WO2001002364A1 - New npy antagonists - Google Patents

Abstract

There is provided compounds of formula (I) wherein n, Ar?1, R1, R2, R3, R4, R5 and R6¿ have meanings given in the description, which are useful as antagonists of neuropeptide Y and in particular in the treatment of cardiovascular diseases, for example vasoconstriction.

Description

NEW NPY ANTAGONISTS

Field of the Invention

This invention relates to novel pharmaceutically useful compounds, in particular antagonists of neuropeptide Y, the use of such compounds as medicaments, pharmaceutical compositions containing them and synthetic routes to their production.

Background

Neuropeptide Y (NPY) is a peptide consisting of 36 amino acids. In - recent years it has been established that NPY is an important co- transmitter in the peripheral sympathetic nervous system.

It has been postulated (see Pharmacological Reviews (1996) 48, 113) that the effects of sympathetic nerve activation are not only due to the neuronal release of noradrenaline but may also be the result of a simultaneous release of NPY from the sympathetic nerve terminal.

Released NPY is known to elicit marked constriction of blood vessels in both the heart (coronary arteries) and in most peripheral organs. This vasoconstrictive effect of NPY is believed to be mediated by a receptor sub-type known as Y_t .

Released NPY may also act on autonomic nerve endings to inhibit the release of neurotransmitters and, in doing so, reduce the cardiac vagal tone as a result of decreased acetylcholine release. This effect of NPY is believed to be mediated by a receptor sub-type known as Y₂. Other NPY-receptor sub-types, including the Y₃, Y₄, Y₅ and Y₆ sub- receptors, have been identified. The precise functions of these sub- receptors have not been identified in any detail, but the Y₅ sub-receptor is thought to be involved in feeding and eating regulation (see Exp. Opin. Invest. Drugs, 6, 437 (1997)).

Increased plasma concentrations of NPY have been found in several cardiovascular diseases including angina pectoris, myocardial infarction, congestive heart failure and hypertension. Further, emotional stress has been shown to cause a significant increase in plasma NPY levels (see Circulation (1994) 90, 1-268, Abstract No. 1445). Such observations suggest a significant pathogenic role for NPY in ischemic heart disease and hypertension. Moreover, by simultaneously causing coronary vasoconstriction and reduced vagal tone, NPY may predispose a patient to ventricular fibrillation and sudden cardiac death.

Effective NPY antagonists would therefore be expected to be useful in the treatment of inter alia cardiovascular diseases.

Prior Art

Non-peptide antagonists of NPY have been disclosed in inter alia International Patent Applications WO 94/17035, WO 97/19911, WO 97/19913, WO 97/19914, WO 96/22305, and WO 99/15498.

In particular, International Patent Application WO 99/15498 discloses certain amino acid derivatives, including (R)-N²-(diphenylacetyl)-N- (phenylmethyl)arginine amide derivatives, as antagonists of NPY. The substitution of the guanidinoalkyl group in the arginine residue for an aminopyridinealkyl moiety is neither mentioned nor suggested.

Surprisingly we have found that novel compounds comprising an aminopyridinealkyl group in place of the above-mentioned guanidinoalkyl group possess NPY antagonist activity.

Disclosure of the Invention

According to the invention there is provided a compound of formula I,

R⁴

wherein

n represents 1, 2 or 3;

Ar¹ represents a structural fragment of the formula

or represents 1- or 2-naphthyl, which latter group is optionally substituted by one or more substituents selected from OH, halo and C_1-7 alkoxy;

R⁷ represents H or OH;

R⁸ represents H, halo, C_1-7 alkyl, -(CH₂)_mOR¹⁶, -(CH₂)_mN(R¹⁶)R¹⁷, -(CH₂)_pC(0)N(R^I6)R¹⁷, -(CH₂)_pC(0)N(R¹⁷)CH₂C(0)OR¹⁶,

-(CH₂)_pN(R^l8)C(0)N(R¹⁶)R¹⁷, -(CH₂)_pN(R¹⁷)C(0)N(R¹⁸)CH₂C(0)OR¹⁶,

-(CH₂)_pN(R¹⁷)C(0)OR^16a, -0(CH₂)_pC(0)OR¹⁶, -N(R¹⁷)(CH₂)_pC(0)OR¹⁶, or, together with either of R⁹ or R^9a, forms a methylenedioxy group;

R⁹ and R^9a independently represent H, halo, OH, C_1-7 alkyl or C_1-7 alkoxy, and/or one of R⁹ and R^9a may, together with R⁸, form a methylenedioxy group;

R¹⁶ represents H, C_1-7 alkyl or -(CH₂)_q-phenyl;

R^16a represents C_1-7 alkyl or -(CH₂)_q-phenyl; m represents 0, 1, 2, or 3; p represents 1 , 2, 3 or 4; q represents 0 or 1 ;

R¹ represents H, C(0)NH₂ or C alkyl (optionally substituted and/or terminated by one or more substituents selected from hydroxy and amino);

R⁴ represents a structural fragment of formula II,

R¹⁰ and R¹¹ independently represent H or C_M alkyl; R⁵ and R⁶ independently represent one or more optional substituents selected from OH, C alkyl, C_M alkoxy, halo, N(R¹ )R¹³, -N(R¹⁷)CH₂C(0)OR¹⁴ and OCH₂C(0)OR¹⁵;

R², R³, R¹², R¹³, R¹⁴, R¹⁵, R¹⁷ and R¹⁸ independently represent, at each occurrence when used herein, H or .γ alkyl;

or a pharmaceutically acceptable derivative thereof (which compounds and derivatives are hereinafter referred to as "the compounds of the invention").

Pharmaceutically acceptable derivatives include solvates and salts. Particular salts that may be mentioned include those of hydrochloric, acetic, trifluoroacetic and camphorsulphonic acid.

The compounds of the invention may exhibit tautomerism. All tautomeric forms and mixtures thereof are included within the scope of the invention.

The compounds of the invention may also contain one or more asymmetric carbon atoms and may therefore exhibit optical and/or diastereoisomerism. Diastereoisomers may be separated using conventional techniques, e.g. chromatography or fractional crystallisation. The various stereoisomers may be isolated by separation of a racemic or other mixture of the compounds using conventional, e.g. fractional crystallisation of a diastereomeric salt or chiral HPLC techniques. Alternatively the desired optical isomers may be made by reaction of the appropriate optically active starting materials under conditions which will not cause racemisation or epimerisation, or by derivatisation, for example with a homochiral acid followed by separation of the diastereomeric esters by conventional means (e.g. HPLC, chromatography over silica). All stereoisomers, including mixtures thereof, are included within the scope of the invention.

Alkyl groups which R\ R², R\ R⁵, R⁶, R⁸, R⁹, R^9a, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R^16a, R¹⁷ and R¹⁸ may represent; and alkoxy groups which R⁵, R⁶ and R⁹ and R^9a may represent and with which Ar¹ (when it represents naphthyl) may be substituted, may be linear or, when there is a sufficient number (i.e. three) of carbon atoms, be branched and/or cyclic. Further, when there is a sufficient number (i.e. four) of carbon atoms, such alkyl and alkoxy groups may also be part cyclic/acyclic. Such alkyl and alkoxy groups may also be saturated or, when there is a sufficient number (i.e. two) of carbon atoms, be unsaturated and/or interrupted by oxygen. Such alkyl and alkoxy groups may also be substituted by one or more fluoro groups.

Further, alkyl groups which R¹⁶, R¹⁷ and R¹⁸ may represent may also be substituted by one or two OH groups, provided that OH is not attached to the carbon atom of that alkyl group that is also attached to the rest of the group of which R¹⁶, R¹⁷ or R¹⁸ (as appropriate) forms a part.

-(CH₂)- containing chains which R⁸, R¹⁶ and R^16a may include, may, in the -(CH₂)- chain part, be linear or, when there is a sufficient number (i.e. two) of carbon atoms, be branched. Such -(CH₂)- containing chains may also be saturated or, when there is a sufficient number (i.e. two) of carbon atoms, be unsaturated (in which case hydrogen atoms on adjacent carbon atoms in the chain are not present) and/or interrupted by oxygen.

As used herein, the term "halo" includes fluoro, chloro, bromo or iodo. For the avoidance of doubt, when a compound of formula I may comprise more than one of the substituents identified herein, the identity of each of those substituents is independent of the identity/identities of the other(s). For example, when a compound of formula I is provided in which R⁸ represents -(CH₂)_mN(R¹⁶)R¹⁷ and R⁵ represents -N(R¹⁷)CH₂C(0)OR¹⁴, then the two R¹⁷ substituents are not necessarily the same (though this possibility is not excluded).

Wavy lines on carbon atoms in e.g. the structural fragment

signify bond positions of the fragments.

Abbreviations are listed at the end of this specification.

Compounds of the invention that may be mentioned include those in which R⁸ does not represent C ₁ alkyl.

Preferred compounds of formula I include those wherein: n represents 1 ; R¹ represents H or methyl; R² represents H; R³ represents H or methyl; R⁴ represents a structural fragment of formula

R⁵ is either absent or represents a single substituent selected from OH, halo, methyl and methoxy; R⁶ is either absent or represents a single substituent selected from OH, halo, methyl and methoxy;

R⁷ represents H;

R⁸ represents OCH₃, halo, -CH₂C(0)NH₂, -CH₂N(H)C(0)N(R¹⁶)(R¹⁷),

NH₂ or OH; R⁹ represents H;

R^9a represents H;

R¹⁰ represents H;

R¹¹ represents H;

R¹⁶ represents H, C_1-7 alkyl, phenyl or benzyl; R¹⁷ represents H or methyl.

Preferred compounds of the invention include the compounds of the Examples disclosed hereinafter.

Preparation

According to the invention there is also provided a process for the preparation of compounds of formula I which comprises:

(a) reaction of a compound of formula IV, . R⁴

wherein Ar¹, R\ R², R³, R⁴ and n are as hereinbefore defined, with a compound of formula V,

wherein L¹ represents a leaving group (e.g. OH, OBt, OSu, Hal, nitrophenoxy), Hal represents CI, Br or I, and R⁵ and R⁶ are as hereinbefore defined, for example under peptide coupling conditions known to those skilled in the art (e.g. in the presence of a reaction-inert solvent (e.g. THF, dichloromethane, acetonitrile, DMF or mixtures thereof), optionally in the presence of a suitable base (e.g. triethylamine, diisopropylethylamine, pyridine or K₂C0₃) and, in the case when L¹ represents OH, in the presence of a peptide coupling agent (e.g. DCC, HATU, TBTU, DIC or EDC));

(b) reaction of a compound of formula VI,

wherein L¹, R⁴, R⁵, R⁶ and n are as hereinbefore defined, with a compound of formula VII,

wherein Ar¹, R¹, R² and R³ are as hereinbefore defined, for example under peptide coupling conditions known to those skilled in the art (e.g. as described hereinbefore (process step (a));

(c) conversion of one R^s and/or R^δ substituent to another using techniques well known to those skilled in the art; or

(d) conversion of one substituent on Ar¹ to another using techniques well known to those skilled in the art.

Compounds of formula IV may be prepared by reaction of a compound of formula VIII, ^R4

wherein L² represents a leaving group and R⁴ and n are as hereinbefore defined, with a compound of formula VII, as hereinbefore defined, for example under peptide coupling conditions known to those skilled in the art (e.g. as described hereinbefore for the preparation of compounds of formula I (process step (a)).

Leaving groups that L² may represent include "activating" groups for carboxylic acids that may be employed in the formation of amides (i.e. those that are suitable for use in the acylation of amines). Suitable groups thus include those listed in Comprehensive Organic Chemistry, Eds. Barton and Ollis, Vol. 2, Pergamon Press (1979), especially those listed at pages 636 to 638 and 958-964; Principles of Peptide Synthesis, 2^nd edition, - Bodanszky, Springer-Verlag (1993); and The Peptides, Analysis, Synthesis, Biology, Eds. Gross and Meienhofer, Academic Press (1979), the disclosures in which documents are hereby incorporated by reference.

Thus, suitable leaving groups that L² may represent include OH, OR²⁰, OPy, OSu, OBt, OAt, SH, SR²⁰, SPy, halo, N₃, CN, BF₄, 1-imidazolyl, l-(l,2,4)-triazolyl, 0-(OEt)C=CH₂, 0-CH₂C(0)OR²⁰, OCH₂CN, ON(H)C(0)OR²⁰, ON(H)C(0)R²⁰, ON(R²⁰)₂, ON=C(Ph)₂,

ON=C(CN)C(0)OEt, 0(N(H)(R))C=N-R²⁰, 0(N(H)(Et))C = N-(CH₂)₃- N(Me)₂, OOC-H, OOC-R²⁰, 0₃S-R²⁰, OTs, OOC-N(R²⁰)₂, OOC-OR²⁰, OP(Cl)₂, OP(Cl)OR²⁰, OP(OR²⁰)₂, O-P⁺(R²⁰)₃, 0-P⁺(NMe)₃, OP(=0)(Cl)₂, OP(=O)(R²⁰)₂ and OP(=O)(OR²⁰)₂, in which, in each case, R²⁰ may represent C_1-7 alkyl, aryl (e.g. phenyl or naphthyl) or C alkylaryl (e.g. benzyl), which aryl and alkylaryl groups are optionally substituted by one or more of halo, N0₂, CN and S0₂Me. Alkyl groups that R²⁰ may represent may be linear or branched, saturated or unsaturated and/or cyclic, acyclic or part cyclic/acyclic as described hereinbefore. Compounds of formula VI may be prepared by reaction of a compound of formula VIII in which L² represents OH, or a protected derivative thereof, with a compound of formula V, as hereinbefore defined, for example under peptide coupling conditions known to those skilled in the art (e.g. as described hereinbefore for the preparation of compounds of formula I (process step (a)), followed (if required) by conversion of the OH group of the resultant compound to another group that L¹ may represent under conditions well known to those skilled in the art.

Compounds of formula VI may alternatively be prepared by hydrolytic decarboxylation of a corresponding compound of formula IX,

wherein R^x represents C alkyl and R⁴, R⁵, R^δ and n are as hereinbefore defined, for example under conditions known to those skilled in the art (e.g. at between room and reflux temperature in the presence of a suitable source of the hydroxide ion (e.g. sodium hydroxide or potassium hydroxide) and an appropriate solvent (e.g. water, dioxane, or a mixture thereof)), followed (if required) by conversion of the OH group of the resultant compound to another group that L¹ may represent under conditions well known to those skilled in the art. If desired, a mono-hydrolysed malonate derivative (i.e. a compound equivalent to a compound of formula IX, in which one of the R^x groups is replaced by H) may be isolated following the reaction with hydroxide, and prior to the decarboxylation.

Compounds of formula VIII may be prepared by reaction of a compound of formula X,

wherein R^y represents C alkyl or benzyl and Ph represents phenyl, with a compound of formula XI,

R⁴-(CH₂)_n-L³ XI wherein L³ represents a leaving group (e.g. Hal, alkanesulfonate or arenesulfonate) and R⁴, n and Hal are as hereinbefore defined, for example at between -80 °C and reflux in the presence of a suitable base (e.g. sodium hydride, lithium diisopropylamide or potassium carbonate) and a reaction-inert solvent (e.g. acetonitrile, THF or DMF), followed by removal of the N-diphenylmethylene group under conditions known to those skilled in the art (e.g. by acidic hydrolysis or hydrogenation) as well as conversion of the OR^y group to an L² group (which may take place simultaneously with the removal of the N-diphenylmethylene group) under conditions known to those skilled in the art (e.g. by way of hydrogenation or acidic or basic hydrolysis).

Compounds of formula VIII may alternatively be prepared by hydrolytic decarboxylation of a corresponding compound of formula XII,

wherein R⁴, R^x and n are as hereinbefore defined, for example under conditions as described hereinbefore for the preparation of compounds of formula VI, followed (if required) by conversion of the OH group of the resultant compound to another group that L² may represent under conditions well known to those skilled in the art. As before, a mono-hydrolysed malonate derivative intermediate may be isolated if desired, for example as described hereinafter.

Compounds of formula VIII in which n represents 2 may alternatively be prepared by reduction of a corresponding compound of formula XIII,

wherein the wavy bond indicates optional cis or trans stereochemistry and R⁴, R^x and R^y are as hereinbefore defined, for example under conditions well known to those skilled in the art (e.g. hydrogenation in the presence of a suitable catalyst (e.g. supported palladium) and a reaction-inert solvent (e.g. ethanol, acetic acid or a mixture thereof)), followed by conversion of the OR^y group of the resultant intermediate to an L² group (which conversion may take place simultaneously with the reduction step).

Compounds of formula IX may be prepared by reaction of a compound of formula XIV,

wherein R⁵, R⁶ and R^x are as hereinbefore defmed, with a compound of formula XI, as hereinbefore defined, for example at between room and reflux temperature in the presence of a suitable base (e.g. DBU or K₂C0₃) and a reaction- inert solvent (e.g. acetonitrile or DMF).

