ammonium acetate]
Gradient: Mixtures of Solvent A and Solvent B are used according to the following gradient profiles (expressed as % Solvent A in the mixture): 0% A/0.7 min, 0-100% A/3.5 min, 100% A/1.1 min, 100-0% A/0.2 min.
It should be noted that retention times (T_RET) quoted herein are inherently variable (e.g. the variability can be about +/−0.2 min or more.). Variability can arise e.g. when samples are run on different Waters machines, or on the same Waters machine at different times of day or under slightly different conditions, even when the same type of column and identical flow rates, injection volumes, solvents and gradients are used.

Mass Directed Automated Preparative HPLC Column, Conditions and Eluent Method A (Eluent Containing Formic Acid)

The preparative HPLC column generally used is a Supelcosil ABZplus (10 cm×2.12 cm internal diameter; particle size 5 μm=5 micrometres). A mass spectrometer attached to the end of the column can detect peaks arising from eluted compounds.
UV detection wavelength: 200-320 nm
Flow rate: 20 ml/min
Injection Volume: 0.5 to 1.0 ml
Solvent A: 0.1% v/v aqueous formic acid solution
Solvent B: 0.05% v/v solution of formic acid in a mixture of [95% acetonitrile and 5% water]
Gradient systems: mixtures of Solvent A and Solvent B are used according to a choice of 5 generic gradient profiles (expressed as % Solvent B in the mixture), ranging from a start of 0 to 50% Solvent B, with all finishing at 100% Solvent B to ensure total elution.
It is thought that compounds isolated by this method are usually isolated as formate salts.

Mass Directed Automated Preparative HPLC Column, Conditions and Eluent Method B (Eluent Containing Trifluoroacetic Acid)

The preparative HPLC column generally used is a C18 column (10 cm×2.12 cm internal diameter; particle size 5 μm=5 micrometres). A mass spectrometer attached to the end of the column can detect peaks arising from eluted compounds.
UV detection wavelength: 200-320 nm
Flow rate: 20 ml/min
Injection Volume: 0.5 to 1.0 ml
Solvent A: 0.1% v/v aqueous trifluoroacetic acid solution
Solvent B: solution of 0.1% v/v trifluoroacetic acid in acetonitrile
Gradient systems: mixtures of Solvent A and Solvent B are used according to a choice of 5 generic gradient profiles (expressed as % Solvent B in the mixture), ranging from a start of 0 to 50% Solvent B, with all finishing at 100% Solvent B to ensure total elution.
It is thought that compounds isolated by this method are usually isolated as trifluoroacetate salts.

Mass Directed Automated Preparative HPLC Column, Conditions and Eluent Method C (Eluent Containing Trifluoroacetic Acid)

The preparative HPLC column generally used is a C18 column (10 cm×2.12 cm internal diameter; particle size 5 μm=5 micrometres). A mass spectrometer attached to the end of the column can detect peaks arising from eluted compounds.
UV detection wavelength: 210-254 nm
Flow rate: 20 ml/min
Injection Volume: 0.5 to 1.0 ml
Solvent A: 0.1% v/v aqueous trifluoroacetic acid solution
Solvent B: solution of 0.1% v/v trifluoroacetic acid in acetonitrile
Gradient systems: mixtures of Solvent A and Solvent B are used according to a choice of 5 generic gradient profiles (expressed as % Solvent B in the mixture), ranging from a start of 0 to 50% Solvent B, with all finishing at 100% Solvent B to ensure total elution.
It is thought that compounds isolated by this method are usually isolated as trifluoroacetate salts.

‘Hydrophobic Frit’

This generally refers to a Whatman PTFE filter medium (frit), pore size 5.0 μm (5.0 micrometres), housed in a polypropylene tube.
Evaporation of Product Fractions after Purification
Reference to column chromatography, SPE and preparative HPLC purification includes evaporation of the product containing fractions to dryness by an appropriate method.

Celite

References to celite generally refer to the filter agent Celite 545 (e.g. available from Aldrich).

Intermediates and Examples

Reagents not detailed in the text below are usually commercially available from chemicals suppliers, e.g. established suppliers such as Sigma-Aldrich. The addresses and/or contact details of the suppliers for some of the starting materials mentioned in the Intermediates and Examples below or the Assays above, or suppliers of miscellaneous chemicals in general, are as follows:

A B Chem, Inc., 547 Davignon, Dollard-des-Ormeaux, Quebec, H9B 1Y4, Canada
ABCR GmbH & CO. KG, P.O. Box 21 01 35, 76151 Karlsruhe, Germany
ACB Blocks Ltd; Kolokolnikov Per, 9/10 Building 2, Moscow, 103045, Russia
Aceto Color Intermediates (catalogue name), Aceto Corporation, One Hollow Lane, Lake Success, N.Y., 11042-1215, USA
Acros Organics, A Division of Fisher Scientific Company, 500 American Road, Morris Plains, N.J. 07950, USA
Aldrich (catalogue name), Sigma-Aldrich Company Ltd., Dorset, United Kingdom, telephone: +44 1202 733114; Fax: +44 1202 715460; ukcustsv@eurnotes.sial.com; or
Aldrich (catalogue name), Sigma-Aldrich Corp., P.O. Box 14508, St. Louis, Mo. 63178-9916, USA; telephone: +1-314-771-5765; fax: +1-314-771-5757; custserv@sial.com; or
Aldrich (catalogue name), Sigma-Aldrich Chemie GmbH, Munich, Germany; telephone: +49 89 6513 0; Fax: +49 89 6513 1169; deorders@eurnotes.sial.com.
Alfa Aesar, A Johnson Matthey Company, 30 Bond Street, Ward Hill, Mass. 01835-8099, USA
Amersham Biosciences UK Ltd, Pollards Wood, Chalfont St Giles, Buckinghamshire HP8 4SP, United Kingdom
Apin Chemicals Ltd., 82 C Milton Park, Abingdon, Oxon OX14 4RY, United Kingdom
Apollo Scientific Ltd., Unit 1A, Bingswood Industrial Estate, Whaley Bridge, Derbyshire SK23 7LY, United Kingdom
Arch Corporation, 100 Jersey Avenue, Building D, New Brunswick, N.J. 08901, USA
Array Biopharma Inc., 1885 33rd Street, Boulder, Colo. 80301, USA
Asinex-Reag.
AstaTech, Inc., 8301 Torresdale Ave., 19C, Philadelphia, Pa. 19136, USA
Austin Chemical Company, Inc., 1565 Barclay Blvd., Buffalo Grove, Ill. 60089, USA
Avocado Research, Shore Road, Port of Heysham Industrial Park, Heysham, Lancashire LA3 2XY, United Kingdom
Bayer A G, Business Group Basic and Fine Chemicals, D-51368 Leverkusen, Germany
Berk Univar plc, Berk House, P.O. Box 56, Basing View, Basingstoke, Hants RG21 2E6, United Kingdom
Bionet Research Ltd; Highfield Industrial Estate, Camelford, Cornwall PL32 9QZ UK
Butt Park Ltd., Braysdown Works, Peasedown St. John, Bath BA2 8LL, United Kingdom
Chemical Building Blocks (catalogue name), Ambinter, 46 quai Louis Bleriot, Paris, F-75016, France
ChemBridge Europe, 4 Clark's Hill Rise, Hampton Wood, Evesham, Worcestershire WR11 16FW, United Kingdom
ChemService Inc., P.O. Box 3108, West Chester, Pa. 19381, USA
CiventiChem, PO Box 12041, Research Triangle Park, N.C. 27709, USA
Combi-Blocks Inc., 7949 Silverton Avenue, Suite 915, San Diego, Calif. 92126, USA
Dynamit Nobel GmbH, Germany; also available from: Saville Whittle Ltd (UK agents of Dynamit Nobel), Vickers Street, Manchester M40 8EF, United Kingdom
E. Merck, Germany; or E. Merck (Merck Ltd), Hunter Boulevard, Magna Park, Lutterworth, Leicestershire LE17 4XN, United Kingdom
Esprit Chemical Company, Esprit Plaza, 7680 Matoaka Road, Sarasota, Fla. 34243, USA
Exploratory Library (catalogue name), Ambinter, 46 quai Louis Bleriot, Paris, F-75016, France
Fluka Chemie AG, Industriestrasse 25, P.O. Box 260, CH-9471 Buchs, Switzerland
Fluorochem Ltd., Wesley Street, Old Glossop, Derbyshire SK13 7RY, United Kingdom
Heterocyclic Compounds Catalog (Florida Center for Heterocyclic Compounds, University of Florida, PO Box 117200, Gainsville, Fla. 32611-7200 USA
ICN Biomedicals, Inc., 3300 Hyland Avenue, Costa Mesa, Calif. 92626, USA
Interchim Intermediates (catalogue name), Interchim, 213 Avenue Kennedy, BP 1140, Montlucon, Cedex, 03103, France
Key Organics Ltd., 3, Highfield Industrial Estate, Camelford, Cornwall PL32 9QZ, United Kingdom
Lancaster Synthesis Ltd., Newgate, White Lund, Morecambe, Lancashire LA3 3DY, United Kingdom
Manchester Organics Ltd., Unit 2, Ashville Industrial Estate, Sutton Weaver, Runcorn, Cheshire WA7 3 PF, United Kingdom
Matrix Scientific, P.O. Box 25067, Columbia, S.C. 29224-5067, USA
Maybridge Chemical Company Ltd., Trevillett, Tintagel, Cornwall PL34 0HW, United Kingdom
Maybridge Combichem (catalogue name), Maybridge Chemical Company Ltd., Trevillett, Tintagel, Cornwall PL34 0HW, United Kingdom
Maybridge Reactive Intermediates (catalogue name), Maybridge Chemical Company Ltd., Trevillett, Tintagel, Cornwall PL34 0HW, United Kingdom
MicroChemistry Building Blocks (catalogue name), MicroChemistry-RadaPharma, Shosse Entusiastov 56, Moscow, 111123, Russia
Miteni S.p.A., Via Mecenate 90, Milano, 20138, Italy
Molecular Devices Corporation, Sunnydale, Calif., USA
N.D. Zelinsky Institute, Organic Chemistry, Leninsky prospect 47, 117913 Moscow B-334, Russia
Oakwood Products Inc., 1741, Old Dunbar Road, West Columbia, S.C., 29172, USA
OmegaChem Inc., 8800, Boulevard de la Rive Sud, Levis, PQ, G6V 9H1, Canada
Optimer Building Block (catalogue name), Array BioPharma, 3200 Walnut Street, Boulder,

Colo. 80301, USA

Peakdale Molecular Ltd., Peakdale Science Park, Sheffield Road, Chapel-en-1e-Frith, High Peak

SK23 0PG, United Kingdom

Pfaltz & Bauer, Inc., 172 East Aurora Street, Waterbury, Conn. 06708, USA
Qualigens Fine Chemicals
Rare Chemicals (catalogue name), Rare Chemicals GmbH, Schulstrasse 6, 24214 Gettorf, Germany
Rieke
SALOR (catalogue name) (Sigma Aldrich Library of Rare Chemicals), Aldrich Chemical Company Inc, 1001 West Saint Paul Avenue, Milwaukee, Wis. 53233, USA
Sigma (catalogue name), Sigma-Aldrich Corp., P.O. Box 14508, St. Louis, Mo. 63178-9916, USA; see “Aldrich” above for other non-US addresses and other contact details
SIGMA-RBI, One Strathmore Road, Natick, Mass. 01760-1312, USA
Spectrochem
Synchem OHG Heinrich-Plett-Strasse 40, Kassel, D-34132, Germany
Syngene International Pvt Ltd, Hebbagodi, Hosur Road, Bangalore, India.
TCI America, 9211 North Harborgate Street, Portland, Oreg. 97203, USA
TimTec Building Blocks A or B, TimTec, Inc., P O Box 8941, Newark, Del. 19714-8941, USA
TimTec Overseas Stock, TimTec Inc., 100 Interchange Blvd. Newark, Del. 19711, USA
TimTec Stock Library, TimTec, Inc., P O Box 8941, Newark, Del. 19714-8941, USA
Trans World Chemicals, Inc., 14674 Southlawn Lane, Rockville, Md. 20850, USA
Tyger
Ubichem PLC, Mayflower Close, Chandlers Ford Industrial Estate, Eastleigh, Hampshire SO53 4AR, United Kingdom
Ultrafine (UFC Ltd.), Synergy House, Guildhall Close, Manchester Science Park, Manchester M15 6SY, United Kingdom

