GB2567126A

GB2567126A - PBC compounds

Info

Publication number: GB2567126A
Application number: GB1710054.6A
Authority: GB
Inventors: Edwin Thurston David; Joseph Mark Jackson Paul; Mirazur Rahman Khondake
Original assignee: Femtogenix Ltd
Current assignee: Femtogenix Ltd
Priority date: 2017-06-23
Filing date: 2017-06-23
Publication date: 2019-04-10
Also published as: GB201710054D0

Abstract

A compound of formula (I) or salts or solvates thereof, wherein the dotted lines indicate the optional presence of a double bond; m is 0 or 1; n is 0 or 1; m+n=0 or 1; and when m+n=1 then A is C=O and W is absent; and when m+n=0 then one of A or W is C=O and the other is CH2; and either: (i) R8 and R9 together form a double bond; (ii) R8 is H and R9 is OH; (iii) R8 is H and R9 is ORA and RA is C1-6 alkyl; or (iv) R8 is selected from SO3H, nitrogen protecting groups, C1-6 alkyl and R14; and R9 is H; wherein (a) the compound is a dimer with each monomer being the same or different and being of formula (I) where one of R1, R2 and R6 of the first monomer and one of R’1, R’2 and R’6 of the second monomer form together a bridge having the formula –X-L-X’- linking the monomers; and the remaining of R1, R2, R’1, R’2, R6 and R’6 that do not form the bridge are as herein defined; or (b) one of R1 and R2 has the formula: –X-L-X’-D; and the remaining one of R1 and R2 is selected from H, R, =O, =CH-R, =CH2, R14, (CH2)j-SO2R, O-SO2R, COR, CN, (C1-12 alkylene)-C(O)NR’’R’’’, (C2-12 alkenylene)-C(O)NR’R’’ and halo; and R6 is as herein defined; or (c) R6 has the formula: –X-L-X’-D; or is: -(CH2)g-O-R13; wherein R13 is selected from H and R; g is 0 or 1; and R1 and R2 are as herein defined; and wherein R3, R4, R5, R7, R, R’, R’’, R’’’, j, k, X, L, X’ and D are as herein defined. Said compounds for use in the treatment of a proliferative disease.

Description

The invention relates to pyrrolobenzodiazocines (PBCs) and in particular to PBC dimers comprising two PBC monomers linked together, and to PBC monomers linked to aromatic groups, and pharmaceutically acceptable salts thereof, which are useful as medicaments, in particular as anti-proliferative agents.

BACKGROUND TO THE INVENTION

Pyrrolobenzodiazocines (PBCs) are related structures to pyrrolobenzodiazepines (PBDs). The pyrrolobenzodiazepines (PBDs) are a group of compounds some of which have been shown to be sequence-selective DNA minor-groove binding agents. The PBDs were originally discovered in Streptomyces species (1-5). They are tricyclic in nature, and are comprised of an anthranilate (A ring), a diazepine (B ring) and a pyrrolidine (C ring) (3). They are characterized by an electrophilic Nio=Cn imine group (as shown below) or the hydrated equivalent, a carbinolamine [NH-CH(OH)], or a carbinolamine alkyl ether ([NH-CH(OR, where R = alkyl)] which can form a covalent bond to a C2-amino group of guanine in DNA to form a DNA adduct (6).

Carbinolamine

Imine

Carbinolamine alkyl ether

The natural products interact in the minor groove of the DNA helix with excellent fit (i.e., good “isohelicity”) due to a right-handed longitudinal twist induced by a chiral Cua-position which has the (S)-configuration (6). The DNA adduct has been reported to inhibit a number of biological processes including the binding of transcription factors (7-9) and the function of enzymes such as endonucleases (10,11) and RNA polymerase (12). PBD monomers (e.g., anthramycin) have been shown by footprinting (6), NMR (13,14), molecular modeling (15) and X-ray crystallography (16) to span three base pairs and to have a thermodynamic preference for the sequence s’-Pu-G-Pu3’ (where Pu = purine, and G is the reacting guanine) (17) and a kinetic preference for Py-5-Py (where Py = Pyrimidine).