Compounds of formula XII may be prepared by reaction of a compound of formula XV,

wherein R^x is as hereinbefore defined, with a compound of formula XI, as hereinbefore defined, for example under conditions described hereinbefore for the preparation of compounds of formula IX.

Compounds of formula XIII may be prepared by reaction of a compound of formula XVI,

wherein R^a and R^z independently represent phenyl or C_1-6 alkyl (in which cases the phosphorous atom carries a positive charge which is countered by an anion (e.g. a halide ion)), or R^a represents oxo and R^z represents C_1-6 alkoxy, and R^y is as hereinbefore defined, with a compound of formula XVII,

R⁴-CHO XVII wherein R⁴ is as hereinbefore defined, for example under conditions that are known to those skilled in the art (e.g. as described in Tetrahedron Lett. 1988, 29, 3361-3364, such as in the presence of a suitable base (e.g. K₂C0₃, NaH, an alkyllithium or DBU) and a reaction-inert solvent (e.g. DMF, DMSO, benzene or dimethyl ether)).

Compounds of formula XIV may be prepared by reaction of a compound of formula V, as hereinbefore defined, with a compound of formula XV, as hereinbefore defined, for example under peptide coupling conditions known to those skilled in the art (e.g. as described hereinbefore for the preparation of compounds of formula I (process step (a))).

Compounds of formulae V, VII, X, XI, XV, XVI and XVII and derivatives thereof, are either commercially available, are known in the literature, or may be obtained either by analogy with the processes described herein, or by conventional synthetic procedures, in accordance with standard techniques, from readily available starting materials using appropriate reagents and reaction conditions.

Substituents on the aryl (e.g. phenyl), and (if appropriate) heterocyclic, group(s) in compounds defined herein may be converted to other substituents using techniques well known to those skilled in the art. For example, amino may be converted to amido, ureidyl or carbamate, alkylamino may be converted to alkylamido, alkylureidyl or alkylcarbamate, amido may be hydrolysed to amino, hydroxy may be converted to alkoxy, acyloxy may be hydrolysed to hydroxy etc.

The skilled person will also appreciate that other various standard substituent or functional group interconversions and transformations within certain compounds of formula I will provide other compounds of formula I.

For example, compounds of formula I in which R⁸ represents -CH₂NH₂ may be converted to corresponding compounds of formula I in which R⁸ represents -CH₂N(H)C(0)N(H)R¹⁶ by reaction with an isocyanate compound of formula R¹⁶NCO, in which R¹⁶ is as hereinbefore defined, and may be converted to corresponding compounds of formula I in which -. R⁸ represents -CH₂N(H)C(0)OR^16a by reaction with a compound of formula R^16aOC(0)Hal, in which R^16a and Hal are as hereinbefore defined, in both cases under conditions that are well known to those skilled in the art.

The compounds of the invention may be isolated from their reaction mixtures using conventional techniques.

It will be appreciated by those skilled in the art that, in the processes described above, the functional groups of intermediate compounds may be, or may need to be, protected by protecting groups.

Protecting groups may also be linked to a polymer (solid support) to enable the use of the compounds/intermediates so obtained in a solid state synthesis and/or combinatorial chemistry experiment.

Functional groups which it is desirable to protect include hydroxy, amino and carboxylic acid. Suitable protecting groups for hydroxy include trialkylsilyl and diarylalkylsilyl groups (e.g. rerr-butyldimethylsilyl, tert- butyldiphenylsilyl or trimethylsilyl), tetrahydropyranyl, benzyl, allyl and alkylcarbonyl groups (e.g. methyl- and ethylcarbonyl groups). Suitable protecting groups for amino include benzyl, trityl, ally loxy carbonyl, tert- butyloxycarbonyl, 9-fluorenylmethoxycarbonyl or benzyloxycarbonyl. Suitable protecting groups for carboxylic acid include C_1-6 alkyl, allyl or benzyl esters.

The protection and deprotection of functional groups may take place before or after any of the reaction steps described hereinbefore.

Protecting groups may be removed in accordance with techniques which are well known to those skilled in the art and as described hereinafter.

The use of protecting groups is fully described in "Protective Groups in Organic Chemistry", edited by JWF McOmie, Plenum Press (1973), and "Protective Groups in Organic Synthesis", 3^rd edition, TW Greene & PGM Wutz, Wiley-Interscience (1999).

Persons skilled in the an will appreciate that, in order to obtain compounds of the invention in an alternative, and, on some occasions, more convenient, manner, the individual process steps mentioned herein may be performed in a different order, and/or the individual reactions may be performed at a different stage in the overall route (i.e. substituents may be added to and/or chemical transformations performed upon, different intermediates to those associated hereinbefore with a particular reaction). This will depend inter alia on factors such as the nature of other functional groups present in a particular substrate, the availability of key intermediates and the protecting group strategy (if any) to be adopted. Clearly, the type of chemistry involved will influence the choice of reagent that is used in the said synthetic steps, the need, and type, of protecting groups that are employed, and the sequence for accomplishing the synthesis.

The above procedures may be adapted as appropriate to the particular reactants and groups involved and other variants will be evident to the skilled chemist by reference to standard textbooks and to the examples provided hereinafter to enable all of the compounds of formula I to be prepared.

It will be appreciated by those skilled in the art that, certain protected derivatives of compounds of formula I, which may be made prior to a final deprotection stage, may not possess pharmacological activity as such, but may, in certain instances, be administered parenterally or orally and thereafter metabolised in the body to form compounds of the invention which are pharmacologically active. Such derivatives may therefore be described as "prodrugs". Further, certain compounds of formula I may act as prodrugs of other compounds of formula I.

All prodrugs of compounds of formula I are included within the scope of the invention.

Medical and pharmaceutical use

The compounds of the invention are useful because they possess pharmacological activity. They are therefore indicated as pharmaceuticals. According to a further aspect of the invention there is thus provided the com tpounds of the invention for use as pharmaceuticals.

In particular, the compounds of the invention are potent antagonists of NPY for example as demonstrated in the tests described below.

The compounds of the invention are thus expected to be useful in the treatment of diseases/disorders which are/may be mediated by NPY, such as cardiovascular diseases.

The compounds of the invention are thus indicated for use in the treatment of coronary heart diseases such as angina pectoris, myocardial infarction and syndrome X as well as high blood pressure, hypertension and chronic heart insufficiency.

According to a further aspect of the invention, there is provided a method of treatment of a cardiovascular disease, which method comprises administration of a therapeutically effective amount of a compound of the invention to a person suffering from, or susceptible to, such a condition.

By the term "treatment", we include both therapeutic (curative) or prophylactic treatment.

The compounds of the invention are also indicated for use in the treatment of other diseases in which NPY is thought to play a pathogenic role, such as chronic kidney failure, tumour diseases such as phaeochromocytoma, infections, migraine and hyperthyroidism, as well as obesity and diabetes. Compounds of the invention have been found to be selective antagonists of the NPY sub-receptor Y_y, for example as demonstrated in the tests described below.

The compounds of the invention thus find particularly utility in the inhibition of vasoconstriction and in disease states characterised thereby such as migraine, Hόrton's syndrome, Raynauld's disease, vasospasm after subarachnoid haemorrhage, angina pectoris, coronary infarction, heart failure, cardiac arrhythmias, hypertension, endotoxin shock and stroke.

According to a further aspect of the invention there is provided a method of treatment of vasoconstriction, which method comprises administration of a therapeutically effective amount of a compound of the invention, or a pharmaceutically acceptable derivative thereof, to a person suffering from, or susceptible to, such a condition.

Pharmaceutical preparations

The compounds of the invention will normally be administered orally, intravenously, subcutaneously, buccally, rectally, dermally, nasally, tracheally, bronchially, by any other parenteral route or via inhalation, in the form of pharmaceutical preparations comprising the active ingredient either as a free base, or a pharmaceutically acceptable non-toxic organic or inorganic acid addition salt, in a pharmaceutically acceptable dosage form. Depending upon the disorder and patient to be treated and the route of administration, the compositions may be administered at varying doses. The compounds of the invention may also be combined with other therapeutic agents which are useful in the treatment of cardiovascular disease, for example β-adrenoceptor antagonists, ACE-inhibitors, diuretics, and calcium antagonists.

The skilled person will also appreciate that compounds of the invention may be taken as a single dose on an "as required" basis (i.e. as needed or desired).

According to a further aspect of the invention there is thus provided a pharmaceutical formulation including a compound of the invention in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier.

Suitable doses of the compounds of the invention in therapeutic treatment of humans are about 0.1-1 mg/kg body weight per day at peroral administration and 0.001-0.1 mg/kg body weight per minute at parenteral administration.

Compounds of the invention may have the advantage that they may be more efficacious, be less toxic, be longer acting, produce fewer side effects, have a broader range of activity, be more potent, be more easily absorbed than, or that they may have other useful pharmacological properties over, compounds known in the prior art.

Biological Tests

Test A

Binding to NPY Yj/Y? Receptors in vitro

(a) Preparation of Receptor Containing Membranes

(i) Y, receptors

The main portion of the rat brain cortex was used for this preparation. The rats (male or female Sprague-Dawley rats, weighing 150-250 g) were killed using C0₂ followed by bleeding. The brains were excised, and put in ice cold buffer (0.3 M sucrose, 5 mM HEPES; pH 7.4).

The material was diluted in 10 volumes of ice cold buffer, cut in smaller pieces, and homogenised first with a polytrone followed by 10 strokes at maximum speed with a Potter-Elvehjem homogeniser.

The homogenate was centrifuged at 650 x g at 4°C for 10 minutes. The supernatant was further centrifuged at 33 000 x g at 4°C for 19 minutes. The pellets were washed once by resolving them in buffer and repeating the last centrifugation step. The final pellets were resolved in a small volume (0.3-1 mL per gram tissue) of buffer complemented with 10% (v/v) glycerol. Aliquots (-200 μL) were quickly frozen in MeOH and dry ice, and stored at -80 °C until further use.

The protein concentration was determined according to Bradford (Anal. Biochem. (1976) 72, 248). The Y_! preparation contained approximately 70-80% Y_t receptors. (ii) Y₂ receptors

This preparation was performed using pig spleen from a local slaughter house (Farmek Ekonomisk, Forening, Varberg, Sweden). The preparative procedure was the same as for the Y receptor above. The resulting membranes contained approximately 80-90% Y₂ receptors.

(b) Receptor Binding Assay

In a typical experiment, 150 μg of Y_L or Y₂ receptor containing membranes was mixed with ³H-NPY and test compound in different concentrations. Membranes and ligands were diluted in the assay buffer (137 mM NaCl, 2.7 mM KC1, 2.1 mM MgCl₂, 1.8 mM CaCl₂, 0.2% (w/v) bovine serum albumin, 20 mM HEPES; pH 7.4). The samples were incubated for 60 minutes at 30 °C, and the binding reaction was stopped by rapid filtration on glass fibre filters using a cell harvester to separate unbound and bound isotope labelled ligand. The radioactivity collected on the filters was determined by liquid scintillation counting.

Non specific binding (non NPY related binding) was estimated in the presence of a high concentration (0.1 μM) of unlabelled NPY. The difference between total binding (in the absence of NPY/test compound) and non specific binding was expressed as specific binding and is used at the maximal response in each experiment.

Test B The Effects of Test Compounds on NPY in Anaesthetised Rats

Male Sprague-Dawley rats (300-450 g) from Charles River UK were used.

The animals were initially anaesthetised with sodium pentobarbitone

70 mg/kg i.p. The anaesthesia was maintained by a continuous infusion in the tail artery (12-20 mg/kg/hour). Body temperature was measured by a rectal probe and maintained by means of a heating pad and a heating lamp at 37.5-38.0°C. The rats were tracheotomised (PE 240) to facilitate spontaneous breathing. Catheters (PE 25) were inserted in the right and left jugular veins for infusions of NPY and test compound. In the tail artery a catheter (PE 25) was inserted for measurement of blood pressure (BP) and for a continuous infusion of anaesthesia. Mean arterial pressure was measured with a transducer (156PC) and heart rate was measured from the pulsating arterial pressure signal with a rate-meter. The left renal artery was dissected free and a small probe was placed around the artery (Transonic™ 0.7 VB42) in order to measure renal blood flow.

All signals were recorded on a paper chart recorder (Grass™ Polygraph) and digitised using a standard PC. The sampling rate was 10 samples per second and the mean value was calculated and stored every 2 seconds. The computer program then calculated changes in mean arterial pressure, heart rate and renal blood flow from control values measured before drug administration.

After completion of the surgical preparation above, and a stabilisation period of 30 minutes, NPY (4 μg/kg) was intravenously administered over 20 seconds at 20 minute intervals to induce cardiovascular effects. After 2 stable readings during NPY administration, test compound was intravenously administered in three increasing doses (5, 50 and 500 nmol/kg/min.) over 20 minutes. At the end of each dosing interval, NPY was injected. A test compound was considered to be active if it attenuated the cardiovascular effect of further NPY treatment in a dose-dependent manner.

The invention is illustrated by way of the following examples. Examples

General

Thin layer chromatography utilised Whatman No. 4420 222 silica gel plates with the following eluant systems:

CHC1₃ : MeOH : cone, ammonium hydroxide (154:36:5) (System A); CHC1₃ : MeOH : cone, ammonium hydroxide (93:7: 1) (System B); ethyl acetate : hexanes (1 : 1) (System C); and

CH₂C1₂ : MeOH : cone, ammonium hydroxide (177:20:3) (System D).

Thin layer chromatography also utilized Whatman No. 4420 222 silica gel plates or Analtech No. 02521 silica gel plates with the following eluent systems:

CHCl₃:EtOH:conc. ammonium hydroxide (93:7:1) (System E); CH₂Cl₂:CHCl₃:MeOH:conc. ammonium hydroxide (75:40:9:1) (System F); and CH₂C1₂: MeOH: cone, ammonium hydroxide (88.5:10:1.5) (System G).

LC-MS was performed using a VG Platform, single quadropole instrument and a VG Quattro II, triple quadropole intsrument both utilizing electrospray ionization.

NMR was carried out on a Bruker AC 300 instrument or a Varian 400 instrument operating at ^lH frequencies of 300 and 400 MHz respectively. Starting materials

Example A tgrr-Butyl 5-(bromomethyl)-2-pyridinylcarbamate

(a) Ethyl 6-aminonicotinate

A suspension of 6-aminonicotinic acid (25.0 g, 181 mmol) in ethanol (190 mL) was treated with SOCl₂ (15 mL, 206 mmol). The mixture was refluxed overnight (10 hours), and more SOCl₂ (16 mL) was added. Reflux was continued for a further 3 days, during which time additional SOCl₂ (10 mL) was added each day. The reaction mixture was cooled to room temperature before ether was added. After 24 hours at -20 °C the mixture was filtered. The crude salt was dissolved in methanol (214 mL) and a solution of NaOH (40.0 g, 23.5 mmol) in methanol (90 mL) was added. The reaction mixture was stirred for 1 hour and THF (270 mL) was added. The reaction mixture was purified by flash filtration (THF/MeOH) and concentrated to give 36.2 g (97%) of the sub-title compound. Η NMR (300 MHz, CDC1₃): δ 1.40 (t, 3H), 4.35 (q, 2H), 4.60 (br s, 2H), 7.05 (m, 1H), 7.15 (m, 1H), 8.15 (m, 1H).

(b) Ethyl 6-[(fgrt-butoxycarbonyl)amino1nicotinate

To ethyl 6-aminonicotinate (36.0 g, 217.0 mmol; from step (a) above) in r-BuOH (308 mL) and acetone (103 mL) was added DMAP (0.53 g, 4.34 mmol) and di-ferf-butyl dicarbonate (72.0 g, 330 mmol). The reaction was stirred at room temperature for 10 hours followed by addition of more di- tτ-butyl dicarbonate (2.60 g). After 10 hours stirring at room temperature, hexane (470 mL) was added. The reaction mixture was cooled (-20 °C) for 2 hours and filtered. The filtrate was washed with hexane : dichloromethane (3: 1). Drying of the filtrate in vacuo allowed the isolation of 40.5 g (70%) of the sub-title compound as a solid. Η NMR (300 MHz, CDC1₃): δ 1.40 (t, 3H), 1.50 (s, 18H), 4.40 (q, 2H), 7.75 (m, 1H), 7.80 (m, 1H), 8.60 (m, 1H).

(c) ferr-Butyl 5-(hydroxymethyl)-2-pyridinylcarbamate

To a stirred solution of ethyl 6-[(rgrr-butoxycarbonyl)amino] nicotinate (3.50 g, 13.1 mmol; from step (b) above) in THF (20 mL) was added LiAlH₄ (0.91 g, 24.0 mmol) in THF (20 mL) over a period of 2 hours. The reaction mixture was stirred for 6 hours, then aqueous NH₄C1 (sat.) was added (carefully) until excess hydride had been neutralised. After filtration and evaporation of the solvent, 2.00 g (68%) of the crude subtitle compound was obtained. Η NMR (300 MHz, CDC1₃): δ 1.52 (s, 9H), 4.62 (s, 2H), 7.68 (d, 1H), 7.98 (d, 1H), 8.19 (br s, 1H), 8.29 (s, 1H).