TABLE 1

Intermediates

Intermediate
No.	Name

1	1-ethyl-1H-pyrazol-5-amine
2	diethyl (1-chloropropylidene)propanedioate
2A	diethyl (1-chloro-1-propen-1-yl)propanedioate and/or
	diethyl (1-chloropropylidene)propanedioate
2B	diethyl {1-[(1-ethyl-1H-pyrazol-5-yl)amino]propylidene}propanedioate
2C	ethyl 1,6-diethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
3	ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
4	ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-
	b]pyridine-5-carboxylate
5	[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-
	b]pyridin-5-yl]methanol
6	5-(azidomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-
	pyrazolo[3,4-b]pyridin-4-amine
7	5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-
	pyrazolo[3,4-b]pyridin-4-amine
7A	5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-
	pyrazolo[3,4-b]pyridin-4-amine monohydrochloride
10	8-bromooctanoyl chloride
12	8-bromo-N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-
	pyrazolo[3,4-b]pyridin-5-yl]methyl}octanamide
13	ethyl 4-[(1-{[(1,1-dimethylethyl)oxy]carbonyl}-4-piperidinyl)amino]-1,6-
	diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
14	1,1-dimethylethyl 4-{[1,6-diethyl-5-(hydroxymethyl)-1H-pyrazolo[3,4-
	b]pyridin-4-yl]amino}-1-piperidinecarboxylate
15	1,1-dimethylethyl 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-
	b]pyridin-4-yl]amino}-1-piperidinecarboxylate
16	4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-
	1-piperidinecarboxamide
17	4-{[5-(aminomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-
	1-piperidinecarboxamide
18	4-[(5-{[(8-bromooctanoyl)amino]methyl}-1,6-diethyl-1H-pyrazolo[3,4-
	b]pyridin-4-yl)amino]-1-piperidinecarboxamide
29	diethyl (1-chloroethylidene)propanedioate
30	ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-
	carboxylate
31	ethyl 1-ethyl-6-methyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-
	pyrazolo[3,4-b]pyridine-5-carboxylate
32	[1-ethyl-6-methyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-
	b]pyridin-5-yl]methanol
33	5-(azidomethyl)-1-ethyl-6-methyl-N-(tetrahydro-2H-pyran-4-yl)-1H-
	pyrazolo[3,4-b]pyridin-4-amine
34	5-(aminomethyl)-1-ethyl-6-methyl-N-(tetrahydro-2H-pyran-4-yl)-1H-
	pyrazolo[3,4-b]pyridin-4-amine
48	5-(aminomethyl)-1-ethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-
	b]pyridin-4-amine hydrochloride

Intermediate 1: 1-Ethyl-1H-pyrazol-5-amine

Acrylonitrile (536 g, 10.11 moles, commercially available e.g. from E. Merck) is added dropwise to hydrazine hydrate (511 g, 10.22 moles, commercially available e.g. from Qualigens Fine Chem.) maintaining the reaction temperature between 30 and 35° C. (a little exothermicity can be observed). After completion of the addition the reaction mixture is stirred at the same temperature for an additional hour. Water from the mixture is removed at 45-50° C. under reduced pressure to give the Michael addition product (2-cyanoethylhydrazine, e.g. this can be a pale yellow oil), which can be used in the next step without further purification.
A solution of acetaldehyde (561 ml, 9.99 moles, commercially available e.g. from Sigma-Aldrich) in ethanol (1008 ml) is added dropwise to a stirred solution of 2-cyanoethylhydrazine (835 g, 9.82 moles) in ethanol (700 ml) at such a rate that the temperature does not rise above 35° C. The batch is heated under reflux for 1 hour and ethanol is removed under reduced pressure to afford the Schiff's base (e.g. this can be a pale yellow oil), which can be directly used in the subsequent step.
The Schiff's base is added to a stirred mixture of sodium-tert-butoxide (908 g, 9.46 mol) in t-butanol and the reaction mixture is heated under reflux for 12 hours. The cooled reaction mixture is then poured into water (23 L), stirred for 0.5 hours and extracted with diethyl ether (1×10 L and 3×6 L). The combined organic layer is dried (Na₂SO₄) and the solution is evaporated to dryness. The residue is dissolved in dichloromethane (1.5 L) to remove impurities and the solvent is evaporated to dryness to give the title compound (e.g. this can be a red oil), which can optionally be used without further purification.

Intermediate 2: Diethyl (1-chloropropylidene)propanedioate

To a mixture of diethyl malonate (704 g, e.g. available from Spectrochem) and acetonitrile (3.8 L) was added anhydrous magnesium chloride immediately (419 g, e.g. available from Lancaster). Triethylamine (1222 ml) was added dropwise, maintaining the temperature at 5-10° C., followed by the dropwise addition of propionyl chloride (406 g), maintaining the temperature at or below 30° C. The reaction mixture was kept at 10-15° C. for 1 hour, and then the mixture was kept overnight at room temperature. The next day, aqueous hydrochloric acid (1 M) was added to the reaction mixture until the pH of the mixture was about 2.0 (approx. 4.8 L was required). The mixture was extracted with diethyl ether (3×800 ml). The combined ethereal extracts were washed with aqueous hydrochloric acid (1M, 2×1000 ml), followed by water (2×1000 mL) and finally with brine (2×1000 mL). Evaporation of the solvent from the ethereal extracts under reduced pressure afforded diethyl propanoylpropanedioate (845 g) as a yellow oil.
Tri-n-butylamine (316 ml) was added dropwise to a mixture of the above keto-diester derivative (300 g) in phosphorus oxychloride (POCl₃, 3.1 L) at room temperature. The reaction mixture was then heated under reflux for 7 hours. After cooling to room temperature, excess phosphorus oxychloride was removed by distillation under reduced pressure. The reaction mixture was then cooled to room temperature and extracted with a 1:2 mixture of hexane and diethyl ether (3×1.2 L). The combined organic extracts were washed with aqueous hydrochloric acid (1 M, 1×1 L), aqueous sodium hydroxide solution (0.1 M, 2×500 ml), brine (2×500 ml) and dried. Evaporation of the solvent under reduced pressure afforded the title compound (245 g) as a red oil which was not further purified.

Intermediate 2A: Diethyl (1-chloro-1-propen-1-yl)propanedioate and/or diethyl (1-chloropropylidene)propanedioate

There are two stages to this reaction, as follows:

“Stage 1a”: Preparation of Diethyl Propanoylpropanedioate

The following reaction was conducted under a nitrogen atmosphere. The volumes and equivalents stated are relative to the diethyl malonate.
Diethyl malonate (25 g, 23.7 ml, 0.156 mol, 1.0 equivalent) was charged to a clean dry reaction vessel followed by acetonitrile (125 ml, 5 volumes). The solution was cooled to 0-5° C. Anhydrous magnesium chloride (MgCl₂, 15.04 g, 0.158 mol, 1.01 equivalents) was added in 6 portions over 15 minutes, ensuring the internal temperature (T_int) was less than 20° C. (the maximum internal temperature during the addition (T_max) actually was 15° C.). The slurry was cooled to 0-5° C. and triethylamine (43.3 ml, 31.59 g, 0.312 mol, 2.0 equivalents) was slowly charged to the vessel from a dropping funnel over 27 minutes, maintaining T_int<20° C. (T_maxactually was 9° C.). A solution of propionyl chloride (13.7 ml, 14.59 g, 0.158 mol, 1.01 equivalents) in acetonitrile (10 ml) was added slowly via a dropping funnel to the reaction mixture over 20 minutes, maintaining T_int<20° C. (T_maxactually was 15° C.). The reaction mixture was stirred at 10-15° C. for about 54-60 minutes, and then allowed to warm to 20-25° C. (cooling removed) and stirred at 20-25° C. for about 2 hours. The reaction mixture was cooled. Toluene (50 ml) was then added in one portion, followed by 1 M aqueous hydrochloric acid (115 ml) which was added over 9 minutes via a dropping funnel (during which time an ice bath was used, with T_maxbeing 19° C.). The reaction mixture was stirred for 35 minutes, and then transferred to a separating funnel after standing for 5 minutes. Some grey solids were observed in the organic layer. The pH of the aqueous layer was about 6. Aqueous hydrochloric acid (2 M, 23 ml) was added, after which the pH of the aqueous layer was about 0-1. The two layers were then separated and the aqueous layer was back-extracted with toluene (50 ml). The back extraction was repeated. The combined organic layers were then washed with 1 M citric acid (50 ml) (whereupon the organic layer became milky), followed by 2 M aqueous hydrochloric acid (40 ml), water (40 ml), 15 wt % brine solution (50 ml) and a further 15 wt % brine solution (50 ml). The resulting slightly translucent opalescent organic layer was concentrated using a rotary evaporator to a volume of 100 ml. The yield of the reaction using a 1H NMR assay was calculated as about 32.3 g, about 0.149 moles, about 95.8% theory yield. This mixture of diethyl propanoylpropanedioate in toluene was used directly in the Stage 1b reaction below.

“Stage 1b”: Preparation of diethyl (1-chloro-1-propen-1-yl)propanedioate

The following reaction was conducted under a nitrogen atmosphere.
Triethylamine (19.17 ml, 16.59 g, 0.1639 moles, 1.1 equivalents) was added in four portions to a reaction vessel containing the 100 ml toluene solution of diethyl propanoylpropanedioate [calculated by 1H NMR to contain about 32.3 g (about 0.149 moles, 1 equivalent) of diethyl propanoylpropanedioate] which was prepared in the Intermediate 2 (Stage 1a) process disclosed hereinabove. The reaction mixture was heated to 70° C. A mixture of phosphorus oxychloride (POCl₃, 20.83 ml, 34.27 g, 0.2235 moles, 1.5 equivalents) in toluene (60 ml) was slowly added to the rapidly-stirred reaction vessel, maintaining T_int<85° C. The contents were then stirred at 85° C. for about 21 hours. The reaction mixture was then cooled using an ice bath to approximately 5° C., and water (90 ml) was added over 1 hour (with the first 70 ml added very slowly), with the maximum internal temperature during the addition (T_max) being 18° C. The biphase was vigorously stirred at 5-10° C. for 15 minutes, and then the two layers were allowed to separate. The aqueous layer was separated and discarded. To the organic layer was added water (90 ml) in one portion and the mixture stirred for 15 mins and then allowed to separate. Due to slow separation and/or partial emulsification at the interface, most of the aqueous layer was removed, and then brine (20 ml) was added in an attempt to aid the separation. After 20 mins, the aqueous layer, including some emulsion and solid/scum from the interface, was separated and discarded. 1M Sodium bicarbonate solution (90 ml) was added to the organic layer and the biphase was stirred for 30 minutes. After the two layers were separated, extra toluene (60 ml) was added to the organic layer. The organic layer was concentrated to 100 ml volume in vacuo. The yield of the reaction using a 1H NMR assay was calculated as about 28.2 g, about 0.120 moles, about 80.7% theory yield.

- Note: 1H NMR analysis, of a mini-worked-up sample of the crude reaction mixture and/or of the final toluene product solution, appears to suggest that the major product of the reaction is the unconjugated vinyl chloride, diethyl (1-chloro-1-propen-1-yl)propanedioate, as illustrated above.

Intermediate 2B: Diethyl {1-[(1-ethyl-1H-pyrazol-5-yl)amino]propylidene}propanedioate (“Stage 1c” Preparation)

The following reaction was conducted under a nitrogen atmosphere.
5-Amino-1-ethylpyrazole (5.85 g, 0.0526 moles, 1.06 equivalents) was added in one portion to 31.35 g of a solution at room temperature, wherein the solution is of diethyl (1-chloro-1-propen-1-yl)propanedioate and/or diethyl (1-chloropropylidene)propanedioate (about 11.65 g, 0.0496 moles, 1.0 equivalent) in toluene (about 19.70 g). Triethylamine (14 ml, 10.05 g, 0.0993 moles, 2.0 equivalents) was added slowly to the reaction mixture ensuring T_int<30° C. by use of an ice bath. The reaction mixture was then heated at 90° C. for approximately 15.5 hours and then was allowed to cool to room temperature. The reaction mixture was filtered, the filter cake was washed with toluene (23 ml), and then the filter cake was pulled dry. Toluene (12 ml) was added to the filtrate, and the solution was concentrated in vacuo to about 55 ml volume. Toluene (12 ml) was added to the solution which was then concentrated down to about 55 ml, and this toluene (12 ml) addition and evaporation was repeated. The toluene solution (about 55 ml) was washed with 2M aqueous sodium hydroxide solution (55 ml), and the two layers were separated. The organic layer was concentrated to dryness to yield diethyl {1-[(1-ethyl-1H-pyrazol-5-yl)amino]propylidene}propanedioate as a brown liquid (11.11 g, about 72% theory yield). HPLC (5 min generic solvent gradient): T_RETabout 3.05. Mass Spectrum: Found: MH⁺310.1, (M-H)⁻308.1.