PBDs are thought to interact with DNA by first locating at a low-energy binding sequence (i.e., a 5’-Pu-G-Pu-3’ triplet) through Van der Waals, hydrogen bonding and electrostatic interactions (7). Then, once in place, a nucleophilic attack by the exocyclic C2-amino group of the central guanine occurs to form the covalent adduct (7). Once bound, the PBD remains anchored in the DNA minor groove, avoiding DNA repair by causing negligible distortion of the DNA helix (16). The ability of PBDs to form an adduct in the minor groove and crosslink DNA enables them to interfere with DNA processing and, hence, their potential for use as antiproliferative agents.

A number of monomeric PBD structures have been isolated from Streptomyces species, including anthramycin (18) the first PBD, tomaymycin (19), and more recently usabamycin (20) from a marine sediment Streptomyces species in a marine sediment.

This has led to the development of a large range of synthetic analogues which have been reviewed (1, 21). More recently, a number of monomeric PBD structures that are linked through their C8 position to pyrroles and imidazoles have been reported WO 2007/039752, WO 2013/164593 (22-26).

In addition to monomeric PBD structures, a large range of synthetic PBD dimers (i.e. two PBD structures linked via a spacer) have been developed. Early C7- and C8-linked examples (28, 29) were designed to span greater lengths of DNA than the PBD monomers, to have enhanced sequence-selectivity, and to form DNA cross-links that might be more difficult for tumour cells to repair. In particular, the C8 position of the A ring has been extensively utilized for the production of PBD dimers (29, 30). The synthesis of various PBD dimers has been reviewed (1, 21).

Various PBDs have been shown to act as cytotoxic agents in vitro, for example, WO 00/12508, WO 2004/087711, and as anti-tumour agents in vivo in animal tumour models, for example, WO 2011/117882, WO 2013/164593. Furthermore, the C8/C8’linked PBD dimer SJG-136 (29,32) has completed Phase I clinical trials for leukaemia and ovarian cancer (31) and has shown sufficient therapeutic benefit to progress to Phase II studies.

SJG-136

However, results from a Phase I clinical evaluation of SJG-136 revealed that the drug produced several adverse effects including lower-limb edema and fatigue (33).

Thus, there exists a need for further compounds related to PBDs that are therapeutically active for treating a variety of proliferative diseases.

One novel compound related to PBDs that has been prepared is an unsubstituted pyrrolobenzodiazocine (PBC) compound (shown below). This PBC compound was reported in 1997 in order to show the utility of a Staudinger/Aza Wittig cyclization (34) in the production of an 8-membered ring. However, no analogues of this compound were reported, nor were any biological tests.

PBC compound (Ref. 34)

The present invention relates to PBCs. The present invention seeks to alleviate or overcome problem(s) associated with the prior art.

SUMMARY OF THE INVENTION

The present invention provides a compound of formula (I):

and salts or solvates thereof, wherein:

the dotted lines indicates the optional presence of a double bond between Ci and C2 or C2 and C3;

R₃ is selected from H, R, =0, =CH-R, =CH₂, R₁₄, (CH₂)j-S0₂R, 0-S0₂R, COR, CN;

R4, R₅ and R₇ are independently selected from H, R, SH, SR, R_i4, N0₂, Me₃Sn and halo; each R and R’ is independently selected from optionally substituted Ci-_i2 alkyl, C₂._i2alkenyl, C₃._2O heterocyclyl, C₄._2O heterocyclalkyl, C₅._2O heterocyclalkenyl, C₃._2O heteroaryl, 3

C₄-32 heteroaralkyl, C₅-₃₂ heteroaralkenyl, C₅-_2O aryl groups C6-₃₂ aralkyl and C₇.₃₂aralkenyl;

each R” and R’” is independently selected from H, and optionally substituted Ci-_i2 alkyl; each R₁₄ is independently selected from (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j C0₂R, (CH₂)jC0₂H, 0-(CH₂)_k-NR”R”’, C(=0)-NH-(CH₂)_k-NR”R”’, C(=O)-NH-C₆H₄-(CH₂)j-R” and C(=0)-NH-(CH₂)_k-C(=NH)NR”R”’;

m is o or 1;

n is o or 1;

each j is an integer independently selected from o to 6;

each k is an integer independently selected from 1 to 6;

m + n = o or 1; and when m + n = 1 then A is C=0 and W is absent; and when m + n = o then one of A or W is C=0 and the other is CH₂;

and either:

(i) Rs and R_g together form a double bond;