(d) fgrr-Butyl 5-(bromomethyl)-2-pyridinylcarbamate

To a stirred suspension of rr-butyl 5-(hydroxymethyl)-2- pyridinylcarbamate (7.00 g, 31.2 mmol; from step (c) above) in CH₂C1₂ (200 mL) was added triphenylphosphine (8.70 g, 33.1 mmol) and carbon tetrabromide (17.0 g, 51.2 mmol) at room temperature. Stirring was continued for 5 hours followed by evaporation of the solvent. Acetonitrile (200 mL) was added and the mixture was cooled (-20 °C) for 2 hours. The mixture was then filtered and the crystalline residue washed with cold acetonitrile (2 x 10 mL). The title compound (5.96 g, 67%) was obtained as white crystals.

Η NMR (300 MHz, CDC1₃): δ 1.54 (s, 9H), 4.41 (s, 2H), 7.68 (d, 1H), 7.98 (d, 1H), 8.32 (s, 1H), 9.00 (br s, 1H). Example B tgrf-Butyl 4-formyl-2-pyridinylcarbamate

(a) N-(4-Methyl-2-pyridinyl)acetamide A mixture of 2-amino-4-methylpyridine (99.0 g, 91.5 mmol) and acetic anhydride (250 mL) was warmed to 70 °C for two hours. The mixture was cooled to room temperature and 100 mL ether added. The product crystallised as white needles. Filtering and drying in vacuo afforded 130 g (95%) of the sub-title compound. Η NMR (300 MHz, CDC1₃): δ 2.20 (s, 3H), 3.30 (s, 3H), 6.85 (m, 1H), 8.05 (m, 1H), 8.10 (m, 1H), 9.30 (br s, 1H).

(b) 2-(Acetylamino)isonicotinic acid

A mixture of N-(4-methyl-2-pyridyl)acetamide (40.0 g, 0.26 mol; from step (a) above) and water (400 mL) was heated at 90 °C until the solution was homogeneous. Potassium permanganate (100 g, 0.62 mol) was added carefully in small portions with good mechanical stirring over 2 hours. The reaction mixture was kept at 90-95 °C for a further 3 hours before filtering through Celite^® whilst still hot. The filtrate was concentrated to about 100 mL and concentrated HCl was added to adjust the pH to about 4. The reaction flask was cooled in an ice bath and the white solid filtered off. The crystals were washed with cold water and chloroform and dried in vacuo to give 12.0 g (25%) of the sub-title compound. Η ΝMR (300 MHz, CD₃OD): δ 2.10 (s, 3H), 7.60 (m, 2H), 8.40 (m, 1H), 8.65 (m, 1H).

(c) Ethyl 2-aminoisonicotinate

A suspension of 2-(acetylamino)isomcotinic acid (10.8 g, 60.0 mmol; • from step (b) above) in ethanol (150 mL) was treated with BF₃ OEt₂ (22 mL, 138 mmol). The mixture was refluxed overnight, and after cooling to room temperature 10% NaHC0₃ (250 mL) was added. The product was extracted with chloroform (3 x 100 mL), the combined organic extracts washed with water (250 mL) and dried (MgS0₄). Filtering and concentration afforded 7.46 g (79%) of the sub-title compound as pale yellow crystals.

Η NMR (300 MHz, CDC1₃): δ 1.40 (t, 3H), 4.35 (q, 2H), 4.60 (br s, 2H), 7.05 (m, 1H), 7.15 (m, 1H), 8.15 (m, 1H).

(d) Ethyl 2-fbis(rgrr-butoxycarbonyl)amino]isonicotinate

To ethyl 2-aminoisonicotinate (5.00 g, 30 mmol; from example (c) above) in r-BuOH (45 mL) and acetone (15 mL) was added DMAP (50 mg, 0.41 mmol) and di-fgrr-butyl dicarbonate (16.4 g, 75.0 mmol). The reaction mixture was stirred at room temperature overnight before hexane (60 mL) was added. The mixture was cooled in a refrigerator for 3 hours and the product removed by filtration. Drying in vacuo allowed the isolation of 8.71 g (79%) of the sub-title compound as a light grey solid. Η NMR (300 MHz, CDC1₃): δ 1.40 (t, 3H), 1.50 (s, 18H), 4.40 (q, 2H), 7.75 (m, 1H), 7.80 (m, 1H), 8.60 (m, 1H).

(e) fgrr-Butyl 4-(hydroxymethyl)-2-pyridinylcarbamate Ethyl 2-[bis(tgrr-butoxycarbonyl)amino]isonicotinate (35.0 g, 95.5 mmol; from example (d) above) in THF (350 mL) was treated with LiAlH₄ (7.25 g, 191 mmol) and refluxed for 1 hour under nitrogen. The reaction mixture was poured carefully onto crushed ice and the product extracted several times with CHC1₃ and CHC1₃ : MeOH (90: 10). The combined organic extracts were dried (MgS0₄), filtered and concentrated in vacuo. The sub-title compound (18.5 g, 86%) was thereby isolated as a pale yellow solid, which was shown to be pure by ^lH NMR analysis. Η NMR (300 MHz, CDC1₃): δ 1.50 (s, 9H), 4.60 (s, 2H), 7.00 (m, 1H), 7.90 (m, 1H), 8.25 (m, 1H), 8.60 (br s, 1H).

(f) rg/7-Butyl 4-formyl-2-pyridinylcarbamate fgrf-Butyl 4-(hydroxymethyl)-2-pyridinylcarbamate (1.91 g, 8.51 mmol, from step (e) above) was dissolved in dry DMSO (10 mL) and the reaction flask immersed in a water bath at 15 °C. Trie thy lamine (1.72 g, 17.0 mmol) was added, followed by sulfur trioxide pyridine complex (2.41 g, 15.1 mmol). The reaction mixture was stirred for a further 2 hours and poured onto crushed ice. The product was extracted with CHC1₃ (3 x 30 mL). The combined organic extracts were washed with water (3 x 50 mL), dried (MgS0₄) and filtered. Removal of the solvent and subsequent flash chromatography (hexane : EtOAc (80:20)) afforded 1.57 g (83%) of the title compound as white crystals. Η NMR (300 MHz, CDC1₃): δ 1.58 (s, 9H), 7.40 (d, 1H), 8.30 (br s, 1H), 8.42 (m, 1H), 8.46 (m, 1H), 10.05 (s, 1H).

Example C fgrf-Butyl 5-formyl-2-pyridinylcarbamate fgrr-Butyl 5-(hydroxymethyl)-2-pyridinylcarbamate (7.00 g, 31.2 mmol; from Example A step (c) above) was dissolved in dry DMSO (50 mL) and the reaction flask immersed in a water bath at 15 °C. Triethy lamine (13.1 mL, 94.0 mmol) was added, followed by sulfur trioxide pyridine complex (15.0 g, 94.0 mmol) in portions. The reaction mixture was stirred for a further 45 minutes and poured onto crushed ice (300 mL). The product was extracted with ether (4 x 300 mL). The combined organic extracts were washed with aqueous NaCl (sat.), dried (MgS0₄) and filtered. Removal of the solvent and recrystallisation from hexane/CH₂Cl₂ afforded 5.40 g (78%) of the title compound as white crystals.

Η NMR (300 MHz, CDC1₃): δ 1.58 (s, 9H), 8.20 (s, 2H), 8.82 (s, 1H),

9.02 (br s, 1H), 9.98 (s, 1H).

Example 1

3-(6-Amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-hydroxy- benzyl)propanamide

(a) Diethyl 2-f(2 ,2-diphenylacetyl)aminolmalonate

A mixture of diethyl aminomalonate hydrochloride (5.0 g, 23 mmol) and diisopropylethy lamine (10.3 mL, 59 mmol) in dichloromethane (100 mL) was cooled to 0°C. Solid diphenylacetyl chloride (5.4 g, 23 mmol) was added and the mixture was stirred for 1 h before being warmed to rt and quenched with water. The reaction mixture was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and evaporated to provide the sub-title compound (8.72 g, 96%) as a white solid. Η ΝMR (300 MHz, CDC1₃): δ 7.40-7.23 (m, 10H), 6.63 (d, 1H), 5.18 (d, 1H), 5.03 (s, 1H), 4.33-4.17 (m, 4H), 1.29 (t, 6H).

(b) Diethyl 2-({6-[(rgrf-butoxycarbonyl)amino]-3-pyridinyUmethyl)-2- r(2,2-diphenylacetyl)amino^"lmalonate

A mixture of diethyl 2-[(2,2-diphenylacetyl)amino]malonate (1.6 g, 4.3 mmol; from step (a) above) and fgrr-butyl 5-(bromomethyl)-2- pyridinylcarbamate (1.6 g, 5.5 mmol; from Example A above) in acetonitrile (65 mL) was treated with DBU (1.9 mL, 12 mmol) and the resulting mixture stirred for 3 h. The acetonitrile was removed and the residue was taken up in ethyl acetate. This solution was washed with dilute KHS0₄ solution and then brine, dried (sodium sulfate), filtered and then concentrated in vacuo to provide the sub-title compound (2.4 g,

95%).

Η NMR (300 MHz, CDC1₃): δ 8.13 (br s, 1H), 7.79-7.72 (m, 2H), 7.39-

7.24 (m, 10H), 7.08 (dd, 1H), 6.81 (s, 1H), 4.94 (s, 1H), 4.30-4.19 (m, 4H), 3.58 (s, 2H), 1.56 (s, 9H), 1.30-1.22 (m, 6H).

(c) 3-{6-r(rgrr-Butoxycarbonyl)aminol-3-pyridinyl)-N-(2,2-diphenylacetyl)- alanine

A solution of diethyl 2-({6-[(rgrr-butoxycarbonyl)amino]-3-pyridinyl}- methyl)-2-[(2,2-diphenylacetyl)amino]malonate (2.4 g, 4.1 mmol; from step (b) above) in dioxane : water (132 mL of 5: 1) was treated with potassium hydroxide (4.6 g, 82 mmol) and then heated to reflux for 1 h.

The dioxane was removed and the residue was taken up in ethyl acetate.

This solution was washed with KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo to provide the sub-title compound

(1.7 g, 88%).

Η ΝMR (300 MHz, CDC1₃): δ 9.75 (br s, 1H), 7.86-7.77 (m, 2H), 7.40-

7.25 (m, 10H) 7.18 (dd, 1H), 6.55 (d, 1H), 4.98 (s, 1H), 4.81 (m, 1H), 3.21-3.10 (m, 2H), 1.53 (s, 9H).

(d) fgrf-Butyl 5-{2-[(2,2-diphenylacetyl)amino]-3-[(4-hydroxybenzyl)- aminol-3-oxopropyl}-2-pyridinylcarbamate

A mixture of 3-{6-[(rgrf-butoxycarbonyl)amino]-3-pyridinyl}-N-(2,2- diphenylacetyl)alanine (435 mg, 0.9 mmol; from step (c) above) and l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (192 mg, 1.0 mmol) in tetrahydrofuran : dichloromethane : acetonitrile (45 mL of 4:2:3) was stirred for 10 min before 4-hydroxybenzylamine (123 mg, 1.0 mmol) and diisopropylethylamine (159 μL, 0.9 mmol) were added. The mixture was stirred overnight at rt, the solvents were removed and the residue taken up in ethyl acetate/tetrahydrofuran. This solution was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo. Chromatography on silica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (186: 14: 1), provided the sub-title compound (234 mg, 44%). R_f 0.5 (System B)

(e) 3 -(6- Amino-3 -pyridinyl)-2- [(2 , 2-dipheny lacety l)amino] -N-(4-hydroxy- benzyl)propanamide fgrr-Butyl 5-{2-[(2,2-diphenylacetyl)amino]-3-[(4-hydroxybenzyl)amino]-

3-oxopropyl}-2-pyridinylcarbamate (234 mg, 0.4 mmol; from step (d) above) was dissolved in trifluoroacetic acid/dichloromethane (15 mL of -

2: 1) and stirred for 2 h. Evaporation of the solvent followed by column chromatography on silica gel, eluting with chloroform : ethanol : cone. ammonium hydroxide (186: 14:1), provided the title compound (140 mg,

72%) as a white solid. m.p. 229-230°C

R_f 0.6 (System A)

Η NMR (300 MHz, CD₃OD): δ 7.69 (s, IH), 7.31-7.17 (m, 9H), 7.12- 7.06 (m, 2H), 6.98 (d, 2H), 6.71 (d, 2H), 6.44 (d, IH), 5.00 (s, IH),

4.62 (m, IH), 4.28-4.15 (m, 2H), 2.93 (m, IH), 2.74 (m, IH).

Preparative chiral chromatography was performed on a Chiralpak™ AD column to separate the enantiomers of the tide compound. The racemate (from step (e) above), dissolved in methanol containing 2% acetic acid (7 mg/mL), was injected onto the column (250 x 20 mm ID) and the pure enantiomers were collected and evaporated to dryness. The total amount of racemate that was resolved was 14 mg. The yield for the two enantiomers was 6.5 mg each, with an enantiomeric excess of > 99% , as determined on an analytical scale Chiralpak™ AD column (250 x 4.6 mm ID).

Preparative chromatography was performed on a Gilson gradient HPLC system (mod. 306, Villiers-le-Bel, France) with a dynamic mixer (mod. 811C) and a Gilson (mod. 231 XL) automatic injector equipped with a 10 mL injection loop. The pure enantiomers were collected using a Gilson fraction collector (mod. 206). The flow rate of the mobile phase was 10 mL/min. The analytical HPLC-system comprised a Gynkotek Pump, Model 380 (Germering, Germany), a Kontron 465 Auto Sampler (Milano, Italy) and a JASCO variable wavelength UV-975 Detector (Tokyo, Japan). The chromatographic data was collected using Chromeleon (version 4.3, Dionex, Germering, Germany). The flow rate of the mobile phase was 1.0 mL/min. The mobile phase used for both analytical and preparative scale chromatography consisted of 70% iso-hexaae and 30% tsø-propanol (HPLC grade).

Example 2

3-(6-Anιmo-3-pyridmyl)-2-[(2,2-diphenylacetyl)an inol-N-(4-methoxy- benzyl)propanamide

(a) rgrr-Butyl 5-{2-f(2,2-diphenylacetyl)aminol-3-[(4-methoxybenzyl)- amino]-3-oxopropyl}-2-pyridinylcarbamate

A mixture of 3-{6-[(rgrr-butoxycarbonyl)amino]-3-pyridinyl}-N-(2,2- diphenylacetyl)alanine (1.2 g, 2.5 mmol; from Example 1 step (c) above) and l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (0.55 g, 2.8 mmol) in tetrahydrofuran : dichloromethane : acetonitrile (65 mL of 7:2:4) was stirred for 10 min before 4-methoxybenzy lamine (0.34 mL, 2.6 mmol) was added. The mixture was stirred overnight before the solvents were removed and the residue taken up in ethyl acetate/methanol. This solution was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and evaporated. Chromatography on silica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (186:14: 1), provided the sub-title compound (700 mg, 45 %). m.p. 180-188°C R_f 0.6 (System B)

Η NMR (300 MHz, CD₃OD): δ 7.95 (d, IH), 7.67 (d, IH), 7.48 (dd, IH), 7.30-7.18 (m, 8H), 7.12-7.08 (m, 2H), 7.03 (d, 2H), 6.69 (d, 2H), 4.99 (s, IH), 4.69 (m, IH), 4.23 (dd, 2H), 3.77 (s, 3H), 3.02 (m, IH), 2.85(m, IH), 1.58 (s, 9H).

(b) 3-(6-Amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-methoxy- benzyl)propanamide rgrr-Butyl 5-{2-[(2,2-diphenylacetyl)amino]-3-[(4-methoxybenzyl)amino]-

3-oxopropyl}-2-pyridinylcarbamate (700 mg, 1.1 mmol; from step (a) above) was dissolved in trifluoroacetic acid : dichloromethane (60 mL of

2: 1) and stirred for 114 h. Evaporation of the solvent, followed by column chromatography on silica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (186: 14:1), provided the title compound

(502 mg, 71 %) as a white solid. m.p. 211-212°C

R_f 0.3 (System B)

Η ΝMR (300 MHz, CD₃OD): δ 7.69 (d, IH), 7.30-7.18 (m, 9H), 7.13- 7.09 (m, 2H), 7.05 (d, 2H), 6.82 (d, 2H), 6.44 (d, IH), 5.00 (s, IH),

4.62 (m, IH), 4.25 (dd, 2H), 3.78 (s, 3H), 2.93 (m, IH), 2.75 (m, IH). Example 3

4-(2-Amino-4-pyridinyl)-2-f(2,2-diphenylacetyl)amino1-N-(4-hydroxy- benzyl)butanamide

(a) Ethyl 4-{2-[(tgrr-butoxycarbonyl)amino1-4-pyridinyl}-2-(methoxy- imino)-3-butenoate

To a stirred solution of [(2-methoxyimino-2-ethoxycarbonyl)ethyl]- triphenylphosphonium bromide (Tetrahedron Lett. 1988, 29, 3361-3364; 4.3 g, 8.9 mmol) in dimethylformamide (40 mL) was added potassium carbonate (2.6 g, 18 mmol) and rgrf-butyl 4-formyl-2 -pyridinylcarbamate (2.0 g, 8.9 mmol; from Example B above). After 6 h the dimethylformamide was removed and the residue was taken up in - dichloromethane. This solution was washed with water, dried (sodium sulfate), filtered and evaporated. Chromatography on silica gel eluting with ethyl acetate : hexane (1:3) provided the sub-title compound (2.8 g, 91 %).