Intermediate 2C: Ethyl 1,6-diethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (“Stage 1d” Preparation)

The following reaction was conducted under a nitrogen atmosphere.
Diethyl {1-[(1-ethyl-1H-pyrazol-5-yl)amino]propylidene}propanedioate (1.00 g, 3.23 mmol, e.g. which can be as prepared in Intermediate 2B) was dissolved in toluene (8 ml). To the resulting dark orange solution, 1,8-diazabicyclo[5.4.0]undec-7-ene (“DBU”, 0.97 ml, 0.98 g, 6.46 mmol, 2.0 equivalents) was added, and the reaction mixture was heated at reflux for 17 hours. Further toluene (8 ml) was added to the reaction mixture, after a reduction in volume after heating had been noted. The reaction mixture was allowed to cool, and was washed with water (8 ml). The two layers were separated, and the organic layer was discarded after HPLC analysis suggested that the majority of the product was in the aqueous layer. The aqueous layer, whose pH was 12, was acidified to pH 1 using concentrated aqueous hydrochloric acid (0.6 ml), whereupon gas was seen to evolve and solid precipitated spontaneously from solution. This solid was filtered and washed with water. The resulting beige solid (0.55 g) was dried in a vacuum oven at 60° C. overnight. The title compound was obtained as a beige solid (0.46 g, about 54% theory yield). HPLC (5 min generic solvent gradient): T_RETabout 2.33. Mass Spectrum: Found: MH⁺264.1, (M-H)⁻262.1.

Intermediate 3: Ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Triethylamine (230 ml) was added dropwise to a mixture of diethyl (1-chloropropylidene)propanedioate (208 g, e.g. which can optionally be as prepared in Intermediate 2) and 1-ethyl-1H-pyrazol-5-amine (101 g, e.g. which can optionally be as prepared in Intermediate 1) in toluene (2.65 L). The mixture was heated under reflux for 16 hours. The reaction mixture was then cooled to room temperature, and filtered through a sintered glass funnel to remove the solid present. The filtrate was evaporated under reduced pressure. The residue was then treated with phosphorus oxychloride (POCl₃, 2.65 L) and the mixture was heated under reflux for 16 hours. Excess phosphorus oxychloride was removed by distillation (e.g. under reduced pressure). The reaction mixture was then cooled and poured onto a mixture of saturated aqueous sodium hydrogen carbonate solution (4 L) and ethyl acetate (1.5 L), maintaining the temperature at 5° C. The organic layer was separated and the aqueous layer further extracted with ethyl acetate (2×1 L). The combined organic extracts were washed with aqueous sodium hydrogen carbonate solution (1×2 L, e.g. optionally a saturated solution thereof and were dried (Na₂SO₄). Evaporation of solvent under reduced pressure afforded the crude product (202 g). The crude product was purified by chromatography (silica gel 60-120 mesh, 3.5 kg) eluting with 3% ethyl acetate in hexane. Fractions containing the product were pooled and evaporated to give the title compound (133 g) (which in one embodiment can be e.g. a pale yellow thick liquid or oil which may solidify on standing). 1H NMR (200 MHz, chloroform-d) δ (delta) ppm 1.37 (3H, t, J=7.1 Hz), 1.45 (3H, t, J=7.1 Hz), 1.57 (3H, t, J=7.2 Hz), 2.91 (2H, q, J=7.1 Hz), 4.48 (2H, q, J=7.2 Hz), 4.57 (2H, q, J=7.1 Hz) 8.05 (1H, s).

Intermediate 3 (Alternative Preparation): Ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (“Stage 2a” Preparation)

The following reaction was conducted under a nitrogen atmosphere.
Ethyl 1,6-diethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (0.10 g, 0.38 mmol, 1 equivalent, e.g. which can be as prepared in Intermediate 2C) was dissolved in dichloromethane (1.5 ml). Oxalyl chloride (0.07 ml, 0.10 g, 0.76 mmol, 2.0 equivalents) was added in one portion to the stirred solution. The reaction mixture, a solution, was stirred at room temperature for 2 hours, then was heated to 39° C. and stirred for 22.5 hours at this temperature, and then allowed to cool. The reaction mixture was diluted with toluene and then the solvent was removed in vacuo to give a brown oil which solidified on standing at room temperature to yield the title compound as a brown solid (0.086 g, about 80% theory yield). HPLC (5 min generic solvent gradient): T_RETabout 3.43. Mass Spectrum: Found: MH⁺282.1.

Intermediate 4: Ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

To a solution of ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (36.0 g, 127.8 mmol, 1 equivalent, e.g. which can optionally be as prepared in Intermediate 3) in N-methyl-2-pyrrolidinone (NMP, 300 ml) was added N,N-diisopropylethylamine (44.51 ml, 33.03 g, 255.6 mmol, 2.0 equivalents), resulting in a colour change from yellow to orange. Tetrahydro-2H-pyran-4-amine (15.51 g, 153.3 mmol, 1.2 equivalents, commercially available e.g. from Peakdale or Combi-Blocks) was added, and the reaction mixture was heated at 115° C. with stirring overnight (for about 21.5 hours). The reaction mixture was cooled to room temperature and poured into water (1200 ml), forming an oily orange mixture. This mixture was extracted with ethyl acetate (4×250 ml). The organic extracts were combined, were washed with water (50 ml) and 5% aqueous lithium chloride solution (50 ml), and were dried (brine/MgSO₄), filtered and evaporated to give an orange oil (46.25 g) as the residue. This residue was purified by silica gel (1 kg) chromatography, eluting with 2:1 cyclohexane:ethyl acetate (6000 ml) followed by 1:1 cyclohexane:ethyl acetate (3000 ml). The fractions containing the product only (whose R_Fis about 0.40 by TLC in 2:1 cyclohexane:ethyl acetate) were pooled and evaporated to give the title compound as a mobile yellow oil (33.90 g, ca. 76.6% yield) which solidified to a yellow solid on standing. LCMS m/z 347 [MH⁺]; T_RET=3.01 min.

Intermediate 4 (Alternative Preparation): Ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (“Stage 2b” Preparation)

The following reaction was conducted under a nitrogen atmosphere.
Ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate [0.75 g, 2.66 mmol, 1.0 equivalent] was dissolved in 1-methyl-2-pyrrolidinone (NMP, 4 ml). 4-Amino-tetrahydro-2H-pyran acetate (0.51 g, 3.19 mmol, 1.2 equivalents) was added in one portion to the stirred solution at room temperature. The reaction mixture was stirred for 15 minutes and then potassium carbonate (1.10 g, 7.99 mmol, 3.0 equivalents) was added in one portion. The reaction mixture was heated to and at 100° C. for 16 hours, and then cooled before partitioning between ethyl acetate (25 ml) and water (25 ml) whereupon an emulsion formed. To this biphase mixture/emulsion was added brine, followed by water (20 ml) and then ethyl acetate (20 ml), to aid separation. The two layers were separated and the aqueous layer was washed with ethyl acetate (20 ml). The organic layers were combined and washed with 1M aqueous hydrochloric acid (3×25 ml). To the combined aqueous layers was added ethyl acetate (25 ml); the resulting biphasic mixture was stirred vigorously, and then 10M aqueous sodium hydroxide solution (14.5 ml) was added to this stirred mixture until the pH of the now-warm mixture was measured to be about 13. The mixture was allowed to separate. The separated aqueous layer was washed with ethyl acetate (20 ml). The combined organic layers were washed with water (20 ml) followed by brine (20 ml). The organic layer was concentrated to dryness to give an orange oil which visually appeared to contain sodium chloride or similar crystals. This oil was dissolved in ethyl acetate and washed with a minimal amount of water; separation was poor. The organic layer was separated and concentrated to dryness, to give the title compound as an orange oil (still containing some crystals) which solidified after standing overnight at room temperature (0.58 g, about 63% yield).

Intermediate 5: [1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

A solution of ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (17.94 g, 51.85 mmol, e.g. which can optionally be as prepared in Intermediate 4) in dichloromethane (150 ml) was cooled to 0° C. under an atmosphere of nitrogen, and was treated with di-iso-butylaluminum hydride (100 ml of a 1.5 M solution in toluene, 150 mmol) added dropwise over 30 minutes, keeping the temperature steady at 0° C. The reaction was stirred at 0° C. for a further 30 minutes after completion of the addition. The reaction was quenched by the dropwise addition of saturated aqueous potassium sodium tartrate solution (120 ml), keeping the temperature below 5° C. The resulting mixture was diluted with ethyl acetate (300 ml) and the whole filtered through a pad of Celite, to form two layers. During this filtration the sinter funnel imploded. Material spilt on the fumehood floor was soaked up and recovered as much as possible. The organic layer was separated and dried (MgSO₄), the drying agent was filtered off, and the filtrate evaporated to give a first batch of product. The aqueous layer and the celite were extracted with a larger amount of ethyl acetate to give a second batch of product after evaporation. The two batches of product were combined to give the title compound (14 g) as an off-white waxy solid.

Intermediate 5 (Alternative Preparation No. 1): [1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

To a mixture of ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (60.43 g, 174 mmol, 1 equivalent, e.g. which can optionally be as prepared in Intermediate 4) in dry tetrahydrofuran (300 ml) was added dry methanol (28.3 ml, 22.3 g, 698 mmol, 4 equivalents), followed by slow addition of lithium borohydride (LiBH₄, 2 M solution in tetrahydrofuran, 262 ml, 523 mmol, 3 equivalents) over 30 minutes. The mixture was heated as the lithium borohydride was added, reaching reflux after about 20 minutes. Further aliquots of methanol (14.1 ml, 2 equivalents, each time) were added after 1 hour and again after 1.5 hours, and the heating was continued for a further 30 minutes (for 2 hours total). The reaction mixture was cooled (ice/water bath) and was carefully treated with methanol (100 ml, non-dried) followed by cautious addition of water (200 ml) which resulted in cloudiness and then a precipitate. Addition of more water (800 ml) produced a more homogenous suspension which was stirred for 1 hour and which was then extracted with dichloromethane (about 1.5 L total volume). The organic extracts were combined, were washed with water and then brine, and were dried and evaporated to give the title compound as a white solid (49.84 g). LCMS m/z 305 [MH⁺]; T_RET=1.79 and 1.83 min (double peak).

Intermediate 5 (Alternative Preparation No. 2, Plant Method): [1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

Summary of Plant Method

All weights, volumes (vol., vols) and equivalents are relative to the ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate.
The reaction is conducted under a nitrogen atmosphere, in a plant, and the organic reaction solvents are usually dry or moderately dry.
To a stirred solution of lithium borohydride (LiBH₄, 3 eq, 4.34 vol, 2M solution in tetrahydrofuran (THF)) and dry toluene (4 vols) at 64-68° C., is added a solution of ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1 wt, e.g. which can optionally be as prepared in Intermediate 4) in dry THF (1 vol.) and dry methanol (9 eq, 1.05 vol.) over at least 2.5 hours. The reaction is monitored by HPLC and is typically complete about 60 minutes (50-70 mins) after the end of the addition. The reaction mixture is then cooled down to 20±3° C., and water (3 vol.) is added dropwise over at least 30 mins followed by aqueous sodium hydroxide solution (10.8M, about 32% w/w, 6.0 vols, 8.1 wt) (dropwise over about 30-40 mins), ensuring the temperature remains below 40° C. The temperature of the reaction is then adjusted to 37±3° C. and stirred vigorously for at least 90 minutes. The organic layer and aqueous layer are separated and the aqueous layer is treated with sulphuric acid (11 vol., 13.2 wt) to remove any remaining lithium borohydride. Water (2.5 vols) is added to the organic layer over at least 30 mins followed by aqueous sodium hydroxide solution (10.8M, about 32% w/w, 2 vols, 2.7 wt) over about 30-40 mins, and the biphase is stirred vigorously at 37±3° C. for at least 30 minutes. The organic layer is again separated and the organic solution is concentrated in vacuo to 3 vols, which precipitates the product, usually as yellow solid. Toluene (3 vol.) is then added and the slurry is reconcentrated in vacuo to 3 vol. The suspension is then cooled to 10±3° C. and aged for at least 30 min. The solid is then filtered and washed with toluene (3 vol.). The product [1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol is then dried in vacuo at about 45° C. to constant temperature.