(ii) Rs is H and R_g is OH; or (iii) Rs is H and R_g is 0R^A and R^A is Ci-6 alkyl;

(iv) Rs is selected from SO₃H, nitrogen protecting groups, Ci-6 alkyl and R_i4;and R_g is H;

wherein:

(a) the compound is a dimer with each monomer being the same or different and being of formula (I) where one of Ri, R₂ and R6 of the first monomer and one of R’i, R’₂ and R’6 of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers;

and the remaining of Ri and R₂ of the first monomer and the remaining of R’i and R’₂ of the second monomer that do not form the bridge are independently selected from H, R, =0, =CH-R, =CH₂, R₁₄, (CH₂)j-S0₂R, 0-S0₂R, COR, CN, (Ci_i2 alkylene)-C(O)NR”R”’, (C₂._i2 alkenylene)-C(O)NR’R” and halo;

and the remaining of R6 of the first monomer and R^ of the second monomer that do not form the bridge are independently selected from H, R, R₁₄, (CH₂)jS0₂R, 0-S0₂R, COR, CN, (Ci-₁₂ alkylene)-C(O)NR”R”’, (C₂.₁₂ alkenylene)C(O)NR’R” and halo;

or (b) one of Ri and R₂ has the formula:

-X-L-X’-D;

and the remaining one of Ri and R₂ is selected from H, R, =0, =CH-R, =CH₂, R₁₄, (CH₂)j-S0₂R, 0-S0₂R, COR, CN, (C^ alkylene)-C(O)NR”R”’, (C₂.₁₂alkenylene)-C(O)NR’R” and halo;

and R6 selected from H, R, R_i4, (CH₂)j-S0₂R, 0-S0₂R, COR, CN, (Ci-_i2 alkylene)C(O)NR”R”’, (C₂_₁₂ alkenylene)-C(O)NR’R” and halo;

or (c) R6 has the formula:

-X-L-X’-D;

or is:

-(CH₂)_g-O-R₁₃;

wherein R_i3 is selected from H and R;

g is o or 1;

and Ri and R₂ are independently selected from H, R, =0, =CH-R, =CH₂, R_i4, (CH₂)j-S0₂R, 0-S0₂R, COR, CN, (Ci-₁₂ alkylene)-C(O)NR”R”’, (C₂_₁₂ alkenylene)C(O)NR’R” and halo;

and wherein:

Xis selected from 0, S, NR”, =CR”-, CR”R”’, CR”R’”O, C(=0), C(=O)NR”, NR”C(=O), O-C(O) and C(0)-0 or is absent;

L is selected from an amino acid, a peptide chain having from 2 to 6 amino acids, an alkylene chain containing from 1 to 12 carbon atoms which may contain one or more carbon-carbon double or triple bonds, a paraformaldehyde chain -(0CH₂)i_i₂-, a polyethylene glycol chain -(0CH₂CH₂)i_6-, which chains maybe interrupted by one or more hetero-atoms and/or optionally substituted C₃__2O heteroaryl and/or C₅__2O aryl groups;

X’ is selected from 0, S, NR”, =CR”-, CR”R”’, CR”R’”O, C(=0), C(=O)NR’, NR”C(=O), O-C(O) and C(0)-0 or is absent; and

D has the formula (II) or (III):

di);

or

p is o or 1;

qis 1, 2, 3, 4, 5 or 6;

r is o or 1;

t is o or 1

Y₃ is N or CH;

Y₄ is N or CH; wherein at least one of Y₃ and Y₄ is CH;

R₁₀ is H, Z-R”, Z-C0₂R”, Z-C(=O)-NH-(CH₂)₁-₆-NR”R’”, and Z-C(=O)-NH-(CH₂)₁-₆C(=NH)NR”R”’;

Z is absent or is selected from optionally substituted C₃-_2O heteroaryl, Ci-6 alkyl substituted C₃._2O heteroaryl, -(CH₂)_S-C₃._2O heterocyclyl, and -O-(CH₂)_S-C₃._2o heterocyclyl group;

s is o, 1, 2,3 or 4;

R11 is an optionally substituted C₃__2O heteroaryl;

R_i2 is an optionally substituted C₃._2O heteroaryl; and

R15, R16, Ri₇, R18, Rig and R₂₀, are independently selected from H, C1-6 alkyl and R_i4.