R_f 0.5 (System C)

Η ΝMR (300 MHz, CDC1₃): δ 8.23 (d, IH), 8.03 (s, IH), 7.56 (d, IH), 7.59 (s, IH), 7.34 (d, IH), 7.10 (d, IH), 4.40 (q, 2H), 4.16 (s, 3H), 1.56 (s, 9H), 1.40 (t, 3H).

(b) Ethyl 2-amino-4-{2-f(rgrt-butoxycarbonyl)amino1-4-pyridinyl}- butanoate

Ethyl 4-{2-[(rgrr-butoxycarbonyl)amino]-4-pyridinyl}-2-(methoxyimino)-3- butenoate (2.8 g, 8.0 mmol; from step (a) above) was dissolved in ethyl acetate : ethanol (250 mL of 1: 1) by warming gently under an inert atmosphere (Ν₂). Palladium on carbon (200 mg of 10%) was added, and the flask evacuated then filled with hydrogen from a balloon. After stirring for 3 h, the catalyst was removed via filtration and the solvent was evaporated. The residue was purified by column chromatography on sdica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (186:14: 1), to provide the sub-title compound (2.2 g, 83%). R_f 0.5 (System B) ^lU NMR (300 MHz, CDC1₃): δ 8.15 (d, IH), 7.82 (s, IH), 7.71 (br s, IH), 6.83 (d, 2H), 4.20 (q, 2H), 3.43 (m, IH), 2.65-2.85 (m, 2H), 2.08 (m, IH), 1.87 (m, IH), 1.51 (s, 11H), 1.28 (t, 3H).

(c) Ethyl 4-{2-r(rgrr-butoxycarbonyl)aminol-4-pyridinyl}-2-r(2,2-diphenyl- acetyl)amino]butanoate

A mixture of ethyl 2-amino-4-{2-[(rgrr-butoxycarbonyl)amino]-4- pyridinyl}butanoate (2.2 g, 6.8 mmol; from step (b) above) and - diisopropylethy lamine (1.4 mL, 8.2 mmol) in dichloromethane (40 mL) was cooled to 0°C. Solid diphenylacetyl chloride (1.5 g, 6.8 mmol) was added, and the mixture was stirred for 1 h before being warmed to rt and quenched with water. The reaction mixture was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo to provide the sub-tide compound (3.1 g, 88%). R_f 0.7 (ethyl acetate) Η NMR (300 MHz, CDC1₃): δ 8.10 (d, IH), 7.90 (s, IH), 7.77 (s, IH), 7.40-7.21 (m, 10H), 6.69 (d, IH), 6.18 (d, IH), 4.99 (s, IH), 4.69 (m, IH), 4.18 (q, 2H), 2.62-2.45 (m, 2H), 2.20 (m, IH), 1.96 (m, IH), 1.54 (s, 9H), 1.28 (t, 3H).

(d) 4-{2-[(rgrf-Butoxycarbonyl)amino]-4-pyridinyU-2-[(2,2-diphenyl- acetyl)amino]butanoic acid

A solution of ethyl 4-{2-[(rgrr-butoxycarbonyl)amino]-4-pyridinyl}-2- [(2,2-diphenylacetyl)amino]butanoate (3.1 g, 6.0 mmol; from step (c) above) in dioxane : water (120 mL of 5: 1) was treated with potassium hydroxide (3.3 g, 59 mmol). The mixture was heated to reflux for 1 h before the dioxane was removed and the residue taken up in ethyl acetate.

This solution was washed with KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo to provide the sub-title compound (2.9 g, 98%).

Η NMR (300 MHz, CDC1₃): δ 9.91 (br s, IH), 7.92 (s, IH), 7.58 (d, IH), 7.40-7.22 (m, 10H), 6.71-6.63 (m, 2H), 5.05 (s, IH), 4.60 (m, IH), 2.70 (m, IH), 2.58-2.42 (m, 2H), 2.29 (m, IH), 2.54 (s, 9H).

(e) fgrr-Butyl 4-{3-r(2,2-diphenylacetyl)amino1-4-f(4-hydroxybenzyl)- aminol -4-oxobuty 1} -2-pyridiny lcarbamate

A solution of 4-{2-[(rgrf-butoxycarbonyl)amino]-4-pyridinyl}-2-[(2,2^ _r diphenylacetyl)amino]butanoic acid (500 mg, 1.0 mmol; from step (d) above) and l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (215 mg, 1.1 mmol) in tetrahydrofuran : dichloromethane : acetonitrile (26 mL of 6:2:5) was stirred for 10 min before 4-hydroxybenzylamine (126 mg, 1.0 mmol) was added. The mixture was stirred overnight, the solvents were removed and the residue was taken up in ethyl acetate. This solution was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo. Chromatography on silica gel eluting, with chloroform : ethanol : cone, ammonium hydroxide (186:14: 1) provided the sub-title compound (394 mg, 65%). R_f 0.5 (System B)

(f) 4-(2-Amino-4-pyridinyl)-2-r(2,2-diphenylacetyl)aminol-N-(4-hydroxy- benzyl)butanamide rg/τ-Butyl 4-{3-[(2,2-diphenylacetyl)amino]-4-[(4-hydroxybenzyl)amino]-

4-oxobutyl}-2-pyridinylcarbamate (394 mg, 0.6 mmol; from step (e) above) was dissolved in trifluoroacetic acid : dichloromethane (15 mL of 2: 1) and stirred for 1 h. Evaporation of the solvent followed by column chromatography on silica gel, eluting with chloroform : methanol : cone, ammonium hydroxide (177:20:3), provided the title compound (295 mg, 90%) as a white solid, m.p. 95-100°C R_f 0.4 (System D) ^lH NMR (300 MHz, CD₃OD): δ 7.71 (d, IH), 7.37-7.21 (m, 10H), 7.08 (d, 2H), 6.72 (d, 2H), 6.32-6.28 (m, 2H), 5.09 (s, IH), 4.36 (m, IH), 4.30-4.19 (m, 2H), 2.51-2.32 (m, 2H), 2.03 (m, IH), 1.94 (m, IH).

Example 4

4-(2-Amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino1-N-(4- methoxybenzyl)butanamide

(a) t grr-Butyl 4- { 3 -f(2 , 2-dipheny lacet l)amino1 -4- [(4-methoxybenzy 1)- aminol-4-oxobutyl}-2-pyridinylcarbamate

A solution of 4-{2-[(rg/ -butoxycarbonyl)amino]-4-pyridinyl}-2-[(2,2- diphenylacetyl)amino]butanoic acid (1.5 g, 3.0 mmol; from Example 3 step (d) above) and l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (0.64 g, 3.3 mmol) in tetrahydrofuran : dichloromethane (45 mL of 7:2) was stirred for 5 minutes before 4-methoxybenzy lamine (0.4 mL, 3.0 mmol) was added. The mixture was stirred for 3 h before the solvents were removed and the residue taken up in ethyl acetate. This solution was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo. Chromatography on silica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (465:20:2), provided the sub-title compound (1.17 g, 63 %). m.p. 192-197°C R_f 0.6 (System B)

Η NMR (300 MHz, CD₃OD): δ 8.02 (d, IH), 7.69 (s, IH), 7.34-7.20 (m, 10H), 7.16 (d, 2H), 6.83 (d, 2H), 6.70 (d, IH), 5.09 (s, IH), 4.39 (m, IH), 4.32-4.22 (m, 2H), 3.78 (s, 3H), 2.63-2.47 (m, 2H), 2.19 (m, IH), 1.98 (m, IH), 1.53 (s, 9H).

(b) 4-(2-Amino-4-pyridinyl)-2-r(2,2-diphenylacetyl)aminol-N-(4-methoxy- benzyl)butanamide rgrr-Butyl 4-{3-[(2,2-diphenylacetyl)amino]-4-[(4-methoxybenzyl)amino]- 4-oxobutyl}-2-pyridinylcarbamate (1.0 g, 1.6 mmol; from step (a) above) was dissolved in trifluoroacetic acid : dichloromethane (45 mL of 2: 1) and stirred for 2 h. Evaporation of the solvent followed by column - chromatography on silica gel, eluting with chloroform : methanol : cone. ammonium hydroxide (186: 14: 1), provided the title compound (425 mg, 47%) as a white solid. m.p. 184-187°C

R_f 0.4 (System B)

Η ΝMR (300 MHz, CD₃OD): δ 7.71 (d, IH), 7.37-7.21 (m, 10H), 7.16

(d, 2H), 6.82 (d, 2H), 6.32-6.28 (m, 2H), 5.09 (s, IH), 4.37 (m, IH), 4.33-4.22 (m. 2H), 3.77 (s, 3H), 2.51-2.33 (m, 2H), 2.02 (m, IH), 1.93

(m, IH).

Example 5

4-(6-Amino-3-pyridinyl)-2-[(2,2-diphenyIacetyl)amino]-N-(4-methoxy- benzyl)butanamide

(a) Ethyl 4- { 6- [^"(tgtf-butoxy carbony l)amino] -3-pyridiny 1 } -2-(methoxy- imino)-3-butenoate

To a stirred solution of [(2-methoxyimino-2-ethoxycarbonyl)ethyl]- triphenylphosphonium bromide (Tetrahedron Lett. 1988, 29, 3361-3364; 4.3 g, 8.9 mmol) in dimethylformamide (40 mL) was added potassium carbonate (2.6 g, 18 mmol) and fgrϊ-butyl 5-formyl-2-pyridinylcarbamate (2.0 g, 8.9 mmol; from Example C above). After 6 h the dimethylformamide was removed and the residue taken up in - dichloromethane. This solution was washed with water, dried (sodium sulfate), filtered and concentrated in vacuo. Chromatography on silica gel, eluting with ethyl acetate : hexane (1:3), provided the sub-title compound (2.8 g, 91 %).

Η ΝMR (300 MHz, CDC1₃): δ 8.38 (d, IH), 8.08 (s, IH), 8.00 (dd, IH), 7.88 (dd, IH), 7.56 (d, IH), 7.15 (d, IH), 4.40 (q, 2H), 4.15 (s, 3H), 1.55 (s, 9H), 1.41 (t, 3H).

(b) Ethyl 2-amino-4-{6-r(rgrr-butoxycarbonyl)amino1-3-pyridinyU- butanoate

Ethyl 4-{6-[(rgrr-butoxycarbonyl)amino]-3-pyridinyl}-2-(methoxyimino)-3- butenoate (2.8 g, 8.0 mmol; from step (a) above) was dissolved in ethyl acetate : ethanol (200 mL of 5:3) by warming gendy under an inert atmosphere (Ν₂). Palladium on carbon (200 mg of 10%) was added and the flask was evacuated then filled with hydrogen from a balloon. After stirring for 7 h, the catalyst was removed via filtration and the solvent was evaporated. The residue was purified by column chromatography on silica gel, eluting with chloroform : ethanol : cone, ammonium hydroxide (186:14: 1) to provide the sub-title compound (1.7 g, 66%). Η NMR (300 MHz, CD₃OD): δ 8.09 (d, IH), 7.78 (d, IH), 7.62 (dd, IH), 4.17 (q, 2H), 3.42 (m, IH), 2.68 (t, 2H), 2.00 (m, IH), 1.89 (m, IH), 1.53 (s, 9H), 1.29 (t, 3H).

(c) Ethyl 4-{6-[(tgrr-butoxycarbonyl)aminol-3-pyridinyl)-2-[(2,2-diphenyl- acety l)amino] butanoate

A mixture of ethyl 2-amino-4-{6-[(fgrr-butoxycarbonyl)amino]-3- pyridinyl}butanoate (1.7 g, 5.2 mmol; from step (b) above) and diisopropylethy lamine (1.1 mL, 6.3 mmol) in dichloromethane (30 mL) was cooled to 0°C. Solid diphenylacetyl chloride (1.2 g, 5.2 mmol) was - added and the mixture was stirred for 1 h before being warmed to rt.

Stirring was continued overnight before the reaction mixture was quenched with water, washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and concentrated in vacuo to provide the sub-tide compound (2.6 g, 95%).

Η NMR (300 MHz, CDC1₃): δ 7.96 (d, IH), 7.83 (d, IH), 7.54 (br s,

IH), 7.40-7.22 (m, 11H), 6.20 (d, IH), 4.98 (s, IH), 4.68 (m, IH), 4.17 (q, 2H), 2.57-2.38 (m, 2H), 2.14 (m, IH), 1.90 (m, IH), 1.53 (s, 9H),

1.28 (t, 3H).

(d) 4-{6-r(rgrr-Butoxycarbonyl)aminol-3-pyridinyl}-2-[(2,2-diphenyl- acetyl)amino]butanoic acid A solution of ethyl 4-{6-[(rgrr-butoxycarbonyl)amino]-3-pyridinyl}-2- [(2,2-diphenylacetyl)amino]butanoate (2.5 g, 4.8 mmol; from step (c) above) in dioxane : water (120 mL of 5: 1) was treated with potassium hydroxide (2.7 g, 48 mmol). The mixture was then heated to reflux for 45 minutes before the dioxane was removed and the residue taken up in ethyl acetate. Water and dilute KHS0₄ solution were added, causing the product to precipitate out of solution. Collection of the solid by filtration provided the sub-title compound (1.6 g, 66%) as a white solid. Η NMR (300 MHz, CDC1₃): δ 9.69 (s, IH), 7.87 (d, IH), 7.63 (s, IH), 7.45-7.29 (m, 10H), 7.02 (br s, IH), 6.50 (d, IH), 5.09 (s, IH), 4.58 (m, IH), 2.75-2.55 (m, 2H), 2.42-2.29 (m, 2H), 1.53 (s, 9H).

(e) rgrf-Butyl 5-{3-[(2,2-diphenylacetyl)amino]-4-[(4-methoxybenzyl)- amino^"l-4-oxobutyl}-2-pyridinylcarbamate A mixture of 4-{6-[(rgrr-butoxycarbonyl)amino]-3-pyridinyl}-2-[(2,2- diphenylacetyl)amino]butanoic acid (1.5 g, 3.0 mmol; from step (d) above) and l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide - hydrochloride (0.68 g, 3.5 mmol) in tetrahydrofuran : dichloromethane (60 mL of 7:5) was stirred for 10 min before 4-methoxybenzylamine (0.4 mL, 3.0 mmol) was added. The mixture was stirred for 4 h before the solvents were removed and the residue taken up in ethyl acetate. This solution was washed with dilute KHS0₄ solution, dried (sodium sulfate), filtered and partially concentrated until the product crystallised out of solution. Collection of the solids by filtration provided the sub-title compound (0.9 g , 48 % ) . m.p. 180-183°C R_f 0.5 (System B)

Η NMR (300 MHz, CD₃OD): δ 7.91 (d, IH), 7.70 (d, IH), 7.40 (dd, IH), 7.38-7.20 (m, 10H), 7.16 (d, 2H), 6.82 (d, 2H), 5.09 (s, IH), 4.39- 4.20 (m, 3H), 3.78 (s, 3H), 2.60-2.40 (m, 2H), 2.10-1.86 (m, 2H). (f) 4-(6-Amino-3-pyridinyl)-2-r(2,2-diphenylacetyl)aminoi-N-(4-methoxy- benzyl)butanamide rgrr-Butyl 5-{3-[(2,2-diphenylacetyl)amino]-4-[(4-methoxybenzyl)amino]- 4-oxobutyl}-2-pyridinylcarbamate (0.9 g, 1.5 mmol; from step (e) above) was dissolved in trifluoroacetic acid : dichloromethane (45 mL of 2:1) and stirred for 2 h. Evaporation of the solvent followed by column chromatography on silica gel, eluting with chloroform : methanol : cone, ammonium hydroxide (186: 14: 1), provided the title compound (631 mg, 82%) as a white solid. m.p. 176-178°C R_f 0.3 (System B)

Η NMR (300 MHz, CD₃OD): δ 7.49 (d, IH), 7.39-7.11 (m, 13H), 6.82 - (d, 2H), 6.48 (d, IH), 5.10 (s, IH), 4.38-4.21 (m, 3H), 3.78 (s, 3H), 2.49-2.29 (m 2H), 2.04-1.80 (m, 2H).