Step-Wise Methodology Used in One Pilot Plant Batch

All weights, volumes (vol., vols) and equivalents are relative to the ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate.
The reaction was conducted under a nitrogen atmosphere, in a pilot plant.
1. Making up solution of ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate:
Dry THF (1 vol., 11 litres) was charged to a glass lined reactor followed by dry methanol (1.0 vol., 11 litres), the mixture was stirred at 20±5° C. for about 10 min at 75 rev./min, and ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1 wt, 11.0 kg) was added. The walls of the charge hole (for the solid ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate) were washed clean with dry methanol (0.05 vol., 0.55 litres) which went into the reactor. The contents of the glass lined reactor were stirred at 20±5° C. for about 1 hr 11 minutes at 75 rev./min.
2. Dry toluene (4 vol., 44 litres) was charged to a separate glass lined reactor and the contents were stirred.
3. A 2M solution of lithium borohydride in THF (3.89 wt, 42.8 kg) was charged to the stirred toluene-containing reactor over about 1 hour from a cylinder using a pyrophoric dispensing manifold. The contents of the reactor were heated to 66±3° C. (target range 64-68° C.) over about 50 mins.
4. The solution made up in step 1 was then charged to the stirred toluene and LiBH₄solution via a peristaltic pump over 2 hrs 34 minutes, maintaining the reactor contents at a temperature of 66±3° C. (target range 64-68° C.) whilst maintaining an even paced addition rate.
5. After the addition of the ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate, the reaction contents were stirred at 66±3° C. (target range 64-68° C.) (contents temperature) at 75 rev./min for 65 minutes, and the reaction was sampled for HPLC analysis. HPLC indicated <6% a/a (about 4.7%) of the ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate remaining, and so the reaction was considered complete.
6. Straight after the sample has been taken, the contents were cooled to 20±3° C. over about 30 mins with stirring.
7. With the stirrer speed of the reactor increased to 125 rev./min, water (3 wt, 33.00 kg, 33 litres) was added to the reaction via a peristaltic pump over 33 minutes, during which the contents temperature was kept below 40° C. (T_maxof the contents was 32° C.). During this water addition the product usually precipitates forming a thick suspension.
8. After the water addition was complete the reactor contents were cooled to 20±5° C.
9. Aqueous sodium hydroxide solution (about 32% w/w, 8.1 wt, 89.10 kg) was added to the reactor via a peristaltic pump over 35 minutes.
10. After the addition of the sodium hydroxide solution, the contents of the reactor were stirred at 37±3° C. for 90 minutes.
11. The agitator was stopped and the layers were allowed to separate for at least 15 min.
12. The lower aqueous layer was separated and transferred to another vessel.
13. The upper organic layer was cooled to 20±3° C., and was held for about 9.5 hours. 13A. With the stirrer speed of the reactor increased to 125 rev./min, water (2.5 wt, 27.50 kg) was added to the organic layer via a peristaltic pump over 30 minutes, during which time the contents temperature was kept below 40° C.
14. The reactor contents were cooled to 20±5° C., and aqueous sodium hydroxide solution (about 32% ww, 2.7 wt, 29.70 kg) was added via a peristaltic pump over 35 minutes.
15. The contents of the reactor were stirred at 37±3° C. for 33 minutes.
16. The stirrer was stopped and the layers were allowed to separate for 15 minutes.
17. The lower aqueous layer was separated and transferred to another vessel.
18. The remaining reactor contents (organic layer) was stirred and cooled to 5±3° C. and then medium vacuum was applied (about −0.8 to −0.85 barg vacuum) to degas the reactor contents (to remove the hydrogen formed in the reaction).
19. The reactor contents were adjusted to 5° C. with stirring, and the reactor contents were heated under a vacuum of about −0.83 barg. Initially the reactor contents were heated to about 26° C. and eventually to about 45° C., to remove solvent by vacuum distillation until the batch was concentrated to about 33 litres (about 3 vols). The distillation is complete after 4.5 hours of heating, leaving a slurry in the reactor.
20. The vacuum was released and toluene (3 vols, 33 litres) was charged to the reactor.
21. The reactor contents were adjusted to 5° C. with stirring.
22. The reactor contents were heated, under a vacuum ranging from about −0.84 barg to about −0.91 barg. The reactor contents were heated to about 40° C. (at about −0.84 barg) and then to a maximum of 46° C. (at about −0.88 barg) and then to about 40° C. (at about −0.91 barg), to remove solvent by vacuum distillation until the batch was concentrated to about 33 litres (about 3 vols). The distillation was complete after about 4 hours 18 minutes of heating.
23. The vacuum was released and the contents were cooled to 10±3° C. and stirred at this temperature for about 6.25 hours at 75 rev./min.
24. The resulting slurry was then transferred to a 20 micron filter cloth, and filtered under nitrogen pressure (0.5-1 barg).
25. The filter cake was washed with toluene (3 vol., 33 litres) under nitrogen pressure (0.5-1 barg), and then solvent was blown from the filter cake using nitrogen pressure over 11 minutes.
26. The damp filter cake was transferred to polyethene lined trays, covered with muslin bags, placed in a vacuum tray dryer, and was dried by heating to 47±3° C. under vacuum (using a 5 L/min nitrogen bleed to the dryer, to minimise build-up of condensed solvents in the oven), until a constant temperature of the solid was measured for at least 4 hours. The batch was cooled to below 30° C.
27. The product [1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol was obtained as a solid (8.55 kg, 88.5% theory yield).

- Note: The remaining additional steps, below, concern the acidic quenching of the aqueous layers and mother liquors which is done for safety reasons to remove any borohydride residues left in these solutions on plant. These stages are waste management steps, separate to the core production of product, and so are not essential and may or may not be performed as is desired.
  28. The aqueous layers from step 12 & 17 are stirred and cooled to 5±3° C.
  29. 5M sulphuric acid (13.2 wt, 145.2 kg) is charged to the aqueous layers via peristaltic pump over 3 hrs 52 minutes maintaining a contents temperature below 40° C.
  30. Post the acid addition, the contents are stirred at 5±5° C. for 2 hrs 18 minutes. The pH is checked, if the pH <3 the quench is considered complete.
  31. The reactor is degassed using vacuum and purging with nitrogen before the aqueous solution is discharged and labelled as waste.
  32. The mother liquors produced during the filtration steps (24 & 25) are transferred to a reactor, stirred and cooled to 5±3° C.
  33. Water (5 litres) is charged to the liquors.
  34. 5M sulphuric acid (1 kg) is charged to the aqueous layers via peristaltic pump over 1 hr maintaining a contents temperature below 40° C.
  35. After the acid addition, the contents are stirred at 5±5° C. for 2 hrs 18 minutes. The pH is checked; if the pH <3 the quench is considered complete.
  36. The reactor is degassed using vacuum and purging with nitrogen before the biphasic solution is discharged and labelled as waste.

Intermediate 6: 5-(Azidomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

Thionyl chloride (SOCl₂, 50.37 ml, 82.11 g, 69 mmol) was added dropwise over 15 minutes to a suspension of [1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol (13.98 g, 46 mmol, e.g. which can optionally be as described in Intermediate 5) in toluene (140 ml) at room temperature. The mixture was then heated at reflux at about 85° C. for 4 hours, was allowed to cool, and then was evaporated to dryness and azeotroped with three further portions of toluene. The residue obtained was dissolved in dry dimethylsulfoxide (100 ml) and treated with sodium azide (4.49 g, 69 mmol), and the mixture was stirred at room temperature for 18 hours. The mixture was poured into saturated aqueous sodium bicarbonate solution and was extracted with 3 portions of ethyl acetate. The combined organic extracts were washed with saturated brine and water, and were then dried (Na₂SO₄), the drying agent was filtered off, and the filtrate was evaporated to dryness. The residue obtained was purified by flash chromatography, eluting with 1:1 cyclohexane:ethyl acetate. Fractions containing the product without substantial amounts of impurities were evaporated to give the title compound (5.6 g+4.75 g=10.35 g).

Intermediate 7: 5-(Aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

A suspension of 5-(azidomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine (10.3 g, 34 mmol, e.g. which can be as prepared in Intermediate 6) in ethanol (200 ml) was added to 10% palladium on carbon (1 g) and stirred under an atmosphere of hydrogen for 3 hours at room temperature. The catalyst was removed by filtration under nitrogen and was washed well with ethanol. The filtrate was evaporated to dryness to give a dark oil. Ether was added and then evaporated to give the title compound as a foamy semi-solid (9.35 g).

Intermediate 7 (Alternative Preparation No. 1): 5-(Aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

In a hydrogenation flask, ethanol (300 ml) was added to 10% palladium on carbon (9.9 g, 0.2 wt. equivalents, 50% wet), followed by 5-(azidomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine (49.62 g, 151 mmol, 1 equivalent, e.g. which can be as prepared in Intermediate 6) in ethanol (900 ml). The mixture was hydrogenated overnight at room temperature and room pressure (using the Wright valve); during which the flask was vented and refilled once. The catalyst was removed by filtration and the filtrate was evaporated to give a grey solid. The residue was purified by column chromatography, using a relatively small amount of silica (1500 ml of 9385 silica), eluting initially with 5% methanol in dichloromethane (to elute some fast-moving impurities), followed by 10% and finally 15% methanol in dichloromethane to give the title compound as an almost white solid (41.25 g). LCMS m/z 304 [MH⁺]; T_RET=1.65 and 1.69 min (split peak). NMR (d6-DMSO) showed a trace of methanol present in the product.

Intermediate 7A: 5-(Aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine monohydrochloride (Plant Method)

Intermediate 7A Process Scheme

Intermediate 7A Process Summary

All weights and volumes are relative to [1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol starting material, unless otherwise stated.
The reactions are conducted under an atmosphere of nitrogen in plant, and the organic reaction solvents are usually dry or moderately dry.
[1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol (1 wt) (e.g. preferably substantially as prepared in Intermediate 5, alternative preparation no. 2, plant method) is suspended in dry anisole (5.97 wt, 6 vol) and treated with solid benzensulfonic acid (0.52 wt, about 1 equiv.). This suspension is aged at 20±5° C. for at least 30 minutes. Thionyl chloride (0.45 wt, about 1.15 equiv.) is added at 20±5° C. over at least 20 minutes, and stirred for between 20 and 30 minutes. The reaction is then sampled for HPLC. The resulting solution of 5-(chloromethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine benzenesulfonate is treated with dry toluene (2 vol) and then placed under medium vacuum (about −0.85 barg, e.g. about 100-150 mbar) to remove hydrogen chloride and sulfur dioxide, and then the vacuum is increased (about −0.95 barg, e.g. about 50 mbar) to azeotrope off excess thionyl chloride and toluene.
This solution/slurry of 5-(chloromethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine benzenesulfonate (ca. 7.5 vol) is added to a solution of lithium hexamethyldisilazide (LiHMDS) in tetrahydrofuran (1.3M in THF, 5.73 wt, 6.51 vol, about 2.5 equiv.) at 35±5° C. over 60-70 minutes and then stirred for a further 15 to 30 minutes.
The mixture is cooled to 10±5° C. and 5M hydrochloric acid (3.78 wt, 3.6 vol) is added. The phases are separated and the lower aqueous layer is transferred back into the vessel, and the organic phase is discarded. 2-Me-THF (2-methyl-tetrahydrofuran) (8 vol) is added and then the biphasic mixture is adjusted to pH>13 with 32% w/w aqueous sodium hydroxide solution (2.25 wt) and then warmed to 30±5° C. The layers are separated and the lower aqueous layer is back extracted with further 2-Me-THF (2 vol). The combined organic phases are washed with 15% w/w aqueous sodium chloride solution (2.2 wt).
The amount of 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine in solution is quantified via yieldaliser (uses a solution-based assay, using a comparator standard solution of known concentration), and an appropriate amount of 36% w/w aqueous hydrochloric acid (1.03 equivalents based on the calculated and/or measured amount of the product amine) is added at 55±5° C. The suspension is held for 2 hours at 55±5° C., and then cooled to 5±5° C. over 3 hours and held at 5±5° C. for at least 3 hours. The slurry is filtered and the separated solid is washed with 2-Me-THF (2×2 vol) and dried in vacuo at 60° C. to constant weight or batch temperature to give the product 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine monohydrochloride (Intermediate 7A).

Intermediate 7A: Detailed Step-Wise Methodology

All weights and volumes are relative to [1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol starting material, unless otherwise stated.
The reactions are conducted under an atmosphere of nitrogen in plant.