Hence, all of the compounds of formula (I) contain an 8-membered B-ring that contains 6 carbon atoms and 2 nitrogen atoms.

In a further aspect, there is provided a compound of the present invention and salts or solvates thereof for use in a method of therapy.

In a further aspect, there is provided a compound of the present invention and salts or solvates thereof for use in the treatment of a proliferative disease.

In a further aspect, there is provided a pharmaceutical composition comprising a compound of the present invention and salts or solvates thereof and a pharmaceutically acceptable carrier or diluent.

In a further aspect, the present invention provides the use of a compound of the present invention and salts or solvates thereof in the manufacture of a medicament for treating a proliferative disease.

In a further aspect, the present invention provides a method of treatment of a proliferative disease comprising administering a therapeutically effective amount of a compound of the present invention and salts or solvates thereof.

In a further aspect, the compound of formula (I) and salts or solvates thereof, may be linked, either directly or indirectly, to a targeting agent (e.g., antibody, antibody fragment, hormone, etc.) to provide a targeted conjugate. The target conjugates of the present disclosure may contain one or multiple compounds of formula (I) (or salts and solvates thereof). A variety of target conjugates are known in the art and may be used with a compound of formula (I) and salts or solvates thereof. For example, in a particular aspect the target conjugate is an antibody-drug conjugate, wherein one or more compounds of formula (I) are linked, directly or indirectly, to the antibody. Therefore, the compound of formula (I) and salts or solvates thereof, may be used as a payload on a targeted conjugate.

Definitions

The following abbreviations are used throughout the specification: Alloc allyloxycarbonyl; BAIB bis(acetoxy)iodobenzene/(diacetoxyiodo)benzene; Boc tertbutoxycarbonyl; CBz benzyloxycarbonyl; DBU i,8-diazabicyclo[5.4.o]undec-7-ene; DHP dihydropyran; DMAP 4-dimethylaminopyridine; DMF dimethylformamide; DMSO dimethylsulfoxide; EDC1 i-Ethyl-3-(3-dimethylaminopropyl)carbodiimide; Et ethyl; Et₂0 diethyl ether; EtOAc ethyl acetate; EtOH ethanol; HMDST hexamethyldisilathiane; iBu iso-butyl; KOtBu potassium t-butoxide; Me methyl; MeOH methanol; PBCs pyrrolobenzodiazocines; PBDs pyrrolo[2,i-c][i,4]benzo-diazepines; PIFA phenyliodine (III) bis [trifluoroacetate]; Ph (phenyl); p-TSA/PTSA pToluenesulfonic acid; Pyr pyridine; TBAF tetrabutylammonium fluoride; TBDMSC1 tert- butyldimethylsilyl chloride; TEA triethylamine; TEMPO (2,2,6,6-tetramethylpiperidin-i-yl)oxyl; TFA trifluoroacetic acid; THF tetrahydrofuran; THP tetrahydropyranyl; Troc 2,2,2-Trichloroethyl carbonate and Ts (tosylate) p-toluene sulfonic acid.

“Optionally substituted” refers to a parent group which may be unsubstituted or which may be substituted with one or more substituents. Where the term “optionally substituted” is followed by a list of groups, e.g. “selected from optionally substituted Ci12 alkyl, C2-12 alkenyl, C₃-_2O heterocyclyl,..” then each of the listed groups may be optionally substituted. Suitably when optional substituents are present the optional substituted parent group comprises from one to three optional substituents.

“Substituted”, when used in connection with a chemical substituent or moiety (e.g., an alkyl group), means that one or more hydrogen atoms of the substituent or moiety have been replaced with one or more non-hydrogen atoms or groups, provided that valence requirements are met and that a chemically stable compound results from the substitution.

“Independently selected” is used in the context of statement that, for example, “R and R’ are independently selected from C1-12 alkyl, C2-12 alkenyl, etc.” and means that each instance of the functional group R or R’ is selected from the listed options independently of any other instance of R or R’ in the compound. Hence, for example, a C1-12 alkyl may be selected for the first instance of R in the compound and a C2-12 alkenyl may be selected for the next instance of R in the compound.