Example 6

3-(6-Amino-3-pyridinyl)-2-f(2,2-diρhenylacetyl)amino1-N-(4-methoxy- benzyl)-N-methylpropanamide

(a) fgA7-Butyl 5-{2-r(2,2-diphenylacetyl)aminol-3-r(4-methoxybenzyl)- (methyl)aminol-3-oxopropyl}-2-pyridinylcarbamate 3-{6-[(fgrr-Butoxycarbonyl)amino]-3-pyridinyl}-N-(2,2-diphenylacetyl)- alanine (300 mg; 0.6 mmol; see Example 1(c) above) and l-[3- (dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (192 mg; 0.6 mmol) were dissolved in tetrahydrofuran:dichloromethane:acetonitrile (8 mL:2.5 mL: 10 mL) and stirred for 10 min. before N-methyl-4- methoxybenzylamine (123 mg; 1.0 mmol) was added. The mixture was stirred 48 h at rt, the solvents were removed and the residue was taken up in ethyl acetate, washed with dilute KHS0₄ soln. , dried with sodium sulfate, filtered and evaporated. Chromatography on silica gel eluting with 93:7:0.5 chloroform: ethanol: cone, ammonium hydroxide provided the sub-title compound (302 mg; 78%).

Η NMR (300 MHz, CD₃OD): δ 7.75 and 7.62 (d, IH), 7.25 (m, 9H), 7.12 and 7.08 (m, 2H), 6.99 (d, 2H), 6.81 (m, 2H), 6.46 and 6.41 (d, IH), 5.13 (m, IH), 5.01 and 4.98 (s, IH), 4.62-4.37 (m, 2H), 3.76 (s, 3H), 2.98-2.68 (m, 2H), 2.89 and 2.85 (s, 3H)

(b) 3-(6-Amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino1-N-(4-methoxy- benzyl)-N-methylpropanamide rgrr-Butyl 5-{2-[(2,2-diphenylacetyl)amino]-3-[(4-methoxybenzyl)(methyl)- amino]-3-oxopropyl}-2-pyridinylcarbamate (302 mg; 0.5 mmol; from step - (a) above) was dissolved in trifluoroacetic acid: dichloromethane (6 mL:5 mL) and was stirred for 3.75 h. Evaporation of the solvent followed by column chromatography on silica gel eluting with 93:7:0.5 chloroform: ethanol: cone, ammonium hydroxide provided the title compound (201 mg; 80%) as a white solid, m.p. 63-67°C R_f 0.4 (System E) Η ΝMR (300 MHz; CD₃OD): δ 8.07 and 7.91 (d, IH), 7.69 and 7.63 (d, IH), 7.55 and 7.39 (dd, IH), 7.24 (m, 8H), 7.10 and 7.05 (m, 2H), 6.99 (m, 2H), 6.80 (m, 2H), 5.19 (m, IH), 5.00 and 4.98 (s, IH), 4.65-4.49 (m, 2H), 3.76 (s, 3H), 3.09-2.79 (m, 2H), 2.88 and 2.86 (s, 3H), 1.55 (s, 9H) Example 7

4-(2- Amino-4-pyridinyl)-2- \(2 ,2-diphenylacetyl)amino1 -N-f ( 1R)- 1 -(4- hydroxypheny Qethy 1] butanamide

(a) tgrr-Butyl 4-(3-f(2,2-diphenylacetyl)aminol-4-{[(lR)-l-(4-hydroxy- phenyl)ethyl1amino)-4-oxobutyl)-2-pyridinylcarbamate A solution of 4-{2-[(tgrt-butoxycarbonyl)amino]-4-pyridinyl}-2-[(2,2- diphenylacetyl)amino]butanoic acid (332 mg; 0.7 mmol; see Example 3(d) above) and l-[3-(dimemylamino)propyl]-3-ethylcarbodiimide hydrochloride (143 mg; 0.7 mmol) in tetrahydrofura dichloromethane: acetonitrile (12 mL:4 mL: 10 mL) was stirred for 10 min. before (R)-l-[4- hydroxyphenethyl] amine (93 mg; 0.7 mmol) was added. The mixture was - stirred for 48 h, then the solvents were removed and the residue was taken up in ethyl acetate, washed with dilute KHS0₄ soln., dried with sodium sulfate, filtered and evaporated. Chromatography on silica gel eluting with 93:7:0.5 chloroform: ethanol: cone, ammonium hydroxide provided the sub-title compound (187 mg; 45 %).

Η ΝMR (300 MHz; CD₃OD): δ 8.03 and 8.00 (d, IH), 7.70 and 7.65 (s, IH), 7.27 (m, 10H), 7.08 and 7.11 (d, 2H), 6.78-6.62 (m, 3H), 5.10 and 5.06 (s, IH), 4.87 (m, IH), 4.39 (m, IH), 2.60 (m, IH), 2.47 (m, IH), 2.17-1.86 (m, 2H), 1.54 (s, 9H), 1.39 (d, 3H)

(b) 4-(2-Amino-4-pyridinyl)-2-f(2,2-diphenylacetyl)amino1-N-f(lR)-l-(4- hydroxypheny Qethy 1] butanamide rgrr-Butyl 4-(3-[(2,2-diphenylacetyl)amino]-4-{[(lR)-l-(4-hydroxyphenyl)- ethyl]amino}-4-oxobutyl)-2-pyridinylcarbamate (185 mg; 0.3 mmol; from step (a) above) was dissolved in trifluoroacetic acid:dichloromethane (20 mL: 15mL) and stirred for 1.5 h. Evaporation of the solvent followed by column chromatography on silica gel eluting with 88.5: 10: 1.5 dichloromethane: methanol: cone, ammonium hydroxide provided the title compound (112 mg; 72%) as a white solid. m.p. 209-210°C

R_f 0.4 (System D)

-Η NMR (300 MHz; CD₃OD): δ 7.72 and 7.70 (d, IH), 7.29 (m, 10H),

7.11 and 7.08 (d, 2H), 6.72 and 6.69 (d, 2H), 6.37 and 6.26 (d, IH),

6.33 and 6.22 (s, IH), 5.10 and 5.06 (s, IH), 4.90 (m, IH), 4.37 (m,

IH), 2.48 (m, IH), 2.34 (m, IH), 2.10-1.79 (m, 2H), 1.38 and 1.37 (d,

3H)

Example 8

4-(2-Amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino1-N-(4-hydroxy- benzyl)-N-methylbutanamide hydrochloride

(a) 4-Hydroxybenzylformamide

4-(Aminomethyl)phenol (5.0 g; 40.6 mmol) and methyl formate (3.25 mL;

52.8 mmol) were dissolved in THF (150 mL) and heated to reflux overnight. Additional methyl formate (5 mL; 81.2 mmol) was added and the mixture was heated at reflux for 6 h. The mixture was cooled to room temperature and concentrated under vacuum to provide the sub-title compound (6.83 g; 111 %) as a yellow solid.

Η ΝMR (300 MHz; CD₃OD): δ 8.10 (s, IH), 7.10 (d, 2H), 6.75 (d,

2H), 4.29 (s, 2H)

(b) 4- { rrgrt-Butyl(dimethyl)silyl] oxy } benzy lformamide

4-Hydroxybenzylformamide (6.8; 40.6 mmol; from step (a) above), tert- butyldimethylsilyl chloride (7.5 g; 49.5 mmol), 4-NN-dimethylamino- pyridine (100 mg; 0.81 mmol) and imidazole (3.0 g, 44.1 mmol) were dissolved in DMF and stirred for 3 h. The mixture was diluted with diethyl ether and water. The layers were separated and the water layer was extracted with ether. The organic layers were combined, washed with water and brine, dried (Na₂S0₄), filtered and concentrated under vacuum. Chromatography on silica gel eluting with a gradient of 4: 1 hexanes:ethyl acetate through 1:2 hexanes:ethyl acetate provided the subtitle compound (5.36 g; 50%) as a colorless oil.

Η NMR (300 MHz; CDC1₃): δ 8.25 (s, IH), 7.15 (m, 2H), 6.70 (m, 2H), 4.42 (d, 2H), 0.98 (s, 9H), 0.20 (s, 6H)

(c) (4-{[tgrr-Butyl(dimethyl)silyl1oxy}phenyl)-N-methylmethanamine 4-{[tgrr-Butyl(dimethyl)silyl]oxy}benzylforaιamide (2.5 g; 9.4 mmol; from step ^"(b) above) was dissolved in THF (50 mL) and cooled to 0°C. Lithium aluminum hydride (0.36 g, 9.5 mmol) was added in small portions. The mixture was stirred at 0°C for 45 min and then heated to reflux for 3 h. The mixture was allowed to stand overnight at room temperature. TLC analysis of the mixture indicated ca. 80% conversion. Additional lithium aluminum hydride (200 mg; 5.4 mmol) was added and the mixture heated to reflux for 3 h. The mixture was cooled to room temperature and carefully treated with water (600 μL) followed by aqueous ΝaOH (600 μL; 3 Ν) and finally water (1.8 mL). The mixture was filtered and the filtrate concentrated under vacuum to give the subtitle compound (2.1 g; 89%) as a colorless oil.

Η ΝMR (300 MHz; CDC1₃): δ 7.18 (m, 2H), 6.80 (m, 2H), 3.68 (s, 2H), 2.43 (s, 3H), 0.98 (s, 9H), 0.19 (s, 6H)

(d) fgrr-Butyl 4-{4-r(4-{rrgrr-butyl(dimethyl)silyl1oxy}benzyl)(methyl)- amino]-3-r(2,2-diphenylacetyl)amino]-4-oxobutyl}-2-pyridinylcarbamate 4-{2-[(rgrr-Butoxycarbonyl)amino]-4-pyridinyl}-2-[(2,2-diphenylacetyl)- aminojbutanoic acid (250 mg; 0.51 mmol; see Example 3(d) above) was dissolved in THF (3 mL) and cooled to 0°C. l-(3-Dimethylaminopropyl)- 3-ethylcarbodiimide hydrochloride (147 mg; 0.767 mmol) and 1- hydroxybenzotriazole (41 mg; 0.30 mmol) were added and the mixture was stirred at 0°C for 5 min. (4-{[rgrr-Butyl(dimethyl)silyl]oxy}phenyl)- N-methylmethanamine (154 mg; 0.61 mmol; from step (c) above) was added and the mixture was stirred at 0°C for 1 h then at room temperature overnight. The mixture was diluted with water and ethyl acetate and the layers were separated. The water layer was extracted with ethyl acetate, the organic layers were combined, washed with aqueous 2 Ν KHS0₄, dried (Νa₂S0₄), filtered and concentrated under vacuum. Chromatography on silica gel eluting with a gradient of 3:5 hexane: dichloromethane through 1 :5:0.2 hexane: dichloromethane: CM A (CMA = 80: 18:2 chlorofom: methanol: cone, ammonium hydroxide) provided the sub-title - compound (240 mg; 65%) as a yellow foam. Η NMR (300 MHz; CD₃OD): δ 8.65 (m, IH), 8.05 (d, IH), 7.70 (s, IH), 7.40-7.10 (m, 10H), 7.08 (m, 2H), 6.65 (m, 2H), 5.08 (s, IH), 4.60-4.30 (m, 2H), 2.98 (s, 2H), 2.60-2.40 (m, 2H), 2.30-1.90 (m, 2H), 1.58 (s, 9H), 1.00 (s, 9H), 0.19 (s, 6H)

(e) 4-(2-Amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-hydroxy- benzyl)-N-methylbutanamide fgrf-Butyl 4-{4-[(4-{[tgrr-butyl(dimethyl)silyl]oxy}benzyl)(methyl)amino]- 3-[(2,2-diphenylacetyl)amino]-4-oxobutyl}-2 -pyridinylcarbamate (503 mg; 0.696 mmol; from step (d) above) was dissolved in methanol (2 mL) and dichloromethane (2 mL). Trifluoroacetic acid (5.0 mL; 64 mmol) was added and stirred overnight at room temperature. The mixture was concentrated under vacuum. The crude product (480 mg) was re- dissolved in dichloromethane (2 mL) and trifluoroacetic acid (5 mL; 64 mmol). The mixture was heated to reflux for 1 hr, and then concentrated under vacuum to provide the sub-title compound (230 mg, 67%) as a white solid.

Η NMR (300 MHz; CD₃OD): δ 7.62 (d, IH), 7.48-7.20 (m, 11H), 7.05- 6.95 (m, 2H), 6.75-6.65 (m, IH), 6.35-6.20 (m, 2H), 5.1 (s, IH), 4.85- 4.75 (m, IH), 4.55-4.25 (m, 2H), 2.9 (s, 3H), 2.70 (s, IH), 2.6-2.2 (m, 2H), 2.10-1.80 (m, 2H)

(f) 4-(2-Amino-4-pyridinyl)-2-f(2,2-diphenylacetyl)amino1-N-(4-hydroxy- benzyl)-N-methylbutanamide hydrochloride 4-(2-Amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-hydroxy- benzyl)-N-methylbutanamide (218 mg; 0.43 mmol; from step (e) above) was suspended in diethyl ether (10 mL), then dichloromethane (ca. 7 mL) - was added until the resultant was homogeneous. Hydrogen chloride in diethyl ether (0.21 mL; 2 M; 0.42 mmol) was added to precipitate the title compound. The solvent was removed under vacuum and the residue triturated with diethyl ether. The solid was collected by filtration to provide the title compound (205 mg; 88%) as an off-white solid, m.p. 110-160°C with decomposition R_f 0.48 (System F) FAB MS (m/z) = 509

Η ΝMR (300 MHz; CD₃OD): δ 7.68 (d, IH), 7.40-7.15 (m, 12H), 7.10- 6.90 (m, IH), 6.75-6.5 (m, 3H), 5.09 (s, IH), 4.60-4.40 (m, 2H), 2.90 (s, 3H), 2.72 (s,_. lH), 2.70-2.40 (m, 2H), 2.20-1.90 (m,2H)

Example 9

3-(6-Amino-3-pyridinyl)-2-r(2,2-diphenylacetyl)amino1-N-r(lR)-l-(4- hydroxyphenyDethyllpropanamide

(a) Diethyl 2-{r(benzyloxy)carbonyl1amino)-2-((6-rbis(rgrr-butoxy- carbonyl)aminol-3-pyridinyl}methyl)malonate

Di(rg^butyl)-5-(bromome yl)-2-pyridinyldicarborιimidoate (see EP 672 658; 25 g; 64.6 mmol) and l ,8-diazabicyclo[5.4.0]undec-7-ene (19.3 mL; 128 mmol) were dissolved in acetonitrile (700 mL). Diethyl 2- {[(benzyloxy)carbonyl]amino}malonate (see Jacob et al, Synthesis, (1993) 6, 611; 20.9 g; 67.6 mmol) was added, and the mixture was stirred overnight. The solvent was removed under vacuum. The residue was - dissolved in ethyl acetate and washed with 2 M KHS0₄. The water layer was extracted with ethyl acetate. The organic layers were combined, washed with brine, dried (Νa₂S0₄), filtered, and concentrated under vacuum. Chromatography on silica gel eluting with a gradient of 5: 1.5 hexanes: ethyl acetate through 1: 1 hexanes: ethyl acetate provided the subtitle compound (20.4 g; 51 %) as a colorless oil. Η NMR (300 MHz; CD₃OD): δ 8.1 (s, IH), 7.45 (d, IH), 7.40-7.30 (m, 5H), 7.18 (d, IH), 5.18 (s, 2H), 4.30-4.18 (m, 4H), 3.63 (s, 2H), 1.38 (s, 18H), 1.23 (t, 6H)

(b) N-[(Benzyloxy)carbonyl1-2-({6-[bis(rgrr-butoxycarbonyl)amino]-3- pyridinyl } methyl)-3 -ethoxy-3-oxoalanine Diethyl 2- { [(benzyloxy)carbony 1] amino} -2-( { 6- [bis(fgrr-butoxycarbony 1)- amino]-3-pyridinyl}methyl)malonate (20.4 g; 33.1mmol; from step (a) above) was dissolved in absolute ethanol (250 mL) and water (25 mL). To this solution, 3 M ΝaOH (11.0 mL, 33.0 mmol) was added slowly, and the mixture was stirred for 1 h at room temperature. The mixture was concentrated under vacuum to provide a thick oil and water mixmre. The mixmre was diluted with ethyl acetate and 2 N KHS0₄ was added until the resultant was acidic. The water layer was separated and extracted with ethyl acetate. The organic layers were combined, washed with brine, dried (Na₂S0₄), filtered and concentrated to give the sub-title compound (17.5 g; 90%) as a thick yellow oU.