Chlorination Reaction

1. Anisole (5.97 wt, 71.6 kg) is charged to the reactor.
2. 1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol (1 wt, 12.0 kg) (e.g. preferably substantially as prepared in Intermediate 5, alternative preparation no. 2, plant method) is charged to the reactor.
3. Benzenesulfonic acid (0.52 wt, 6.24 kg) is charged to the reactor and the contents are stirred at 20±5° C. for 34 minutes.
4. Thionyl chloride (0.45 wt, 5.4 kg) is charged to the reactor via peristaltic pump over 28 minutes, maintaining the reactor contents at 20±5° C.
5. The reactor contents are stirred at 20±5° C. for 28 minutes and then the contents are sampled for HPLC analysis. The volume of the reaction is noted.
6. Toluene (2 vols, 24 litres) is then charged to the stirred reactor.
7. The reactor contents are placed under vacuum (ca −0.85 barg) and stirred at 20±5° C. for 1 hr 6 minutes.
8. The reactor contents are then cooled to 10° C.
9. The reactor is then subjected to full vacuum for the distillation (−0.95 to −0.97 barg).
10. The batch is then heated, with an initial internal temperature of 18° C. rising to 40° C. by the end of the distillation. The end point of the distillation is the volume noted in step 5. This is reached after 2 hrs 43 minutes of heating.
11. The vacuum is released and the contents are stirred at 20±5° C. This is the anisole slurry of 5-(chloromethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine benzenesulfonate. In this example an extra charge of 15 litres of anisole is made to this slurry.

Amination Reaction

12. To a different reactor, lithium hexamethyldisilazide (LiHMDS) solution (1.3M in THF, 5.73 wt, 68.8 kg) is charged and then the contents are stirred and heated to 35±5° C.
13. The slurry of 5-(chloromethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine benzenesulfonate (from step 11) is added to the LiHMDS solution in portions via a saunders valve over 46 minutes. The reactor contents temperature is maintained at 35±5° C.
14. In this example several rinses are conducted to clean the lines. A line wash of the Kammer valve line (which can become blocked) is conducted to clear residual solid using anisole (2 kg), and a vessel rinse using anisole (0.25 wt, 3.0 kg) is conducted to rinse further 5-(chloromethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine benzenesulfonate into the LiHMDS solution.
15. After the residual solid is rinsed in, the amination reaction is stirred at 35±5° C. for 20 minutes.
16. The amination reaction is sampled for completion by HPLC analysis.
17. The reactor contents are then stirred and cooled to 10±5° C.
18. 5M aqueous hydrochloric acid (3.78 wt, 45.4 kg) is charged to the reactor via a peristaltic pump over 52 minutes, maintaining an internal temperature of 10±5° C.
19. The resultant biphase is stirred at 10±5° C. for at least 15 minutes.
20. The stirrer is stopped and the 2 layers are allowed to separate. The lower aqueous layer is transferred to a drum and is an aqueous solution of 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine hydrochloride. The pH is checked (expect pH <5).
21. The upper organic layer is discharged as waste.
22. Further line and vessel rinses are conducted running from the ex-thionyl chloride reactor vessel through the Kammer valve to the ex-amination reactor. The rinses are THF (30 litres) and water (60 litres).
23. The aqueous solution of 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine hydrochloride (from step 20) is charged to a reactor and stirred.
24. 2-Methyl-tetrahydrofuran (2-Me-THF) (8 vol, 96 litres) is charged to the aqueous solution.
25. Aqueous sodium hydroxide solution (32% ww, 2.25 wt, 27 kg) is charged to the reactor via a peristaltic pump over 30 minutes. Reactor contents are maintained at 10±5° C.
26. The reactor contents are heated to 30±5° C. and stirred for at least 15 minutes.
27. The stirrer is stopped and the two layers are allowed to separate. The lower aqueous layer is transferred to a drum and is an aqueous solution of the product amine. Its pH is checked (expect pH >13).
28. The upper layer is also transferred to a drum and is a 2-methyl-tetrahydrofuran solution of the product amine.
29. The aqueous solution of the product amine (from step 27) is charged to the reactor and 2-methyl-tetrahydrofuran (2-Me-THF) (2 vols, 24 litres) is added to back extract the aqueous layer further. The biphase is stirred at 30±5° C. for at least 15 minutes.
30. The stirrer is stopped and the two layers are allowed to separate. The lower aqueous layer is discharged as waste, and the upper organic layer is retained in the reactor.
31. The 2-methyl-tetrahydrofuran solution of the product amine (from step 28) is charged back into the reactor and the combined organic layers are stirred.
32. 15 wt % aqueous sodium chloride solution (2.2 wt, 26.4 kg) is charged to the reactor.
33. The biphase is heated to 30±5° C. and stirred for at least 15 minutes.
34. The stirrer is stopped and the teo layers are allowed to separate. The lower aqueous layer is discharged as waste, the upper organic layer is retained in the reactor, and the volume of the solution is noted.
35. The reactor contents are sampled for HPLC analysis. An approximate yield of the product 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine is obtained from this analysis.

Formation and Isolation of Hydrochloride Salt of Amine

36. The contents of the reactor are heated to 55±5° C.
37. Concentrated aqueous hydrochloric acid (1.03 eq. relative to yield of 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine calculated in step 35, usually 2.37 kg) is added to the reactor via a peristaltic pump over 20 minutes, maintaining the reactor contents at 55±5° C.
38. The reactor contents are stirred at 55±5° C. for 2 hrs 6 minutes.
39. The reactor contents are gradually cooled to 5±5° C. over 3 hours.
40. The slurry is then stirred at 5±5° C. for at least 3 hours. In this example, the reactor contents are stirred at 5±5° C. overnight for a stir time of 19 hrs 53 minutes.
41. The slurry is transferred to a 20 micron filter cloth, is allowed to settle for 10 mins, and is filtered under nitrogen pressure (0.5 to 1 barg).
42. The filter cake is washed with 2-methyl-tetrahydrofuran (2 vols, 24 litres) under nitrogen pressure (0.5 to 1 barg).
43. The filter cake is washed with further 2-methyl-tetrahydrofuran (2 vols, 24 litres) under nitrogen pressure (0.5 to 1 barg). Further solvent is removed from the cake by blowing under nitrogen pressure over 1 hr 40 minutes.
44. The damp filter cake is transferred to plythene lined trays, covered with muslin bags, and placed in a vacuum tray dryer. The vacuum tray dryer is put under vacuum and is heated to 60±5° C. to dry the product, using a 5 L/min nitrogen bleed to the dryer (to minimise build-up of condensed solvents in the oven). The drying is considered complete when the product temperature probe reads a constant temperature for at least 4 hours.
45. The product 5-(aminomethyl)-1,6-diethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine monohydrochloride (Intermediate 7A) is collected as a solid, usually as a white solid.

Intermediate 10: 8-Bromooctanoyl Chloride

To 8-bromooctanoic acid (2.5 g, 11.2 mmol, commercially available e.g. from Aldrich) in toluene (50 ml) was added thionyl chloride (2 ml), and the mixture was stirred at room temperature overnight. The solvent was evaporated and the residue was co-evaporated with dichloromethane (2×25 ml) to give a brown oil which solidified on standing (found to be starting acid by NMR). This material was redissolved in toluene (25 ml), thionyl chloride (2 ml) was added, and the mixture was stirred at room temperature for 8 hours and then left standing overnight. The reaction mixture was evaporated to dryness and the residue was co-evaporated with dichloromethane (2×30 ml) to give the title compound as a brown oil (2.4 g), as a 3:2 mixture of product: starting acid (by NMR). 1H NMR (400 MHz, chloroform-d) δ (delta) ppm 1.37 (4H, m), 1.45 (2H, m), 1.67 (2H, m), 1.86 (2H, m), 2.90 (2H, t, J=7 Hz), 3.42 (2H, t, J=7 Hz).

Intermediate 10 (Alternative Synthesis): 8-Bromooctanoyl Chloride

8-Bromooctanoic acid (2.0 g, 8.97 mmol, commercially available e.g. from Aldrich) in thionyl chloride (2 ml) was stirred at room temperature for 1 hour and then at 100° C. for 2 hours. The thionyl chloride was removed by evaporation and the residue was co-evaporated with dichloromethane (2×30 ml) to give 8-bromooctanoyl chloride as a colourless mobile oil (2.05 g).

Intermediate 12: 8-Bromo-N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}octanamide

A solution of intermediate 7 (0.25 g) and triethylamine (0.11 ml) in chloroform (20 ml) was cooled to 0° C. and treated dropwise with intermediate 10 (200 mg) over 2 minutes and stirring continued for 30 minutes. The mixture was allowed to reach room temperature and stirred for 16 hours. Water was added and the organic layer collected through a hydrophobic frit and evaporated to dryness. The residue was purified by flash chromatography on silica gel, eluting with a gradient of 0-100% ethyl acetate:cyclohexane over 20 minutes, followed by a gradient of 0-50% ethyl acetate: methanol over 10 minutes. Evaporation of the product containing fractions to dryness gave the title compound as clear glass (0.29 g). LCMS showed MH⁺=508, 510 (Bromine isotope); T_RET=2.68 min.

Intermediate 13: Ethyl 4-[(1{[(1,1-dimethylethyl)oxy]carbonyl}-4-piperidinyl)amino]-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

A solution of ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (14.8 g, 52.6 mmol, e.g. which can be as prepared in Intermediate 3, first or alternative preparation thereof) in N-methyl-2-pyrrolidinone (140 ml) was treated with N,N-diisopropylethylamine (22.9 ml, 131 mmol) followed by 1,1-dimethylethyl 4-amino-1-piperidinecarboxylate (11.6 g, 57.9 mmol, commercially available e.g. from AstaTech) and the mixture was heated at 120° C. for 24 hours. The reaction mixture was cooled and poured into aqueous lithium chloride solution (5% LiCl, 1 L) and the aqueous phase was extracted with ethyl acetate (3×250 ml). The combined organic extracts were dried (Na₂SO₄) and the solvent was evaporated. The residue, an oil, was purified by column chromatography using a column of silica gel (ART9385, 500 ml) made up in 4:1 hexane:ethyl acetate, eluting with 4:1 hexane:ethyl acetate (500 ml) and then 2:1 hexane:ethyl acetate until the product eluted. The fractions containing the product were pooled and the solvent was evaporated to give the title compound (18.55 g) as an oil which solidified on standing. LCMS m/z 446 [MH⁺]; T_RET=3.69 min.

Intermediate 14: 1,1-Dimethylethyl 4-{[1,6-d]ethyl-5-(hydroxymethyl)-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxylate

A solution of ethyl 4-[(1-{[(1,1-dimethylethyl)oxy]carbonyl}-4-piperidinyl)amino]-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (18.3 g, 41.1 mmol, e.g. which can be as prepared in Intermediate 13) in tetrahydrofuran (100 ml) was treated with lithium borohydride (LiBH₄, 2M in tetrahydrofuran, 40 ml, 80 mmol) followed by methanol (3.6 ml, 88.8 mmol), was heated under reflux for 3 hours, and then was cooled to about room temperature. To the cooled mixture was added a further portion of lithium borohydride (LiBH₄, 2M in tetrahydrofuran, 40 ml, 80 mmol) followed by methanol (3.6 ml, 88.8 mmol). The mixture was heated under reflux for 2 hours and allowed to cool to room temperature. Solid lithium borohydride (1.6 g, 73.5 mmol) was added followed by methanol (3.6 ml, 88.8 mmol), and the mixture was heated under reflux for 2 hours and allowed to cool overnight. The mixture was cooled in an ice/water bath, and treated with methanol (20 ml). After stirring for 10 min, water (10 ml) was added. When the effervescence ceased more water was added cautiously (500 ml total volume) and the mixture was stirred for 45 minutes. The mixture was partitioned between water and dichloromethane. The aqueous phase was separated and extracted with dichloromethane (×2). The combined organic extracts were washed with brine, dried (Na₂SO₄) and the solvent was evaporated. The residue was purified by column chromatography (800 ml of ART9385 silica gel, column made up using 1:1 hexane:ethyl acetate), using chloroform to load the mixture and eluting with hexane:ethyl acetate (1:1, 800 ml), hexane:ethyl acetate (1:2, 1800 ml) and finally neat ethyl acetate to complete elution of the product. The fractions containing the product were combined and the solvent was evaporated to give the title compound (12.4 g). LCMS m/z 404 [MH⁺]; T_RET=2.40 min.