Examples of optional substituents include Ci-₇ alkyl, C₂-₇ alkenyl, C₂-₇ alkynyl, C₅-_2O aryl, C3-10 cycloalkyl, C3-10 cycloalkenyl, C₃-i₀ cycloalkynyl, C₃-_2O heterocyclyl, C₃-_2O heteroaryl, acetal, acyl, acylamido, acyloxy, amidino, amido, amino, aminocarbonyloxy, azido, carboxy, cyanato, cyano, disulphide, ether, formyl, guanidino, halo, hemiacetal, hemiketal, hydroxamic acid, hydroxyl, imidic acid, imino, isocyano, isocyanato, isothiocyano, ketal, nitro, nitroso, oxo, oxycarbonyl, oxycarboyloxy, phosphate, phosphino, phosphinyl, phosphite, phospho, phosphonate, phosphono, phosphonooxy, phosphorous acid, phosphoramidate, phosphoramidite, sulfamino, sulfamyl, sulfate, sulfhydryl, sulfinamino, sulfinate, sulfino, sulfinyl, sulfinyloxy, sulfo, sulfonamido, sulfonamino, sulfonate, sulfonyl, sulfonyloxy, thioamido, thiocarboxy, thiocyano, thioether, thiolocarboxy, thione, thionocarboxy, uredio, hydroxyl protecting groups and nitrogen protecting groups. In some aspects, each optional substituent is independently selected from R and Ri₄. In some aspects, each optional substituent is selected from C1-6 alkyl and Ri₄.

More suitably, the optional substituents may be selected from Ci-₇ alkyl, C₂-₇ alkenyl, C₂ ₇ alkynyl, C₅__2O aryl, C₃-i₀ cycloalkyl, C₃-i₀ cycloalkenyl, C₃-i₀ cycloalkynyl, C₃._2Oheterocyclyl, C₃._2O heteroaryl, acetal, acyl, acylamido, acyloxy, amidino, amido, amino, aminocarbonyloxy, azido, carboxy, cyano, ether, formyl, guanidino, halo, hemiacetal, hemiketal, hydroxamic acid, hydroxyl, imidic acid, imino, ketal, nitro, nitroso, oxo, oxycarbonyl, oxycarboyloxy, sulfamino, sulfamyl, sulfate, sulfhydryl, sulfmamino, sulfinate, sulfino, sulfinyl, sulfinyloxy, sulfo, sulfonamido, sulfonamino, sulfonate, sulfonyl, sulfonyloxy, uredio, hydroxyl protecting groups and nitrogen protecting groups.

Examples of substituents are described in more detail below.

Ci-_i2 alkyl: refers to straight chain and branched saturated hydrocarbon groups, generally having from 1 to 12 carbon atoms; more suitably Ci-₇ alkyl; more suitably Ci-6 alkyl. Examples of alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, sbutyl, i-butyl, t-butyl, pent-i-yl, pent-2-yl, pent-3-yl, 3-methylbut-i-yl, 3-methylbut-2yl, 2-methylbut-2-yl, 2,2,2-trimethyleth-i-yl, n-hexyl, n-heptyl, and the like.

“Alkylene” refers to a divalent radical derived from an alkane which may be a straight chain or branched, as exemplified by -CH₂CH₂CH₂CH₂-.

C₂-_i2 alkenyl: refers to a hydrocarbon radical having from 2 to 12 carbon atoms and at least one double bond including, but not limited to, ethenyl, 1-propenyl, 2-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl and hexenyl and the like.

The term “alkenylene” refers to a divalent radical derived from an alkenyl which may be a straight chain or branched, containing one or more double bonds, as exemplified by, -CH₂CH=CH-, or -CH₂CH(CH₃)CH=CH-CH₂-.

C₂-_i2 alkynyl: refers to a hydrocarbon radical having from to 2 to 12 carbon atoms and at least one triple bond including, but not limited to, ethynyl, 2-propynyl, 1-butynyl, 2butynyl and the like.

C₅-_2O aryl: refers to fully unsaturated monocyclic, bicyclic and polycyclic aromatic hydrocarbons having at least one aromatic ring and having a specified number of carbon atoms that comprise their ring members (e.g., C6-14 aryl refers to an aryl group having 6 to 14 carbon atoms as ring members). The aryl group may be attached to a parent group or to a substrate at any ring atom and may include one or more nonhydrogen substituents unless such attachment or substitution would violate valence requirements. Examples of aryl groups include phenyl, biphenyl, cyclobutabenzenyl, naphthalenyl, benzocycloheptenyl, azulenyl, biphenylenyl, anthracenyl, phenanthrenyl, naphthacenyl, pyrenyl, groups derived from cycloheptatriene cation, and the like. Examples of aryl groups which comprise fused rings, at least one of which is an aromatic ring, include, but are not limited to, groups derived from indanyl, indenyl, isoindenyl, tetralinyl, acenaphthenyl, fluorenyl, phenalenyl, acephenanthrenyl and aceanthrenyl.