Η NMR (300 MHz;CD₃OD): δ 8.12 (s, IH), 7.45 (d, IH), 7.40-7.25 (m, 5H), 7.15 (d, IH), 5.05 (s, 2H), 4.20 (q, 2H), 3.58 (s, 2H), 1.38 (s, 18H), 1.20 (t, 3H)

(c) Ethyl 2- { f(benzy loxy)carbony 11 amino) -3 - { 6- fbis(f grr-butoxy carbony 1)- amino1-3-pyridinyl}propanoate

N-[(Benzyloxy)carbonyl]-2-({6-[bis(rgrr-butoxycarbonyl)amino1-3- pyridinyl}methyl)-3-ethoxy-3-oxoalanine (17.3 g; 29.4 mmol; from step (b) above) was dissolved in 1,4-dioxane. The mixmre was heated at reflux for 10 h. The solvent was removed under vacuum. Chromatography on silica gel eluting with a gradient of hexanes through 1 : 1 hexanes:ethyl acetate provided the sub-title compound (15.8 g; 98%) as a colorless oU. Η NMR (300 MHz; CDC1₃): δ 8.23 (s, IH), 7.53 (d, IH), 7.42-7.30 (m, 5H), 7.15 (d, IH), 5.12 (br. s, 2H), 4.65 (m, IH), 4.12 (q, 2H), 3.28- 3.08 (m, 2H), 1.43 (s, 18H), 1.25 (t, 3H)

(d) Ethyl 2-amino-3-{6-[bis(rgrr-butoxycarbonyl)amino1-3-pyridinyl}- propanoate

Ethyl 2-{[(benzyloxy)carbonyl]amino}-3-{6-[bis(tgrr-butoxycarbonyl)- amino1-3-pyridinyl}propanoate (13.4 g; 25.1 mmol; from step (c) above) was dissolved in absolute ethanol (100 mL) and purged with argon. Pd/C (10% dry; 100 mg) was added and hydrogen gas was bubbled through the solution for 1.5 h. The mixture was stirred under a hydrogen atmosphere overnight. The mixture was filtered through a pad of cellulose, and the filtrate concentrated under vacuum. The crude residue was crystallized from ethyl acetate to provide the sub-title compound (8.89 g; 86%) as an off white solid.

Η NMR (300 MHz; CDC1₃): δ 7.30 (d, IH), 7.8 (dd, IH), 7.28 (d, IH), 4.13 (q, 2H), 3.75 (t, IH), 3.03 (d, 2H), 1.40 (s, 18H), 1.23 (t, 3H)

(e) Ethyl 3-{6-fbis(rg^butoxycarbonyl)amino1-3-pyridinyl}-2-[(2,2- diphenylacetyl)aminolpropanoate

Ethyl 2-amino-3-{6-[bis(rgrr-butoxycarbonyl)amino]-3-pyridinyl}- propanoate (1.25 g; 3.05 mmol; from step (d) above) and - diisopropylethy lamine (800 μL) were dissolved in dichloromethane (10 mL) and cooled to 0°C. Diphenylacetyl chloride (740 mg; 3.05 mmol) was added, and the mixmre allowed to warm to room temperature. The mixture was dduted with saturated sodium bicarbonate. The water layer was extracted with dichloromethane. The organic layers were combined, dried (Na₂S0₄), filtered and concentrated to provide the sub-tide compound (1.62 g; 88%) as an off white foam. Η NMR (300 MHz; CD₃OD): δ 8.60 (d, IH), 8.23 (d, IH), 7.65 (dd, IH), 7.40-7.15 (m, 11H), 5.02 (s, IH), 4.70 (m, IH), 4.15 (q, 2H), 3.40- 3.00 (m, 2H), 1.40 (s, 18H), 1.20 (t, 3H)

(f) 3-{6-[Bis(rgrr-butoxycarbonyl)amino1-3-pyridinyl)-N-(2,2-diphenyl- acetyl)alanine

Ethyl 3-{6-[bis(fgrf-butoxycarbonyl)amino]-3-pyridinyl}-2-[(2,2-diphenyl- acetyl)amino]propanoate (1.6 g; 2.65 mmol; from step (e) above) was dissolved in THF (10 mL) and water (2 mL). Sodium hydroxide (106 mg; 2.65 mmol) was added and the mixture stirred for 3 h. The mixture was dUuted with dichloromethane and 2 N KHS0₄. The water layer was separated and extracted with ethyl acetate. The organic layers were combined, washed with brine, dried (Na₂S0₄), filtered and concentrated under vacuum to provide the sub-title compound (1.42 g; 93 %) as a white foam.

Η NMR (300 MHz; CD₃OD): δ 8.40 (d, IH), 8.23 (s, IH), 7.62 (d, IH), 7.35-7.10 (m, 11H), 5.03 (s, IH), 3.30-3.00 (m, 2H), 1.40 (s, 18H)

(g) Di(rgrr-butyl) 5-(2-f(2,2-diphenylacetyl)amino1-3-{r(lR)-l-(4-hydroxy- phenyl)ethyl1ammo}-3-oxopropyl)-2-pyridmyldicarbonimidoate

3-{6-[Bis(rgrf-butoxycarbonyl)amino]-3-pyridinyl}-N-(2,2-diphenylacetyl)- alanine (1.04 g; 1.81 mmol; from step (f) above) and l-[3- - (dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (381 mg; 1.99 mmol) were dissolved in tetrahydrofuran: dichloromethane: acetonitrile (40 mL:20 mL:30 mL) and stirred for 30 min. before (R)-l-[4- hydroxyphenethyl] amine (273 mg; 1.99 mmol) was added. The mixture was stirred overnight at room temperature, then the solvents were removed under vacuum. The residue was taken up in ethyl acetate: methanol, washed with dilute KHS0 soln., dried with magnesium sulfate, filtered and evaporated. The crude material was suspended in 88.5:10: 1.5 dichloromethane: methanol: cone, ammonium hydroxide, filtered and concentrated. Chromatography on silica gel eluting with 88.5:10:1.5 dichloromethane: methanol: cone, ammonium hydroxide provided partially purified compound. Re-purification on silica gel eluting with 95:5 dichloromethane: methanol provided the sub-title compound (572 mg; 45%). R_f 0.6 (System G)

Η ΝMR (300 MHz; CD₃OD): δ 8.30 and 8.20 (d, IH), 7.69 and 7.48 (dd, IH), 7.31-7.15 (m, 11H), 7.06 (m, 2H), 6.70 (m, 2H), 5.02 and 4.98 (s, IH), 4.85 (q, IH), 4.70 (dd, IH), 3.12 and 2.92 (m, 2H), 1.35 (m, 21H)

(h) 3-(6-Amino-3-pyridinyl)-2-r(2,2-diphenylacetyl)amino1-N-f(lR)-l-(4- hydroxyphenyl)ethyl]propanamide

Di(rgrr-butyl) 5-(2-[(2,2-diphenylacetyl)amino]-3-{[(lR)-l-(4-hydroxy- phenyl)ethyl]amino}-3-oxopropyl)-2-pyridmyldicarbonimidoate (572 mg; 0.82 mmol; from step (g) above) was dissolved in trifluoroacetic acid: dichloromethane (20 mL: 10 mL) and stirred for 1 h. Evaporation of the solvent followed by column chromatography on sdica gel eluting with 88.5: 10: 1.5 dichloromethane: methanol: cone, ammonium hydroxide provided the title compound (344 mg; 84%) as a white solid, mp 120-125°C R_f 0.6 (System G) API-MS m/z = 493 [M - H]^"

Η ΝMR (300 MHz; CD₃OD): δ 7.71 and 7.64 (d, IH), 7.31-7.03 (m, 12H), 6.96 (d, IH), 6.70 (m, 2H), 6.46 and 6.38 (d, IH), 5.00 and 4.96 (s, IH), 4.83 (m, IH), 4.62 (m, IH), 2.88 and 2.71 (m, 2H), 1.35 and 1.29 (d, 3H)

Example 10

The title compounds of Examples 1 to 9 were tested in Test A above and were all found to exhibit an IC₅₀ value of less than 5 μM (Y_t receptors).

Example 11

Compounds were prepared using parallel synthesis on solid support utilizing a Quest™ 210 apparatus (Argonaut Technologies), equipped with 20 reaction vessels (wells). (a) Allyl 4-(2-amino-4-pyridinyl)-2-{ [(9H-fluoren-9-ylmethoxy)carbonylj- amino}butanoate triflouroacetate was anchored to a solid support as follows. 6 g of trityl chloride resin (loading 1.24 mmol/g resin, 7.44 mmol) was treated with DMF for 15 min. resulting in swelling. The DMF was removed by filtration. Allyl 4-(2-amino-4-pyridinyl)-2-{[(9H- fluoren-9-ylmethoxy)carbonyl]amino}butanoate (10.63 g;^' 18.6 mmol) dissolved in DMF (30 mL), DIPEA (2.4 g; 18.6 mmol) and DMF (30 mL) was added to the resin. The reaction mixmre was stirred by passing a stream of nitrogen gas through the solution and was left at room temperature overnight. The solvent and excess reagents were removed by filtration and the resin was washed (3 times with each solvent) with DMF, MeOH, CH₂C1₂ and finally again with MeOH. The loading of allyl 4-(2- - amino-4-pyridinyl)-2-{[(9H-fluoren-9-ylmethoxy)carbonyl]amino}- butanoate on the resin was determined to 0.73 mmol/g (determined by the increase in weight after drying).

The amount of resin bound 2-amino-4-pyridinyl compound used in each well was 90 mg (corresponding to 0.0657 mmol/well).

(b) The (9H-fluoren-9-ylmethoxy)carbonyl (Fmoc) group was removed from the anchored 2-amino-4-pyridinyl derivative as follows:

1. The resin from step (a) above was allowed to swell in DMF for 15 minutes and the DMF was then filtered off.

2. 1 mL of 20% piperidine in DMF was added to the resin and the mixture was stirred for 15 minutes at room temperature.

3. The reagent and solvent were then filtered off and the resin was washed 3 times with DMF.

4. Step 2-3 were repeated 3 times. 5. After the final addition of DMF:piperidine, the resin was washed (3 times with each solvent) with DMF, MeOH, CH₂C1₂ and finally MeOH.

(c) The 2-amino-4-pyridinyl derivative was coupled to diphenylacetic acids {i.e. compounds of formula V as described hereinbefore in which L¹ is OH) as follows:

1. The resin from step (b) above was allowed to swell in DMF for 15 minutes and the DMF was then filtered off. 2. DMF (0.9 mL), HATU (4 eq.), DIPEA (10 eq.) and the appropriate diphenylacetic acid (5 eq.) were added to the reaction vessel and the reaction mixture was stirred at room temperature overnight. 3. The reagents and solvent were removed by filtration and the resin was washed (3 times with each solvent) with DMF, MeOH, CH₂C1₂ and finally MeOH.

(d) Allyl esters were converted to corresponding carboxylic acids as follows:

1. The resin from step (c) above was allowed to swell in dry THF for 15 minutes and the THF was then filtered off.

2. THF (0.9 mL), Pd(PPh₃)₄ (0.1 eq) and morpholine (10 eq) was added to the reaction vessel and the reaction was stirred at room temperature for 5 hours.

3. The reagents and the solvent were removed by filtration and the resin was washed (3 times with each solvent) with THF, MeOH, CH₂C1₂ and finally MeOH.

(e) Resultant carboxylic acids were coupled to benzylamines (i.e. compounds of formula VII as hereinbefore defined) as follows: 1. The resin from step (d) above was allowed to swell in DMF for 15 minutes and the DMF was then filtered off.

2. DMF (0.9 mL), HOBt (2 eq.), DIC (2 eq.) and the relevant amine (2 eq.) were added and the reaction was stirred at room temperature overnight.

3. The excess reagents and solvent were filtered off and the resin was washed (3 times with each solvent) with DMF, MeOH, CH₂C1₂ and finally MeOH.

(f) The product was cleaved from the resin as follows:

1. The resin from step (e) above was allowed to swell in CH₂C1₂ for 15 minutes and the CH₂C1₂ was then filtered off.

2. TFA:CH₂C1₂ (0.9 mL; 1: 1 by volume) was added and the reaction was stirred for 1 hour at room temperature. 3. The product and solvent were filtered down in a container and the resin was washed twice with CH₂C1₂. The solvent was removed in a vacuum centrifuge to give final products as their corresponding trifluoroacetate salts which, when necessary, were purified by HPLC chromatography.

Essentially the same synthesis protocol as that described above was also used to prepare compounds comprising a 6-amino-3-pyridinyl group, instead of a 2-amino-4-pyridinyl group, by using allyl 3-(6-amino-3- pyridinyl)-2-{[(9H-fluoren-9-ylmefhoxy)carbonyl]amino}propanoate trifluoroacetate instead of allyl 4-(2-amino-4-pyridinyl)-2-{[(9H-fluoren-9- ylmethoxy)carbonyl] amino} butanoate trifluoroacetate.

Compounds listed below were prepared in accordance with the above protocols: N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-3-(6-amino-3-pyridinyl)-2- [(2,2-diphenylacetyl)amino]propanamide (m/z = 537 (M+H)⁺); N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-3-(6-amino-3-pyridinyl)-2- {[2,2-bis(4-chlorophenyl)acetyl]amino}propanamide (m/z = 553 (M+H)⁺);

N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-3-(6-amino-3-pyridinyl)-2- {[2,2-bis(4-methoxyphenyl)acetyl]amino}propanamide (m/z = 597 (M+H)⁺); N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-3-(6-amino-3-pyridinyl)-2- {[2,2-bis(4-hydroxyphenyl)acetyl]amino}propanamide;

^-(4-{[(aminocarbonyl)amino]methyl}benzyl)-3-(6-amino-3-pyridinyl)-2- {[2-(4-hydroxyphenyl)-2-phenylacetyl]amino}propanamide; 3-(6-amino-3-pyridinyl)-N-[4-({[(dimethylamino)carbonyl]amino}methyl)- benzyl]-2-[(2,2-diphenylacetyl)amino]propanamide (m z = 551 (M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4- ({[(dimemylammo)carbonyl]amino}methyl)benzyl]propanamide; 3-(6-ammo-3-pyridmyl)-2-{[2,2-bis(4-memoxyphenyl)acetyl]amino}-N-[4- ( { [(dimethy lamino)carbony 1] amino} methyl)benzy ljpropanamide ; 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-[4- ({[(dimethylamino)carbonyl]amino}methyl)benzyl]propanamide;

3-(6-amino-3-pyridinyl)-N-[4-({[(dimethylamino)carbonyl]amino}methyl)- benzyl]-2-{[2-(4-hydroxyphenyl)-2-phenylacetyl]amino}propanamide; N-[4-(2-amino-2-oxoethyl)benzyl]-3-(6-amino-3-pyridinyl)-2-[(2,2- diphenylacetyl)amino]propanamide (m/z = 522 (M+H)⁺); N-[4-(2-amino-2-oxoethyl)benzyl]-3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4- chlorophenyl)acetyl]amino}propanamide (m/z = 590 (M+H)⁺); N-[4-(2-amino-2-oxoethyl)benzyl]-3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4- methoxyphenyl)acetyl]amino}propanamide (m/z = 582 (M+H)⁺); N-[4-(2-amino-2-oxoethyl)benzyl]-3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4- hydroxyphenyl)acetyl]amino}propanamide;

N-[4-(2-amino-2-oxoethyl)benzyl]-3-(6-amino-3-pyridinyl)-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}propanamide (m z = 538 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-(2- hydroxyethyl)benzyl]propanamide (m z = 509 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4-(2- hydroxyethyl)benzyl]propanamide (m/z = 577 (M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-[4-

(2-hydroxyethyl)benzyl]propanamide (m/z = 569 (M+H)⁺);

3-(6-ammo-3-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-[4- -

(2-hydroxyethyl)benzyl]propanamide (m/z = 541 (M+H)⁺);

3 -(6-amino-3-pyridinyl)-N- [4-(2-hydroxy ethyl)benzy 1] -2- { [2-(4- hydroxyphenyl)-2-phenylacetyl]amino}propanamide;

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-

(hydroxymethyl)benzyl]propanamide (m z = 495 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4-

(hydroxymethyl)benzyl]propanamide (m z = 563 (M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-[4-

(hydroxymethyl)benzyl]propanamide (m z = 555 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-[4-

(hydroxymethyl)benzyl]propanamide (m/z = 527 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-[4-(hydroxymethyl)benzyl]-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}propanamide;

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4- hydroxybenzy propanamide;

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-(4- hydroxybenzy l)propanamide ; 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-(4- hydroxybenzy l)propanamide ;