Intermediate 15: 1,1-Dimethylethyl 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxylate

A suspension of 1,1-dimethylethyl 4-{[1,6-d]ethyl-5-(hydroxymethyl)-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxylate (14.0 g, 34.7 mmol, e.g. which can be as prepared in Intermediate 14) in N,N-dimethylformamide (110 ml) was treated with sodium azide (4.59 g, 70.6 mmol) and carbon tetrabromide (23.1 g, 69.7 mmol). The stirred suspension was cooled in an ice/water bath and a solution of triphenylphosphine (18.6 g, 70.9 mmol) in N,N-dimethylformamide (75 ml) was added dropwise over 30 minutes. The resulting yellow solution was allowed to warm to room temperature and was stirred for a further 3.5 hours. A solid separated during the stirring. The suspension was concentrated in vacuo to about ⅓ the original volume and partitioned between water (500 ml) and ethyl acetate (600 ml). The organic phase was separated and washed with water (×2). The combined aqueous phases were back-extracted with ethyl acetate. The combined organic extracts were then washed with 5% aqueous lithium chloride solution and were dried (Na₂SO₄), and the solvent was removed by evaporation. The residue was purified by column chromatography (800 ml of ART9385 silica gel, column made up in 1:1 hexane:ethyl acetate), loading the residue in dichloromethane, and eluting with 1:1 hexane:ethyl acetate. The fractions containing the product were combined and the solvent was evaporated to give the title compound as a white solid (12.6 g). LCMS m/z 429 [MH⁺]; T_RET=2.92 min.

Intermediate 16: 4-{[5-(Azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxamide

A solution of 1,1-dimethylethyl 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxylate (8.9 g, 20.8 mmol, e.g. which can be as prepared in Intermediate 15) in 1,4-dioxane (50 ml) was treated with 4M HCl in 1,4-dioxane (125 ml). After 2 hours the solvent was evaporated and the residue was partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution. The organic phase was collected and washed with saturated aqueous sodium bicarbonate solution. The combined aqueous phases were back-extracted with dichloromethane. The combined organic phases were dried (Na₂SO₄) and the solvent was evaporated to give an oil (LCMS showed MH⁺=329; T_RET=1.75 min). The oil was dissolved in dichloromethane (100 ml), and the solution was treated with N,N-diisopropylethylamine (6.1 ml, 35.0 mmol) followed by trimethylsilyl isocyanate (3.6 ml, 26.6 mmol, commercially available e.g. trimethylsilyl isocyanate 85% from Aldrich). The reaction mixture was stirred at room temperature overnight. Additional N,N-diisopropylethylamine (6.1 ml, 35.0 mmol) and trimethylsilyl isocyanate (3.6 ml, 26.6 mmol) was added. After stirring for a further 7 hours, additional trimethylsilyl isocyanate (3.6 ml) was added and stirring was continued over the weekend (e.g. this can be about 62 hours). Water (100 ml) was added and the mixture was stirred for 1 hour. The precipitated solid was collected by filtration, washed with water followed by diethyl ether, and then dried to give the title compound (2.21 g). LCMS m/z 372 [MH⁺]; T_RET=2.08 min.

Alternative Preparation of 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxamide

1,1-dimethylethyl 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxylate (5.14 g) is treated with a 4M solution of hydrogen chloride in dioxane (50 ml). The reaction mixture is left to stand for 2 hours. The solvent is evaporated and co-evaporated with dichloromethane (2×50 ml) then diethyl ether (2×50 ml) to give 5-(azidomethyl)-1,6-diethyl-N-4-piperidinyl-1H-pyrazolo[3,4-b]pyridin-4-amine, hydrochloride salt. This product is dissolved in dichloromethane (100 ml) and the solution is treated with DIPEA (6.3 ml) and trimethylsilyl isocyanate (1.8 ml), and then is left to stand at room temperature for 18 hours. Water (50 ml) is added and the precipitated solid is collected by filtration, washed with diethyl ether and dried to give 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxamide.

Intermediate 17: 4-{[5-(Aminomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxamide

10% Palladium on carbon (0.65 g), in a flask flushed with nitrogen, was treated with water (about 2 ml), ethanol (20 ml) and a suspension of 4-{[5-(azidomethyl)-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl]amino}-1-piperidinecarboxamide (4.1 g, 11.0 mmol, e.g. which can be as prepared in Intermediate 16) in ethanol (100 ml). Additional ethanol (200 ml) was used to wash the suspension into the flask. The suspension was stirred under an atmosphere of hydrogen for 21 hours. The mixture was filtered through celite to remove catalyst, and the filtrate was evaporated to dryness to give the title compound as a grey foam (3.8 g). LCMS m/z 346 [MH⁺]; T_RET=about 1.66 min.

Intermediate 18: 4-[(5-{[(8-Bromooctanoyl)amino]methyl}-1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide

A solution of Intermediate 17 (0.25 g) and triethylamine (0.1 ml) in chloroform (20 ml) cooled to 0° C. was treated with Intermediate 10 (175 mg) dropwise over 2 minutes and stirring continued for 30 minutes. The mixture was allowed to reach room temperature and stirred for 16 hours. Water was added, the organic layer collected through a hydrophobic frit and evaporated to dryness. The residue was purified by flash chromatography on silica gel, eluting with a gradient of 0-100% ethyl acetate:cyclohexane over 20 minutes, followed by a gradient of 0-50% methanol:ethyl acetate over 10 minutes. Evaporation of the product containing fractions to dryness gave the title compound as clear glass (0.29 g). LCMS showed MH⁺=550, 552 (Bromine isotope); T_RET=2.45 min.

Intermediate 29: Diethyl (1-chloroethylidene)propanedioate

To a cooled (10° C.) suspension of diethyl malonate (200 g, 1.41 mol) in dry acetonitrile (300 mL) was added anhydrous magnesium chloride (119.37 g, 1.26 mol, e.g. available from Lancaster) maintaining the temperature below 20° C. Triethylamine (348 ml) was added dropwise to the slurry followed by the dropwise addition of a solution of acetyl chloride (98.12 g, 1.25 mol) in acetonitrile (100 ml) maintaining the temperature at 10-15° C. Stirring was continued for 1 hour at 10-15° C. and the mixture allowed to warm to room temperature overnight.
Hydrochloric acid (1M) was added to the cooled reaction mixture (10° C.) until the pH of the mixture was about 1.0 (approx. 1.1 L was required). The mixture was extracted with diethyl ether (2×800 ml). The combined ethereal extracts were washed with hydrochloric acid (1M, 1×600 ml) and brine. Evaporation of the solvent under reduced pressure afforded diethyl acetylpropanedioate as the product (233.28 g) as an orange oil.
To the above keto-diester derivative (233 g) in phosphorus oxychloride (POCl₃, 2.2 L) was added tri-n-butylamine (250 ml) dropwise and the solution then heated at 120° C. for 7 hours. Excess phosphorus oxychloride was removed under reduced pressure; and the cooled reaction mixture extracted with a 1:2 mixture of hexane and diethyl ether (3×1.2 L). The combined organic extracts were washed with hydrochloric acid (1M, 2×1 L), NaOH solution (0.1M, 2×1 L), with water (2×1 L), brine (2×1 L) and dried (Na₂SO₄). Evaporation of the solvent under reduced pressure afforded the title compound (158 g) as a red oil which was used without further purification.

Intermediate 30: Ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

A mixture Intermediate 29 (158 g, 0.72 mol), Intermediate 1 (79 g, 0.71 mol) and triethylamine (196 ml) in toluene (2 L) was heated under reflux for 16 hrs. The reaction mixture was then cooled to room temperature, filtered and the solid residue washed thoroughly with toluene. From the combined filtrate and the washings, toluene was removed by evaporation under reduced pressure. The residue treated with phosphorus oxychloride (POCl₃, 2 L) and then heated under reflux for 16 hrs. Excess phosphorus oxychloride was removed under reduced pressure. The reaction mixture was diluted with ethyl acetate (1 L) and cooled to 10° C. Saturated aqueous sodium bicarbonate solution (800 ml) was added dropwise. The organic layer was separated, dried (Na₂SO₄) and evaporated to give an oil.
The crude product was purified by chromatography (silica gel, 60-120 mesh, 3 kg), eluting with 3% ethyl acetate in hexane. The desired fractions were combined and evaporated to give the title compound (76 g). 1H NMR (200 MHz, chloroform-d) 8 (delta) ppm 1.42 (3H, t, J=7.2 Hz), 1.50 (3H, t, J=7.3 Hz), 2.68 (3H, s), 4.47 (2H, q, J=7.3 Hz), 4.56 (2H, q, J=7.2 Hz), 8.04 (1H, s).

Alternative Preparation of ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

A mixture of 5-amino-1-ethylpyrazole (1.614 g, 14.5 mmol) and diethyl 2-(1-ethoxyethylidene)malonate [e.g. see J. Am. Chem. Soc., 1931, 53, 1836] (3.68 g) is heated at 150° C. under Dean Stark conditions for 5 hours. Phosphorous oxychloride (25 ml) is carefully added to the mixture and the resulting solution is heated at 130° C. under reflux for 18 hours. The mixture is concentrated in vacuo and the residual oil is carefully added, with cooling, to water (100 ml). The resulting mixture is extracted with dichloromethane (3×100 ml) and the combined organic extracts are dried over anhydrous sodium sulphate and concentrated in vacuo. The residual oil is purified by Biotage chromatography (silica; 90 g) eluting with 5% ethyl acetate in petroleum ether. Fractions containing the desired product are combined and concentrated in vacuo to give ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate.

Intermediate 31: Ethyl 1-ethyl-6-methyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Intermediate 30 (58 g, 217 mmol) in N-methyl-2-pyrrolidinone (380 ml) was treated with N,N-diisopropylethylamine (75 ml, 433 mmol) and a solution of tetrahydro-2H-pyran-4-amine (26.2 g, 260 mmol, e.g. available from Peakdale or Combi-Blocks) in N-methyl-2-pyrrolidinone (100 ml), and was then heated at 115° C. overnight. The cooled mixture was poured into water (2500 ml) and extracted with ethyl acetate (6×250 ml). The combined organic extracts were washed with water and brine, dried and evaporated. The residue was suspended in diethyl ether (about 150 ml) and the solid collected by filtration to give the title compound (44.5 g) as a white solid. LCMS m/z 333 [MH⁺]; T_RET=2.89 min.
The filtrate was evaporated, dissolved in ethyl acetate, washed with water and brine, dried and evaporated. Treatment with diethyl ether as described above gave a further quantity of the title compound (9.6 g). A further repeat of this procedure on the filtrate gave an additional quantity of the title compound (2.16 g).

Intermediate 32: [1-Ethyl-6-methyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

Intermediate 31 (26.9 g, 80.9 mmol) in dry dichloromethane (270 ml) under an atmosphere of nitrogen was cooled to 0° C. and treated with diisobutylaluminium hydride (162 ml of a 1.5M solution in toluene, 243 mmol). The addition took 27 minutes. The resulting pale yellow solution was stirred at 0° C. for 35 minutes and quenched by careful addition of about 20% aqueous potassium sodium tartrate solution (Rochelle's salt, 250 ml). This was exothermic and produced effervescence (temperature reached a maximum of 30° C.). After stirring for 20 min the solids were removed by filtration and washed with dichloromethane and ethyl acetate and the aqueous phase of the filtrate extracted firstly with dichloromethane then ethyl acetate. The combined organics were washed with water then brine, dried and evaporated to give 3 g of material. The aqueous phase was treated with more potassium sodium tartrate solution, concentrated and exhaustively extracted with ethyl acetate. The ethyl acetate extracts were combined, dried and evaporated to give the title compound (17.9 g) as a cream solid. LCMS m/z 291 [MH⁺]; T_RET=1.74, 1.81 min (split peak).

Intermediate 33: 5-(Azidomethyl)-1-ethyl-6-methyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

A suspension of Intermediate 32 (9.7 g, 33.4 mmol) in toluene (100 ml) was treated dropwise with thionyl chloride (SOCl₂, 36.6 ml, 500 mmol) over 10 minutes resulting in a gummy lump. The mixture was heated to 80° C. for 2.5 hours by which time the lump had broken down to be a pale brown suspension. The mixture was cooled, then evaporated and the residue was azeotroped with more toluene (about 20 ml). The resultant pale brown solid was suspended in dimethylsulphoxide (75 ml) and treated with sodium azide (3.25 g, 50.1 mmol); the mixture became darker and slightly more translucent. After 2 hours the mixture was partitioned between saturated aqueous sodium bicarbonate solution and ethyl acetate, the layers separated and the aqueous phase extracted with more ethyl acetate. The combined organics were washed with water then brine, dried and evaporated. The residue was purified by silica gel chromatography (800 g) eluting with 1:1 cyclohexane:ethyl acetate. The fractions containing the product were pooled and evaporated to give the title compound (7.6 g). 1H NMR (400 MHz, CDCl₃) δ (delta) ppm 1.51 (3H, t), 1.68 (2H, m), 2.16 (2H, m), 2.64 (3H, s), 3.61 (2H, m), 4.05 (2H, m), 4.13 (1H, m), 4.45 (2H, s), 4.47 (2H, q), 4.96 (1H, d), 7.88 (1H, s).

Intermediate 34: 5-(Aminomethyl)-1-ethyl-6-methyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

10% palladium on carbon (50% wet, 2.1 g) was treated with ethanol (20 ml) followed by a solution of Intermediate 33 (10.48 g) in ethanol (180 ml), and was hydrogenated at room temperature and pressure overnight. The catalyst was removed by filtration, washing through with more ethanol, and the solvents were removed under reduced pressure to give the title compound (9.0 g) as a grey foam: 1H NMR (400 MHz, d6 DMSO) δ (delta) ppm 1.36 (3H, t), 1.59 (2H, m), 2.0 (2H, m), 2.50 (3H, s), 3.37 (2H, br s), 3.62 (2H, m), 3.89 (2H, s), 3.91 (2H, m), 4.14 (1H, m), 4.33 (2H, q), 7.62 (1H, d), 8.02 (1H, s).

Intermediate 48: 5-(Aminomethyl)-1-ethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine hydrochloride

1-Ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxamide (0.59 g, 2.04 mmol, e.g. preparable according to WO2004/056823) was suspended in dry tetrahydrofuran (20 ml) and borane-tetrahydrofuran complex (10.2 ml, 1M soln in tetrahydrofuran) was added. The reaction was heated under reflux under nitrogen for 4 hours. The mixture was cooled, quenched with methanol (20 ml), and allowed to stand at room temperature over the weekend. The solvent was evaporated in vacuo and the residue dissolved in methanol and applied to a 20 g SCX cartridge, eluting with methanol followed by 2M ammonia/methanol. The ammonia/methanol fractions were combined and evaporated to gave a yellow oil (0.38 g). The oil was dissolved in methanol, 2M hydrochoric acid (5 ml) was added, and the mixture was heated at 70° C. for 2 hours. The mixture was cooled and solvent evaporated to give an orange oil (0.4 g). Purification by flash chromatography, eluting with 0-30% methanol and 1% triethylamine in dichloromethane over 20 minutes, gave the title compound as an impure oil (0.32 g). LCMS showed MH⁺=276; T_RET=1.72 min.
The impure intermediate (0.31 g) was dissolved in methanol (10 ml) and di-t-butyldicarbonate (0.25 g, 1.13 mmol) and triethylamine (0.16 ml, 1.13 mmol) were added. The mixture was left standing at room temperature for 16 hours. The solvent was evaporated and the residue partitioned between dichloromethane (10 ml) and water (10 ml). The organic phase was collected by passing through a hydrophobic frit and the solvent evaporated to give the impure BOC-protected amine intermediate as an orange oil (0.26 g), which was used without further purification. LC/MS showed MH⁺=376; T_RET=2.39 mins.
The BOC-protected intermediate (58 mg, including material from another preparation) was treated with a 4M solution of HCl in 1,4-dioxane (1 ml) and the resulting mixture was left standing at room temperature for 16 hours. The solvent was removed by evaporation to give the title compound as a beige coloured solid (55 mg). LCMS showed MH⁺=276; T_RET=1.66 min.

OPTIONAL INTERMEDIATES

In this Optional Intermediates section, “Intermediates” generally represent syntheses of intermediate compounds which (in some cases) might theoretically be usable in the synthesis of compounds of formula (I) or salts thereof, but which have not necessarily been used to prepare specific compounds of formula (I) or salts thereof (and in most or all cases they have not been so used).

Optional Intermediate 60 [1-ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

A solution of 1M diisobutylaluminium hydride in dichloromethane (80 ml) is added dropwise to a stirred solution of ethyl 1-ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate [e.g. see Intermediate 32 and/or Example 3 of WO 2004/024728 A2] (13.8 g) in dichloromethane (75 ml) at 0° C. under nitrogen. The reaction mixture is maintained below 5° C. during the addition, and is then stirred for 0.5 h at 0° C. The mixture is then quenched by addition of aqueous potassium sodium tartrate (10% solution), diluted with water (150 ml) and the organic phase separated. The aqueous phase is extracted with ethyl acetate (2×250 ml) and the combined organics are dried (magnesium sulphate) and evaporated. The residue is purified by column chromatography on silica gel eluting with a gradient of 0-100% ethyl acetate in cyclohexane followed by 0-20% methanol in ethyl acetate to give Intermediate 60.

Optional Intermediate 61 5-(chloromethyl)-1-ethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

Intermediate 60 (80 mg) is treated with thionyl chloride (1 ml) and heated at 80° C. for 1 h then allowed to cool. The orange solution is evaporated to dryness and the residue azeotroped with toluene (2×5 ml) to give Intermediate 61.

Optional Intermediate 62 5-(azidomethyl)-1-ethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine

A solution of Intermediate 61 (50 mg) in anhydrous dimethylsulphoxide (0.2 ml) is treated with lithium azide (9 mg) and the solution is stirred at room temperature for 20 h. A further portion of lithium azide (15 mg) is then added, and after a further day stirring at room temperature, water (0.25 ml) is added. The solution is extracted with dichloromethane (2×5 ml) and the combined organic extracts are passed through a hydrophobic frit (6 ml) and then are blown to dryness. The residue is dissolved in dichloromethane (0.5 ml) and applied to an SPE cartridge (silica; 1 g). The cartridge is eluted with 50% ethyl acetate in cyclohexane and fractions containing the desired material are combined and blown to dryness to give Intermediate 62.

Optional Intermediate 63 1-ethyl-N⁴-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridine-4,5-diamine

A solution of Intermediate 62 (0.351 g) in ethanol (30 ml) is added to palladium on carbon (5% wet, 0.050 g) and the mixture is stirred at room temperature for 20 hours under an atmosphere of hydrogen. The mixture is filtered through a glass fibre filter and through celite, which is then washed with ethanol (50 ml). The combined filtrates and washings are concentrated in vacuo to give Intermediate 63.


		One or two possible published
Optional		reference(s) to (e.g. synthetic
Intermediate	Structure of	reference to), or one possible
Number	compound	source of, the compound

100		Intermediate 8A of WO 2004/024728 A2 (Glaxo Group Limited)

101		Intermediate 6 of WO 2004/024728 A2 (Glaxo Group Limited), which refers to WO 00/42011

102		Intermediate 32 and/or Example 3 of WO 2004/024728 A2 (Glaxo Group Limited); or Intermediate 4 of WO 2005/058892 A1 (Glaxo Group Limited)

103		Intermediate 5 of WO 2005/058892 A1 (Glaxo Group Limited)

104		Example 207 of WO 2004/024728 A2 (Glaxo Group Limited); or Intermediate 6 of WO 2005/058892 A1 (Glaxo Group Limited)

105		Example 204 of WO 2004/024728 A2 (Glaxo Group Limited)

106		Example 205 of WO 2004/024728 A2 (Glaxo Group Limited)

107		Example 652 of WO 2004/024728 A2 (Glaxo Group Limited)

108		Intermediate 12 of WO 2005/058892 A1 (Glaxo Group Limited)

109		Intermediate 102 of WO 2005/058892 A1 (Glaxo Group Limited)

110		Intermediate 103 of WO 2005/058892 A1 (Glaxo Group Limited)

111		Intermediate 104 of WO 2005/058892 A1 (Glaxo Group Limited)

112		Intermediate 112 of WO 2005/058892 A1 (Glaxo Group Limited)

113		Intermediate 113 of WO 2005/058892 A1 (Glaxo Group Limited)

114		Intermediate 114 of WO 2005/058892 A1 (Glaxo Group Limited)

115		Intermediate 115 of WO 2005/058892 A1 (Glaxo Group Limited)

116		Intermediate 116 of WO 2005/058892 A1 (Glaxo Group Limited)

117		Intermediate 117 of WO 2005/058892 A1 (Glaxo Group Limited)

118		Intermediate 118 of WO 2005/058892 A1 (Glaxo Group Limited)

119		Intermediate 119 of WO 2005/058892 A1 (Glaxo Group Limited)

120		Intermediate 146 of WO 2005/058892 A1 (Glaxo Group Limited)

121		Intermediate 147 of WO 2005/058892 A1 (Glaxo Group Limited)

122		Intermediate 148 of WO 2005/058892 A1 (Glaxo Group Limited)

123		Intermediate 149 of WO 2005/058892 A1 (Glaxo Group Limited)

124		Intermediate 150 of WO 2005/058892 A1 (Glaxo Group Limited)

125		Intermediate 151 of WO 2005/058892 A1 (Glaxo Group Limited)

126		Intermediate 155 of WO 2005/058892 A1 (Glaxo Group Limited)

127		Intermediate 156 of WO 2005/058892 A1 (Glaxo Group Limited)

128		Intermediate 157 of WO 2005/058892 A1 (Glaxo Group Limited)

129		Intermediate 159 of WO 2005/058892 A1 (Glaxo Group Limited)

130		Intermediate 160 of WO 2005/058892 A1 (Glaxo Group Limited)

131		Intermediate 161 of WO 2005/058892 A1 (Glaxo Group Limited)

132		Example 185 of WO 2004/024728 A2 (Glaxo Group Limited); or Intermediate 171 of WO 2005/058892 A1 (Glaxo Group Limited)

133		Example 20 of WO 2004/024728 A2 (Glaxo Group Limited)

134		Example 186 of WO 2004/024728 A2 (Glaxo Group Limited)

135		Fluka Chemie AG, Germany (CAS 111769-27-8)

136		E. Merck, Germany; or E. Merck (Merck Ltd), Hunter Boulevard, Magna Park, Lutterworth, Leicestershire LE17 4XN, United Kingdom (CAS 104530-80-5)

137		Intermediate 11 of WO 2004/024728 A2, and optionally reference cited therein

138		Intermediate 12 of WO 2004/024728 A2, and optionally references cited therein

139		Sigma Aldrich Library of Rare Chemicals (SALOR) (CAS-6338-70-1)

140		Intermediate 14 of WO 2004/024728 A2, and optionally references cited therein

141		Intermediate 3 of WO 2004/024728 A2 (Glaxo Group Limited)

142		Intermediate 25 of WO 2004/024728 A2 (Glaxo Group Limited)

143		Example 8 of WO 2004/024728 A2 (Glaxo Group Limited)

144		Example 9 of WO 2004/024728 A2 (Glaxo Group Limited)

145		Example 10 of WO 2004/024728 A2 (Glaxo Group Limited)

146		Example 11 of WO 2004/024728 A2 (Glaxo Group Limited)

147		Example 13 of WO 2004/024728 A2 (Glaxo Group Limited)

148		Example 14 of WO 2004/024728 A2 (Glaxo Group Limited)

149		Example 190 of WO 2004/024728 A2 (Glaxo Group Limited)

150		Intermediate 54 of WO 2004/024728 A2 (Glaxo Group Limited)

151		Intermediate 58A of WO 2004/024728 A2 (Glaxo Group Limited)

152		Intermediate 62 of WO 2004/024728 A2 (Glaxo Group Limited)

153		Intermediate 63 of WO 2004/024728 A2 (Glaxo Group Limited)

154		AB Chem, Inc., Canada (mixture of cis and trans); or J. Chem. Soc., Perkin Trans. 1, 1994, 537

155	as Intermediate 154, but racemic cis-	J. Chem. Soc., Perkin Trans 1,
	isomer, i.e. racemic cis-(3-hydroxy-	1994, 537
	cyclohex-1-yl)-amine	(discloses a 3.3:1 cis:trans
		mixture)

156		Aldrich; or TCI-America

157		U.S. Pat. No. 4,219,660

158		Aldrich

159		Aldrich

160		Aldrich

161		Pfaltz-Bauer

162		J. Org. Chem., 1985, 50(11), 1859

163		WO 99/12933

164		EP 1188744

165		Sigma-Aldrich Company Ltd

166*		J. Med. Chem., 1994, 37(17), 2360

167*		Aldrich

168*		Aldrich

169*		Aldrich

170*		Peakdale Molecular Ltd

171		AstaTech

172

173		Syngene or AstaTech

174		Fluka

175		Aldrich

176		Aldrich

EXAMPLES

Table of Examples

Example
No.	Name

5	4-({1,6-diethyl-5-[({8-[(2-
	hydroxyethyl)(methyl)amino]octanoyl}amino)methyl]-1H-
	pyrazolo[3,4-b]pyridin-4-yl}amino)-1-piperidinecarboxamide
	trifluoroacetate (salt)
7	4-[(1,6-diethyl-5-{[(8-{(2R)-2-[(methyloxy)methyl]-1-
	pyrrolidinyl}octanoyl)amino]methyl}-1H-pyrazolo[3,4-
	b]pyridin-4-yl)amino]-1-piperidinecarboxamide
	trifluoroacetate
8	4-[(1,6-diethyl-5-{[(8-{(2S)-2-[(methyloxy)methyl]-1-
	pyrrolidinyl}octanoyl)amino]methyl}-1H-pyrazolo[3,4-
	b]pyridin-4-yl)amino]-1-piperidinecarboxamide
	trifluoroacetate
13	N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-
	pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-[(2-
	hydroxyethyl)(methyl)amino]octanamide trifluoroacetate (salt)
15	N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-
	pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2R)-2-
	[(methyloxy)methyl]-1-pyrrolidinyl}octanamide
	trifluoroacetate
16	N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-
	pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2S)-2-
	[(methyloxy)methyl]-1-pyrrolidinyl}octanamide
	trifluoroacetate

Examples 5, 7, 8, 13, 15 and 16

0.04 mmol of the appropriate (8-bromooctanoyl)amino-alkylating agent (selected from those listed below) in N,N-dimethylformamide (0.5 ml) was treated with a solution of the appropriate amine (HNR⁵R⁶wherein NR⁵R⁶is as defined in the table below; 0.08 mmol) in N,N-dimethylformamide (0.5 ml) followed by N,N-diisopropylethylamine (0.04 ml). The reaction mixture was heated at 80° C. for 16 hours and the solvent was removed in vacuo. The residue was purified by mass directed preparative HPLC (Method B) to give the appropriate title compound (with a structure as shown in the table below) as a trifluoroacetate salt.
(8-Bromooctanoyl)amino-alkylating agents and amounts used:

- 8-bromo-N-{[1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}octanamide (162.7 mg/8=20.34 mg, 0.04 mmol, e.g. which can be as prepared in Intermediate 12); and
- 4-[(5-{[(8-bromooctanoyl)amino]methyl}1,6-diethyl-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide (176.2 mg/8=22.03 mg, 0.04 mmol, e.g. which can be as prepared in Intermediate 18).