3-(6-amino-3-pyridinyl)-N-(4-hydroxybenzyl)-2-{[2-(4-hydroxyphenyl)-2- pheny lacety 1] amino} propanamide ; 3-(6-amino-3-pyridinyl)-N-(l ,3-benzodioxol-5-ylmethyl)-2-[(2,2- diphenylacetyl)amino]propanamide (m/z = 509 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- chlorophenyl)acetyl]amino}propanamide (m z = 577 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-(l ,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- methoxyphenyl)acetyl]amino}propanamide (m/z = 569 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- hydroxyphenyl)acetyl]amino}propanamide (m/z = 541 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2-(4- hydroxyphenyl)-2-pheny lacety 1] amino}propanamide ; N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-4-(2-amino-4-pyridinyl)-2-

[(2,2-diphenylacetyl)amino]butanamide (m/z = 551 (M+H)⁺);

/V-(4- {[(aminocarbonyl)amino] methyl} benzy l)-4-(2-amino-4-pyridiny l)-2-

{[2,2-bis(4-chlorophenyl)acetyl]amino}butanamide (m/z = 619 (M+H)⁺);

N-(4-{[(aminocarbonyl)amino]methyl}benzyl)-4-(2-amino-4-pyridinyl)-2- {[2,2-bis(4-methoxyphenyl)acetyl]amino}butanamide (m z = 611

(M+H)⁺);

^-(4-{[(aminocarbonyl)amino]methyl}benzyl)-4-(2-amino-4-pyridinyl)-2-

{[2,2-bis(4-hydroxyphenyl)acetyl]amino}butanamide;

^-(4-{[(aminocarbonyl)amino]methyl}benzyl)-4-(2-amino-4-pyridinyl)-2- { [2-(4-hydroxypheny l)-2-phenylacety 1] amino} butanamide ;

4-(2-ammo-4-pyridinyl)-N-[4-({[(dimethylamino)carbonyl]amino}methyl)- benzyl]-2-[(2,2-diρhenylacetyl)amino]butanamide;

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4-

( { [(dimethy lamino)carbony 1] amino} methyl)benzy 1] butanamide ; 4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-[4-

({[(dimethylamino)carbonyl]amino}methyl)benzyl]butanamide;

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-[4-

( { [(dimethylamino)carbony 1] amino} methyl)benzy 1] butanamide ; 4-(2-amino-4-pyridinyl)-N-[4-({[(dimethylamino)carbonyl]amino}methyl)- benzyl]-2-{[2-(4-hydroxyphenyl)-2-phenylacetyl]amino}butanamide;

N-[4-(2-amino-2-oxoethyl)benzyl]-4-(2-amino-4-pyridinyl)-2-[(2,2- diphenylacetyl)amino]butanamide (m/z = 536 (M+H)⁺);

N-[4-(2-amino-2-oxoethyl)benzyl]-4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4- chlorophenyl)acetyl]amino}butanamide (m/z = 604 (M+H)⁺);

N-[4-(2-amino-2-oxoethyl)benzyl]-4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4- methoxyphenyl)acetyl]amino}butanamide (m/z = 596 (M+H)⁺);

N-[4-(2-amino-2-oxoethyl)benzyl]-4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4- hydroxyphenyl)acetyl]amino}butanamide; N-[4-(2-amino-2-oxoethyl)benzyl]-4-(2-amino-4-pyridinyl)-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}butanamide;

4-(2-amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-(2- hydroxyethyl)benzyl]butanamide (m/z = 523 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4-(2- hydroxy ethyl)benzyl] butanamide (m/z = 591 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-[4-

(2-hydroxyethyl)benzyl]butanamide (m/z = 583 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-[4-

(2-hydroxyethyl)benzyl]butanamide (m/z = 555 (M+H)⁺); 4-(2-amino-4-pyridinyl)-N-[4-(2-hydroxyethyl)benzyl]-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}butanamide (m z = 539 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-

(hydroxymethyl)benzyl]butanamide (m/z = 509 (M+H)⁺); 4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-[4-

(hydroxymethyl)benzyl]butanamide (m z = 577 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-[4-

(hydroxymethyl)benzyl]butanamide (m/z = 569 (M+H)⁺); 4-(2-amino-4-pyridinyl)-2- { [2 , 2-bis(4-hydroxypheny l)acety 1] amino } -N- [4-

(hydroxymethyl)benzyl]butanamide (m z = 541 (M+H)⁺);

4-(2-amino-4-pyridinyl)-N-[4-(hydroxymethyl)benzyl]-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}butanamide (m/z = 525 (M+H)⁺);

4-(2-ammo-4-pyridmyl)-2-{[2,2-bis(4-cUorophenyl)acetyl]amino}-N-(4- hydroxybenzyl)butanamide;

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-(4- hy droxy benzy l)butanamide ;

4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-(4- hydroxybenzyl)butanamide ; 4-(2-amino-4-pyridinyl)-N-(4-hydroxybenzyl)-2-{[2-(4-hydroxyphenyl)-2- pheny lacety 1] amino}butanamide ;

4-(2-amino-4-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-[(2,2- diphenylacet l)amino]butanamide (m/z = 523 (M+H)⁺);

4-(2-amino-4-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- chlorophenyl)acetyl]amino}butanamide (m z = 591 (M+H)⁺);

4-(2-amino-4-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- methoxyphenyl)acetyl]amino}butanamide (m z = 583 (M+H)⁺);

4-(2-amino-4-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2,2-bis(4- hydroxyphenyl)acetyl]amino}butanamide (m/z = 555 (M+H)⁺); 4-(2-amino-4-pyridinyl)-N-(l,3-benzodioxol-5-ylmethyl)-2-{[2-(4- hydroxyphenyl)-2-phenylacetyl]amino}butanamide (m/z = 539 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4-

{2-[(2-hydroxyethyl)amino]-2-oxoethyl}benzyl)propanamide (m z = 634

(M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-hydroxyphenyl)acetyl]amino}-N-(4-

{2-[(2-hydroxyethyl)amino]-2-oxoethyl}benzyl)propanamide (m z = 598

(M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-(trifluoro- methyl)benzyl]propanamide (m/z = 533 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-methyl- benzy propanamide (m/z = 479 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-fluorobenzyl)- propanamide (m/z = 483 (M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4- methylbenzy propanamide (m/z = 547 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4- fluorobenzyl)propanamide (m/z = 551 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2-(4-hydroxyphenyl)-2-phenylacetyl]amino}- N-[4-(trifluoromethyl)benzyl]propanamide (m/z = 549 (M+H)⁺);

3-(6-aπιino-3-pyridinyl)-2-{[2-(4-hydroxyphenyl)-2-phenylacetyl]amino}-

N-(4-methylbenzyl)propanamide (m/z = 495 (M+H)⁺);

3-(6-anιino-3-pyridinyl)-N-(4-fluorobenzyl)-2-{[2-(4-hydroxyphenyl)-2- pheny lacety l]amino}propanamide (m/z = 499 (M+H)⁺); 3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-(4- methylbenzyl)propanamide (m/z = 539 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-{[2,2-bis(4-methoxyphenyl)acetyl]amino}-N-(4- fluorobenzyl)propanamide (m/z = 543 (M+H)⁺);

4-(2-amino-4-pyridinyl)-N-(4-{2-[(2-hydroxyethyl)amino]-2-oxoethyl}- benzyl)-2-{ [2-(4-hydroxyphenyl)-2-phenylacetyl]amino}butanamide (m/z

= 596 (M+H)⁺);

N-(4-aminobenzyl)-4-(2-amino-4-pyridinyl)-2-{[2-(4-hydroxyphenyl)-2- phenylacetyl]amino}butanamide (m/z = 510 (M+H)⁺); 4-(2-amino-4-py ridinyl)-2- [(2 , 2-dipheny lacety l)amino] -N-(4-methyl- benzyl)butanamide (m/z= 493 (M+H)⁺);

4-(2-amino-4-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-(4-fluorobenzyl)- butanamide (m/z = 497 (M+H)⁺); 4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4- methylbenzyl)butanamide (m/z = 561 (M+H)⁺); 4-(2-amino-4-pyridinyl)-2-{[2,2-bis(4-chlorophenyl)acetyl]amino}-N-(4- fluorobenzyl)butanamide (m z = 565 (M+H)⁺); and 3-(6-amino-3-pyridinyl)-N-(l ,3-benzodioxol-5-ylmethyl)-2-{[2-(4- methoxyphenyl)-2-phenylacetyl]amino}propanamide (m/z = 539 (M+H)⁺).

Example 12

The compounds listed below were made using solid phase synthesis according to the following procedure:

(a) Resin bound acid, prepared according to the procedure described in Example 11 above, using 2,2-diphenylacetic acid as the carboxylic acid, was coupled to 2-(trimethylsilyl)ethyl 4-(aminomethyl)benzylcarbamate hydrochloride, in order to produce a compound of formula I as hereinbefore defined in which R¹, R², R³, R⁵ and R⁶ are all H, n is 1, Ar¹ is a (triethylsUyl)ethoxycarbonyl (Teoc) protected 4-aminophenyl group and R⁴ is 6-amino-3-pyridinyl, anchored at the amino group), as follows. The resin bound acid (5.28 g resin corresponding to 3.75 mmol acid) was allowed to swell in DMF and the DMF was filtered off. DIPEA (1.258 mL; 7.5 mmol) and 2-(trimethylsilyl)ethyl 4-

(aminomethyl)benzylcarbamate hydrochloride (2.38 g; 7.5 mmol) dissolved in 26 mL DMF, and HOBt (1.01 g, 7.5 mmol) and DIC (0.947 g, 7.5 mmol) dissolved in 26 mL DMF, were added to the resin and the reaction were left at room temperature for 2 days. The excess reagents and solvent were filtered off and the resin was washed (3 times with each solvent) with DMF, MeOH, CH₂C1₂ and finally MeOH.

(b) The Teoc group was removed from the anchored 4-aminomethylbenzyl derivative as follows. The resin from step (a) above was allowed to swell in THF and the THF was filtered off. THF (34 mL) and tetrabutylammonium fluoride (18.8 mL of a 1 M solution in THF) were added and the reaction was left at room temperature overnight. The excess reagent and solvent were filtered off and the resin was washed (3 times with each solvent) with THF, THF: water (4: 1), MeOH, CH₂C1₂ and finally MeOH.

The parallel synthesis was carried out using a FlexChem™ Syntheisis/Fdtration block from Robins Scientific. The amount of the resin bound benzylamine used in each well was 23 mg (corresponding to 0.0173 mmol/well).

(c) The resin bound benzylamine from step (b) above was reacted with an appropriate isocyanate as follows.

1. The resin was allowed to swell in CH₂C1₂ for 30 minutes and the CH₂C1₂ was filtered off.

2. A 1.45 M solution of the appropriate isocyanate (0.25 mL, 2 eq.) in CH₂C1₂ was added to the resin and the reaction was stirred for 2 hours at room temperature.

3. The excess reagent and solvent were removed and the resin was washed with CH₂C1₂ and DMF. (d) The product was cleaved from the resin as follows. To the resin in each well from step (c) above was added CH₂Cl₂:TFA (1 : 1; 0.4 mL) and the reaction was stirred for 1.5 hours at room temperature. Removal of the resin, washing of the resin with an additional 2 x 0.2 mL CH₂C1₂:TFA (1 : 1), followed by evaporation of the solvent and excess TFA gave the final products listed below as their corresponding TFA-salts:

The following compounds were prepared:

3-(6-ammo-3-pyridmyl)-N-(4-{[(anilinocarbonyl)amino]methyl}benzyl)-2- [(2,2-diphenylacetyl)amino]propanamide (m/z = 613 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-({[(ethyl- amino)carbonyl] amino} methyl)benzyl]propanamide (m/z = 565

(M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-({[(methyl- amino)carbonyl]amino}methyl)benzyl]propanamide (m/z = 551

(M+H)⁺);

3-(6-amino-3-pyridinyl)-N-[4-({[(benzylamino)carbonyl]amino}methyl)- berj-zyl]-2-[(2,2-diphenylacetyl)amino]propanamide (m/z = 627 (M+H)⁺);

3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]-N-[4-({[(tetrahydro- 2H-pyran-2-ylamino)carbonyl]amino}methyl)benzyl]propanamide (m z =

621 (M+H)⁺);

3-(6-ammo-3-pyridmyl)-N-[4-({[(rgrf-butylamino)carbonyl]amino}methyl)- benzyl]-2-[(2,2-diphenylacetyl)amino]propanamide (m/z = 593 (M+H)⁺);

3-(6-amino-3-pyridinyl)-N-[4-({[(cyclohexylamino)carbonyl]amino}- methyl)benzyl]-2-[(2,2-diphenylacetyl)amino]propanamide (m/z = 619

(M+H)⁺); and

N- [4-( { [(allylamino)carbony 1] amino } methy l)benzyl] -3 -(6-amino-3- pyridinyl)-2-[(2,2-diphenylacetyl)amino]propanamide (m/z = 577

(M+H)⁺). Example 13

The compounds listed below was made by solid pase synthesis using the same resin bound benzylamine as that described in Example 12(b) above utilizing a VacMaster™ equipment. The amount of resin in each reaction well was 30 mg (corresponding to 0.0226 mmol/ well).

(a) The resin bound benzylamine was reacted with an appropriate chloroformiate (in order to form carbamates) as follows: 1. The resin was allowed to swell in CH₂C1₂ and the CH₂C1₂ was filtered off.

2. A CH₂C1₂ solution of the appropriate chloroformiate (0.113 mmol; 5 eq.) and N-methyl morpholine (0.0248 mmol; 1.1 eq.) was added to each well and the reaction was left at room temperature for 1 h 45 minutes.

3. The excess solvent and reagents were filtered off and the resin was washed (3 times with each solvent) with CH₂C1₂, MeOH, CH₂C1₂ and finally MeOH.

4. Steps 2 and 3 above were repeated once.

(b) The products were cleaved from the resin as follows. To each well was added CH₂C1₂:TFA (1: 1) and the reaction was left for 45 minutes. The solution was filtered, collected and freeze dried to give the final products listed below as their corresponding TFA-salts:

The following compounds were prepared: allyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 578 (M+H)⁺); methyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m z = 552 (M+H)⁺); benzyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 628 (M + H)⁺); phenyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 614 (M+H)⁺); iso-bu l 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 594 (M+H)⁺); propyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 580 (M+H)⁺); cyclopentyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m/z = 606 (M+H)⁺); and 2-propynyl 4-[({3-(6-amino-3-pyridinyl)-2-[(2,2-diphenylacetyl)amino]- propanoyl}amino)methyl]benzylcarbamate (m z = 576 (M+H)⁺).

Compounds listed in Examples 11 to 13, when tested in Test A above, exhibited an IC₅₀ value of less than 5 μM (Y_t receptors).

Example 14

3-(6-Amino-3-pyridinyl)-N-(4-fluorobenzyl)-2-{f2-(3-methoxyphenyl)-2- phenylacetyl]amino}propanamide triflouroacetate

(a) Diethyl 2- { [(benzyloxy)carbonyl] amino} -2-( { 6- [(fgrr-butoxycarbonyl)- amino1-3-pyridinyl)methyl)malonate

A mixmre of diethyl 2-{[(benzyloxy)carbonyl]amino}malonate (3.28 g; 10.6 mmol; see Jacob et al, Synthesis, (1993) 6, 611) and fgrr-butyl 5- (bromomethyl)-2-pyridinylcarbamate (3.2 g; 11.14 mmol) was treated with DBU (3.87 g; 25.4 mmol) and the resultant reaction mixture was stirred for 2.5 hours. The acetonitrile was removed and the residue was taken up in EtOAc: water (250 mL, 4: 1). The layers were separated and the organic layer was washed with 0.2 M KHS0₄ (2 x 25 mL), water (25 mL), brine (25 mL) and dried (MgS0₄). Filtration followed by evaporation provided the sub-title compound (4.92 g; 89.6 %).

LC-MS m/z = 516 (M + H)⁺

(b) N-[(Benzyloxy)carbonyl1-3-{6-r(fgt"t-butoxycarbonyl)amino1-3- pyridinyl) alanine

Diethyl 2-{[(benzyloxy)carbonyl]amino}-2-({6-[(fgrr-butoxycarbonyl)- amino]-3-pyridinyl}methyl)malonate (4.9 g; 9.5 mmol; from step (a) above) was dissolved in refluxing dioxane (110 mL), and ΝaOH (0.798 g; 19.95 mmol), dissolved in water (22 mL), was added. After 1 h and 25 minutes at reflux, ΝaOH (0.798; 19.95 mmol) was added and reflux was continued for an additional 45 minutes. The reaction was allowed to cool and the dioxane was removed. The remaining water phase was acidified with 1 M KHS0₄ and extracted with EtOAc (1 x 100 and 1 x 50 mL). The combined organic layer was washed with brine (25 mL) and dried (MgS0₄). Fdtration followed by evaporation of the solvent gave the subtitle compound (3.58 g; 90.7%).