				Starting	NR⁵R⁶	One
				material	(wherein the	possible
				can be	connecting	Source
Example				as pre-	nitrogen atom is	of	M-H	T_RET
No.	R³	Ar	Q³	pared in	underlined)	HNR⁵R⁶	ion	(min)

5	(w1)	Q³ is a bond	Inter- mediate 18	Aldrich	543	1.94

7	(w1)	Q³ is a bond	Inter- mediate 18	Aldrich	583	2.03

8	(w1)	Q³ is a bond	Inter- mediate 18	Aldrich	583	2.03

13	(w1)	Q³ is a bond	Inter- mediate 12	Aldrich	501	2.02

15	(w1)	Q³ is a bond	Inter- mediate 12	Aldrich	541	2.12

16	(w1)	Q³ is a bond	Inter- mediate 12	Aldrich	541	2.12

Claims

1-52. (canceled)

53. A compound of formula (I) or a salt thereof:

wherein Ar has the sub-formula (w), (y), (z1) or (z2):

wherein:

Q¹is NH or NMe, and Q²is —C(O)—, —S(O)₂—, —C(O)NH— or —C(O)NMe-;

or when Q¹is a bond or —O—, then Q²is a bond;

or when Q¹is —C(O)— then Q²is NH or NMe;

or when Q¹is —S(O)₂— then Q²is NH, NMe or a bond;

Q³is a bond, NH or NMe;

L is (CH₂)_nwherein n is 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13;

or L is —(CH₂)_m ¹—O—(CH₂)_m ²—, wherein it is the —(CH₂)_m ²— which is bonded to the NR⁵R⁶group, and wherein m¹is 1, 2, 3, 4, 5, 6, 7, 8 or 9, and m²is 2, 3, 4, 5, 6, 7, 8 or 9; provided that m¹+m²is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, and provided that when m¹is 1 then Q²is —C(O)— and Q³is a bond;

R⁵is a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, —CH₂CH₂OH, —CH₂CH(Me)OH, —CH₂CH₂CH₂OH, —CH₂CH₂OMe, or —CH₂CH₂CH₂OMe;

R⁶is C_1-4alkyl, or R⁶is C_1-4alkyl substituted by one OH or OC_1-3alkyl substituent which is not substituted at the alkyl carbon atom which is bonded to the nitrogen atom of the NR⁵R⁶group;

or R⁵and R⁶taken together are —(CH₂)₂—X—(CH₂)₂—, —(CH₂)₂—X—(CH₂)₃—, —(CH₂)_{p 1}—, —CHR^7a—(CH₂)_p ²—, or —(CH₂)_p ³—CHR^7b—(CH₂)_p ⁴—; in which:

X is O or NR⁸wherein R⁸is hydrogen or C_1-3alkyl;

R^7ais —CH₂OH, —CH₂OC_1-3alkyl, —CH₂CH₂OH, —CH₂CH₂OC_1-3alkyl, or C_1-3alkyl;

R^7bis OH, OC_1-3alkyl, —CH₂OH, —CH₂OC_1-3alkyl, —CH₂CH₂OH, —CH₂CH₂OC_1-3alkyl, or C_1-3alkyl;

p¹is 4, 5 or 6,

p²is 3, 4 or 5,

p³is 1 or 2 and p⁴is 2, 3 or 4, provided that p³+p⁴is 3, 4 or 5;

and wherein, in sub-formula (y):

A, B, D, E and F independently are C—H or nitrogen (N); wherein one or two of A, B, D, E and F are nitrogen (N) and the remainder of A, B, D, E and F are C—H;

the Q¹-Q²-L-NR⁵R⁶group of sub-formula (y) is substituted at a ring carbon atom of the six-membered heteroaryl ring of sub-formula (y);

and wherein sub-formulae (z1) and (z2) are connected to the carbonyl carbon atom of formula (I) at a ring carbon atom within (z1) and (z2);

and wherein, in sub-formulae (z1) and (z2):

G is O or S or NR⁹wherein R⁹is a hydrogen atom (H) or methyl;

J is C—R^9J, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N),

M is C—R^9M, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N), and

Q is C—R^9Q, C-[connection to carbonyl carbon atom of formula (I)], or nitrogen (N);

no more than two of J, M and Q are nitrogen (N);

R^9J, R^9Mand R^9Qindependently are a hydrogen atom (H) or methyl; provided that no more than one of R^9J, R^9Mand R^9Qis methyl;

R¹is C_1-3alkyl, —CH₂—C_1-2fluoroalkyl, or —CH₂CH₂OH;

R²is a hydrogen atom (H), methyl, ethyl, n-propyl, isopropyl, n-butyl, C_1-2fluoroalkyl, cyclopropyl, cyclobutyl, or (cyclopropyl)methyl-;

R⁴is a hydrogen atom (H), methyl or ethyl; and

R³is optionally substituted C_4-7cycloalkyl, or optionally substituted mono-unsaturated-C_5-7cycloalkenyl, or an optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc), or a bicyclic group of sub-formula (ee);

in which n¹and n²independently are 1 or 2; and in which Y is O, S, SO₂, or NR¹⁰; where R¹⁰is a hydrogen atom (H), methyl, C(O)NH₂, C(O)-methyl, or C(O)—C₁fluoroalkyl;

wherein, when R³is optionally substituted C_4-7cycloalkyl, then R³is C_4-7cycloalkyl optionally substituted on a ring carbon(s) with one or two substituents independently being: oxo (═O); OH; methoxy; C₁fluoroalkoxy; NH₂; C_1-2alkyl; C₁fluoroalkyl; —CH₂OH; —CH(Me)OH; —CH₂CH₂OH; —CH₂NH₂; —C(O)OH; —C(O)NHR²⁴wherein R²⁴is H or methyl; —C(O)R²⁵wherein R²⁵is methyl; fluoro; hydroxyimino (═N—OH); or (C_1-2alkoxy)imino (═N—OR²⁶where R²⁶is C_1-2alkyl); and wherein any OH, methoxy, fluoroalkoxy or NH₂substituent is not bonded to the R³ring carbon bonded to the —NH— group of formula (I);

or when R³is the optionally substituted heterocyclic group of sub-formula (aa), (bb) or (cc), then R³is the heterocyclic group of sub-formula (aa), (bb) or (cc) optionally substituted on a ring carbon(s) with one or two oxo (═O) substituents; or

or when R³is optionally substituted mono-unsaturated-C_5-7cycloalkenyl, then the cycloalkenyl is optionally substituted on a ring carbon with one substituent being fluoro or methyl, and the R³ring carbon bonded to the —NH— group of formula (I) does not partake in the cycloalkenyl double bond;

or when R³is the heterocyclic group of sub-formula (aa) and Y is NR¹⁰, then R¹⁰is not C(O)-methyl, or C(O)—C₁fluoroalkyl; and

when R³is the heterocyclic group of sub-formula (bb) and Y is NR¹⁰, then R¹⁰is not methyl; and

when R³is the heterocyclic group of sub-formula (cc), then Y is O, S, SO₂or NR¹⁰wherein R¹⁰is H or methyl;

and wherein:

when R³is optionally substituted C_4-7cycloalkyl, then any —C(O)NHR²⁴or —C(O)R²⁵substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or

at the 3- or 4-position of a R³cyclopentyl ring; or at the 4-position of a R³cyclohexyl ring; or at the 3-, 4-, 5- or 6-position of a R³cycloheptyl ring wherein, in this connection, the 1-position of the R³cycloalkyl ring is deemed to be the connection point to the —NH— in formula (I), that is the ring atom connecting to the —NH— in formula (I);

and wherein:

when R³is optionally substituted C_4-7cycloalkyl, then any OH, methoxy, fluoroalkoxy, —CH₂OH, —CH(Me)OH, —CH₂CH₂OH, —CH₂NH₂, or —C(O)OH substituent on a ring carbon is: at the 3-position of a R³cyclobutyl ring; or at the 3- or 4-position of a R³cyclopentyl ring; or at the 3-, 4- or 5-position of a R³cyclohexyl ring; or at the 3-, 4-, 5- or 6-position of a R³cycloheptyl ring.

54. A compound or salt as claimed in claim 53, wherein R¹is ethyl.

55. A compound or salt as claimed in claim 53, wherein R²is ethyl.

56. A compound or salt as claimed in claim 53, wherein, when R³is a heterocyclic group of sub-formula (aa), (bb) or (cc), then Y is O or NR¹⁰.

57. A compound or salt as claimed in claim 53, wherein, when R³is a heterocyclic group of sub-formula (aa), (bb) or (cc), then R³is the heterocyclic group of sub-formula (bb) and n¹is 1.

58. A compound or salt as claimed in claim 53, wherein NHR³is sub-formula (c), (h), (k2), (k3), (n), (o), (o2), (p9) or (p13).

59. A compound or salt as claimed in claim 58, wherein R³is tetrahydro-2H-pyran-4-yl or 1-(aminocarbonyl)-4-piperidinyl.

60. A compound or a salt thereof as claimed in claim 53, wherein R⁴is hydrogen.

61. A compound or salt thereof as claimed in claim 53, wherein Ar has the sub-formula (w).

62. A compound or salt thereof as claimed in claim 53, herein Q³is a bond.

63. A compound or salt thereof as claimed in claim 53, wherein L is (CH₂)_n.

64. A compound or salt thereof as claimed in claim 53, wherein n is 6, 7, 8 or 9.

65. A compound or a salt thereof, which is:

4-({1,6-diethyl-5-[({8-[(2-hydroxyethyl)(methyl)amino]octanoyl}amino)-methyl]-1H-pyrazolo[3,4-b]pyridin-4-yl}amino)-1-piperidinecarboxamide,

4-[(1,6-diethyl-5-{[(8-{(2R)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanoyl)amino]methyl}-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide,

4-[(1,6-diethyl-5-{[(8-{(2S)-2-[(methyloxy)methyl]-1-pyrrolidinyl}-octanoyl)amino]methyl}-1H-pyrazolo[3,4-b]pyridin-4-yl)amino]-1-piperidinecarboxamide,

N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-[(2-hydroxyethyl)(methyl)amino]octanamide,

N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2R)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanamide, or

N-{[1,6-d]ethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methyl}-8-{(2S)-2-[(methyloxy)methyl]-1-pyrrolidinyl}octanamide.

66. A method of treatment and/or prophylaxis of an inflammatory and/or allergic disease in a patient in need thereof, which method comprises administering to the patient a therapeutically effective amount of a compound of formula (I) as defined in claim 53 or a pharmaceutically acceptable salt thereof.

67. A method as claimed in claim 66, wherein the disease is chronic obstructive pulmonary disease (COPD), asthma or rhinitis (such as allergic and/or non-allergic rhinitis) in a human.

68. A pharmaceutically acceptable composition comprising a compound or pharmaceutically acceptable salt of formula (I) according to claim 53 and a pharmaceutically acceptable excipient.