Η-ΝMR (400 MHz; CDC1₃): δ 9.6-10.4 (two bs, 2H), 8.03 (d, IH), 7.85 (bs, IH), 7.61 (bd, IH), 7.3-7.42 (m, 5H), 5.69 (d, IH, ΝH), 5.1-5.2 (m, 2H), 4.54-4.61 (m, IH), 3.21 (d, 2 H), 1.51 (s, 9H)

(c) 3- { 6- [(rgrf-Butoxycarbonyl)aminol -3-py ridinyl ) alanine

N-[(Benzyloxy)carbonyl]-3-{6-[(fgrr-butoxycarbonyl)amino]-3-pyridinyl}- alanine (3.56 g; 8.57 mmol; from step (b) above) was dissolved in methanol (80 mL) and water (2 mL) and the mixture was hydrogenated over 5% palladium on activated carbon (3.6 g; 50% paste corresponding to 10 mol% catalyst) at atmospheric pressure for 1 hour, during which time the product had crystallised. Water (200 mL) was added and the slurry was made alkaline with 2 M NaOH in order to dissolve the product. The catalyst was then removed by filtration and the resultant solution concentrated in vacuo. The remaining alkaline water phase was neutralized with 1 M HCl and lyophUized to give the sub-title compound (2,4 g; 99.6 %) as a white powder.

Η-NMR (400 MHz; D₂0) δ 8.17 (s, IH), 7.80 (d, IH), 7.67 (d, IH), 4.01 (t, IH), 3.14-3.30 (m, 2H), 1.56 (s, 9H)

(d) N-[(Allyloxy)carbonyl1-3-{6-r(fgt -butoxycarbonyl)amino]-3-pyridinyl} alanine

A solution of 3-{6-[(rgrr-butoxycarbonyl)ammo]-3-pyridmyl}alanine (2.4 g; 8.53 mmol; from step (c) above) in water (39 mL), 2 M NaOH (11 mL) and THF (50 mL) was cooled in an ice bath, and allyl carbonochloridic acid (1.134 g; 9.4 mmol) was added and the mixmre was stirred for 2 hours. The THF was removed and the alkaline water phase was washed twice with diethyl ether (15 mL) and made acidic by addition of 20% HCl. The acidic water phase was extracted with EtOAc (1 x 100 + 1 x 50 mL). The combined organic phase was washed with water (2 x 20 mL), brine (20 mL) and dried (MgS0₄). FUtration followed by evaporation of the solvent gave the sub-title compound (2.24 g; 72 %).

Η-NMR (400 MHz, CDC1₃): δ 11-12 (bs, IH), 9.4-9.8 (bs, IH), 8.07 (d, IH), 7.88 (d, IH), 7.69 (dd, IH), 5.91-6.03 (m, IH), 5.66 (d, IH, NH), 5.36 (dd,lH), 5.27 (dd, IH), 4.55- 4.70 (m, 3H), 3.16-3.26 (m, 2H), 1.52 (s, 9H) (e) Allyl l-({6-[(rgrr-butoxycarbonyl)amino1-3-pyridinyl}methyl)-2-r(4- fluorobenzyl)amino]-2-oxoethylcarbamate

N-[(Allyloxy)carbonyl]-3-{6-[(rgrf-butoxycarbonyl)amino]-3-pyridinyl}- alanine (2.24 g; 6.14 mmol; from step (d) above) was dissolved in CH₃CΝ (50 mL) and (4-fluorophenyl)methanamine (0.845 g; 6.75 mmol) was added (a precipitate was formed) followed by DIPEA (3.17 g, 24.5 mmol). The slurry was cooled in an ice bath and TBTU (2.47 g; 7.69 mmol) was added and the reaction was allowed to reach room temperature. DMF (20 mL) was added and the slurry was stirred for another 45 minutes. The solvent was evaporated and water: MeOH (50 mL; 1 : 1) was added to the residue and the mixture was stirred for 10 minutes. The precipitate was filtered and washed with 1 x 40 mL water:MeOH (40 mL; 1: 1) and THF (30 mL). The filter cake was then dissolved in THF, and the THF was removed in vacuo to give the sub-title compound (1.87 g; 64%).

LC-MS m z = 473 (M+H)⁺

(f) tert-Bu l 5-{2-amino-3-[(4-fluorobenzyl)aminol-3-oxopropyl}-2- pyridinylcarbamate

To a slurry of allyl l-({6-[(tg/ -butoxycarbonyl)amino]-3-pyridinyl}- methyl)-2-[(4-fluorobenzyl)amino]-2-oxoethylcarbamate (1.85 g; 3.92 mmol; from step (e) above) in THF (50 mL) was added triphenylphosphine (0.411 g; 1.57 mmol) and tris(dibenzylidineacetone)dipalladium(0) (0.179 g; 0.196 mmol) and the flask was flushed with nitrogen. Dimethyl malonate (3.62 g; 27.44 mmol) was added and the slurry was stirred for 4 hours at room temperature after which the slurry had dissolved. The THF was removed and the residue was taken up in EtOAc (75 mL). The EtOAc phase was washed with water (15 mL) and extracted with 0.5 M HCl (2 x 20 mL). The combined acid/water phase was washed with diethyl ether (10 mL), made alkaline with 3.75 M NaOH and extracted with EtOAc (lx 50 mL + 1 x 25 mL). The combined organic phase was washed with 1 x 10 mL brine and dried. Filtration and evaporation gave 1.344 g of a crude product which was purified by preparative HPLC using a gradient of 0.1 M NH₄OAc:CH₃CN (95:5 to 0: 100) to give the sub-title compound.

LC-MS m/z = 389 (M + H)⁺.

(o) fgrf-Butyl 5-(3-r(4-fluorobenzyl)amino1-2-{r2-(3-methoxyphenyl)-2- phenylacetyl1amino)-3-oxopropyl)-2 -pyridinylcarbamate To a slurry of rgt -butyl 5-{2-ammo-3-[(4-fluorobenzyl)amino]-3- oxopropyl}-2-pyridinylcarbamate (0.1 g; 0.257 mmol; from step (f) above), 2-(3-methoxyphenyl)-2-phenylacetic acid (0.0624 g; 0.257 mmol) and DIPEA (0.133 g; 1.029 mmol) in acetomtrile (1.5 mL) was added TBTU (0.105 g; 0.327 mmol) and the reaction was stirred at room temperature for 30 minutes. A white precipitate was formed which was filtered off, washed with acetonitrile, water and dried to give the sub-tide compound (0.136 g, 86%).

(h) 3-(6-Amino-3-pyridinyl)-N-(4-fluorobenzyl)-2-{f2-(3-methoxyphenyl)- 2-phenylacetyllamino}propanamide triflouroacetate fgrf-Butyl 5-(3-[(4-fluorobenzyl)amino]-2-{[2-(3-methoxyphenyl)-2- phenylacetyl]amino}-3-oxopropyl)-2-pyridinylcarbamate (0.131 g; 0.214 mmol; from step (g) above) was dissolved in CH₂C1₂:TFA (3: 1; 4 mL) and the solution was stirred for 2 hours at room temperature. The solvent was removed and the residue was triturated with MeOH: water to give the title compound (0.113 g; 84 %). LC-MS m/z = 513 (M+H)⁺

Example 15

3-(6-Amino-3-pyridinyl)-2-{[2-(3-chlorophenyl)-2-phenylacetyl1amino}-N-

(4-fluorobenzyl)propanamide

The title compound was prepared according to the procedure described in

Example 14 above, replacing 2-(3-methoxyphenyl)-2-phenylacetic acid with 2-(3-chlorophenyl)-2-phenylacetic acid in step (g).

LC-MS m/z = 517 (M+H)⁺

Example 16

3-(6-Amino-3-pyridinyl)-2-{[2-(4-chlorophenyl)-2-(4-methoxyphenyl)- acetyl]amino)-N-(4-fluorobenzyl)propanamide

The title compound was prepared according to the procedure described in Example 14 above, replacing 2-(3-methoxyphenyl)-2-phenylacetic acid with 2-(4-chlorophenyl)-2-(4-methoxyphenyl)acetic acid in step (g).

LC-MS m/z = 547 (M+H)⁺

The title compounds listed in Examples 14 to 16, when tested in Test A above, exhibited an IC₅₀ value of less than 5 μM (Yj receptors).

Abbreviations

ACE = angiotensin-converting enzyme

At = 7-azabenzotriazole

Bt = benzotriazole r-BuOH = tert. -butanol br = broad (in relation to NMR) d = doublet (in relation to NMR)

DBU = 1 , 8-diazabicyclo [5.4.0 ]undec-7-ene

DCC = dicyclohexylcarbodiimide dd = doublet of doublets (in relation to NMR)

DIC = diisopropylcarbodiimide

DIPEA = diisopropylethylamine

DMAP = 4-dimethylaminopyridine

DMF = N,N-dimethylformamide

DMSO = dimethylsulfoxide

EDC = l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide

Et = ethyl

EtOAc = ethyl acetate h = hour(s)

Fmoc = 9-fluorenylmethoxycarbonyl

HATU Ν-{(dimethylamino)(lH-l,2,3-triazolo[4,5-b]pyridine- l-yl)-methylene}-N-methylmethanaminium hexafluorophosphate N-oxide

HCl = hydrochloric acid

HEPES = 4-(2-hydroxyethyl)- 1 -piperazineedianesulfonic acid

HOBt = 1 -hydroxybenzotriazole

HPLC = high performance liquid chromatography m = multiplet (in relation to NMR)

Me = methyl

MeOH = methanol m.p. = melting point

NPY = neuropeptide Y

PE = polyethylene Ph = phenyl

Py = pyridyl q = quartet (in relation to NMR) rt = room temperature s = singlet (in relation to NMR)

Su = succinimide t = triplet (in relation to NMR)

TBTU = 0-(benzotriazol-l-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate Teoc = 2-(trimethylsilyl)ethoxycarbonyl

TFA = trifluoroacetic acid

THF = tetrahydrofuran

TLC = thin layer chromatography

Ts = /7-toluenesulfonyl

Claims

Claims

1. A compound of formula I,

,R⁴

wherein

n represents 1 , 2 or 3;

Ar¹ represents a structural fragment of the formula

or represents 1- or 2-naphthyl, which latter group is optionally substimted by one or more substituents selected from OH, halo and C_1-7 alkoxy; R⁷ represents H or OH;

R⁸ represents H, halo, C_1-7 alkyl, -(CH₂)_mOR¹⁶, -(CH₂)_mN(R¹⁶)R¹⁷, -(CH₂)_pC(0)N(R¹⁶)R¹⁷, -(CH₂)_pC(0)N(R¹⁷)CH₂C(0)OR¹⁶, -(CH₂)_pN(R¹⁸)C(0)N(R¹⁶)R¹⁷, -(CH₂)_pN(R¹⁷)C(0)N(R¹⁸)CH₂C(0)OR¹⁶, -(CH₂)_pN(R¹⁷)C(0)OR^16a, -0(CH₂)_pC(0)OR¹⁶, -N(R¹⁷)(CH₂)_pC(0)OR¹⁶, or, together with either of R⁹ or R^9a, forms a methylenedioxy group; R⁹ and R^9a independently represent H, halo, OH, C_1-7 alkyl or C_1-7 alkoxy, and/or one of R⁹ and R^9a may, together with R⁸, form a methylenedioxy group;

R¹⁶ represents H, C_1-7 alkyl or -(CH₂)_q-phenyl; R^I6a represents C.,.₇ alkyl or -(CH₂)_q-phenyl; m represents 0, 1 , 2, or 3; p represents 1 , 2, 3 or 4; q represents 0 or 1 ;

R¹ represents H, C(0)NH₂ or C_M alkyl (optionally substimted and/or terminated by one or more substiments selected from hydroxy and amino);

R⁴ represents a structural fragment of formula II,

II R¹⁰ and R¹¹ independendy represent H or C_l alkyl;

R⁵ and R⁶ independently represent one or more optional substiments selected from OH, C alkyl, C_1-4 alkoxy, halo, N(R¹²)R¹³, -N(R¹⁷)CH₂C(0)OR¹⁴ and OCH₂C(0)OR¹⁵;

R², R\ R¹², R¹³, R¹⁴, R¹⁵, R¹⁷ and R¹⁸ independendy represent, at each occurrence, H or C_{1 7} alkyl;

or a pharmaceutically acceptable derivative thereof.

2. A compound as claimed in Claim 1 , wherein R¹ represents H or methyl.

3. A compound as claimed in Claim 1 or Claim 2, wherein R² represents H.

4. A compound as claimed in any one of the preceding claims, wherein R³ represents H or methyl.

5. A compound as claimed in any one of the preceding claims, wherein R⁴ represents a structural fragment of formula

6. A compound as claimed in any one of the preceding claims, wherein R⁵ is either absent or represents a single substituent selected from OH, halo, methyl and methoxy.

7. A compound as claimed in any one of the preceding claims, wherein R⁶ is either absent or represents a single substituent selected from OH, halo, methyl and methoxy.

8. A compound as claimed in any one of the preceding claims, wherein R⁷ represents H.

9. A compound as claimed in any one of the preceding claims, wherein R⁸ represents OCH₃, halo, -CH₂C(0)NH₂, -CH₂N(H)C(0)N(R¹⁶)(R¹⁷), NH₂ or OH.

10. A compound as claimed in any one of the preceding claims, wherein R⁹ represents H.

11. A compound as claimed in any one of the preceding claims, wherein R^9a represents H.

12. A compound as claimed in any one of the preceding claims, wherein R¹⁰ represents H.

13. A compound as claimed in any one of the preceding claims, wherein R^u represents H.

14. A compound as claimed in any one of the preceding claims, wherein n represents 1.

15. A compound as claimed in any one of the preceding claims, wherein R¹⁶ represents H, C_1-7 alkyl, phenyl or benzyl.

16. A compound as claimed in any one of the preceding claims, wherein R¹⁷ represents H or methyl.

17. A pharmaceutical formulation including a compound as defined in any one of Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier.

18. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use as a pharmaceutical.

19. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use in the treatment of a disorder which is mediated by neuropeptide Y.

20. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use in the treatment of a cardiovascular disease.

21. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use in the treatment of obesity.

22. The use of a compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for the manufacture of a medicament for use in the treatment of a disorder which is mediated by neuropeptide Y.

23. The use of a compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for the manufacture of a medicament for use in the treatment of a cardiovascular disease.

24. The use of a compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for the manufacture of a medicament for use in the treatment of obesity.

25. A method of treatment of a cardiovascular disease, which method comprises administration of a therapeutically effective amount of a compound as defined in any one of Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, to a person suffering from, or susceptible to, such a condition.

26. A method of treatment of obesity, which method comprises administration of a therapeutically effective amount of a compound as defined in any one of Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, to a person suffering from, or susceptible to, such a condition.

27. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use in the treatment of a disorder which is mediated by neuropeptide Y sub-receptor Y^

28. A compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for use in the treatment of vasoconstriction.

29. The use of a compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for the manufacture of a medicament for use in the treatment of a disorder which is mediated by neuropeptide Y sub-receptor Y^

30. The use of a compound as defined in any one Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, for the manufacture of a medicament for use in the treatment of vasoconstriction.

31. A method of treatment of vasoconstriction, which method comprises administration of a therapeutically effective amount of a compound as defined in any one of Claims 1 to 16, or a pharmaceutically acceptable derivative thereof, to a person suffering from, or susceptible to, such a condition.

32. A process for the preparation of a compound of formula I, as defined in Claim 1, which comprises:

(a) reaction of a compound of formula IV,

. R⁴

wherein Ar¹, R¹, R², R³, R⁴ and n are as defined in Claim 1, with a compound of formula V,

wherein L¹ represents a leaving group and R⁵ and R⁶ are as defined in Claim 1; (b) reaction of a compound of formula VI,

wherein L¹ is as defined above and R⁴, R⁵, R⁶ and n are as defined in Claim 1, with a compound of formula VII,

wherein Ar¹, R¹, R² and R³ are as defined in Claim 1;

(c) conversion of one R⁵ and/or R⁶ substituent to another;

(d) conversion of one substituent on Ar¹ to another; or

(e) deprotection of a protected derivative of a compound of formula I as defined in Claim 1.

33. A process as claimed in Claim 32 wherein, in the compound of formula I, R⁸ represents -CH₂N(H)C(0)N(H)R¹⁶, wherein R¹⁶ is as defined in Claim 1 , which process comprises reaction of a corresponding compound of formula I in which R⁸ represents -CH₂NH₂ with a compound of formula R¹⁶NCO, wherein R¹⁶ is as defined in Claim 1.

34. A process as claimed in Claim 32 wherein, in the compound of formula I, R⁸ represents -CH₂N(H)C(0)OR^16a, wherein R^16a is as defined in Claim 1, which process comprises reaction of a corresponding compound of formula I in which R⁸ represents -CH₂NH₂ with a compound of formula R^16aOC(0)Hal, in which R^16a is as defined in Claim 1 and Hal represents CI, Br or I.

35. A compound of formula VIII,

or a protected derivative thereof, wherein L² represents a leaving group and R⁴ and n are as defined in Claim 1.