C3-10 cycloalkyl: refers to saturated monocyclic and bicyclic hydrocarbon groups, having from 3 to 10 carbon atoms that comprise the ring or rings. Thus, a cycloalkyl represents a cyclic version of an “alkyl”. Bicyclic hydrocarbon groups may include isolated rings (two rings sharing no carbon atoms), spiro rings (two rings sharing one carbon atom), fused rings (two rings sharing two carbon atoms and the bond between the two common carbon atoms), and bridged rings (two rings sharing two carbon atoms, but not a common bond). The cycloalkyl group may be attached to a parent group or to a substrate at any ring atom unless such attachment would violate valence requirements. Suitably the C3-10 cycloalkyl is a monocyclic cycloalkyl group, more suitably a C₃_₇ cycloalkyl is a monocyclic cycloalkyl group.

Examples of monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopropyl, dimethylcyclopropyl, methyl cyclobutyl, dimethylcyclobutyl, methylcyclopentyl, dimethylcyclopentyl and methylcyclohexyl and the like. Examples of fused bicyclic cycloalkyl groups include bicyclo[2.i.o]pentanyl (i.e., bicyclo[2.i.o]pentan-i-yl, bicyclo[2.i.o]pentan-2-yl, and bicyclo[2.i.o]pentan-5yl), bicyclo[3.i.o]hexanyl, bicyclo[3.2.o]heptanyl, bicyclo[4.i.o]heptanyl, bicyclo[3.3.o]octanyl, bicyclo[4.2.o]octanyl, bicyclo[4.3.o]nonanyl, bicyclo[4.4.o]decanyl, and the like. Examples of bridged cycloalkyl groups include bicyclo[2.i.i]hexanyl, bicyclo[2.2.i]heptanyl, bicyclo[3.i.i]heptanyl, bicyclo[2.2.2]octanyl, bicyclo[3.2.i]octanyl, bicyclo[4.i.i]octanyl, bicyclo[3.3.i]nonanyl, bicyclo[4.2.i]nonanyl, bicyclo[3.3.2]decanyl, bicyclo[4.2.2]decanyl, bicyclo[4.3.i]decanyl, bicyclo[3.3.3]undecanyl, bicyclo[4.3.2]undecanyl, bicyclo[4.3.3]dodecanyl, and the like. Examples of spiro cycloalkyl groups include spiro[3.3]heptanyl, spiro[2.4]heptanyl, spiro[3.4]octanyl, spiro[2.5]octanyl, spiro[3.5]nonanyl, and the like. Examples of isolated bicyclic cycloalkyl groups include those derived from bi(cyclobutane), cyclobutanecyclopentane, bi(cyclopentane), cyclobutanecyclohexane, etc.

C3-10 cycloalkenyl: represents a cycloalkyl that contains at least one double bond, including unsaturated monocyclic hydrocarbon compounds such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, methylcyclopropenyl, dimethylcyclopropenyl, methylcydobutenyl, dimethylcydobutenyl, methylcydopentenyl, dimethylcydopentenyl and methylcydohexenyl

C3-10 cycloalkynyl: represents a cylcoalkyl that contains at least one triple bond, including unsaturated monocyclic hydrocarbon compounds such as cyclopropynyl, cyclobutynyl, cyclopentynyl, cyclohexynyl and the like.

“C3-20 heterocyclyl”: refers to saturated or partially unsaturated monocyclic, bicyclic or polycyclic groups having ring atoms composed of 3 to 20 ring atoms, whether carbon atoms or heteroatoms, of which from 1 to 10 are ring heteroatoms. Suitably, each ring has from 3 to 7 ring atoms and from 1 to 4 ring heteroatoms (e.g., suitably C₃.₅heterocyclyl refers to a heterocyclyl group having 3 to 5 ring atoms and 1 to 4 heteroatoms as ring members). The ring heteroatoms are independently selected from nitrogen, oxygen, and sulphur.

As with bicyclic cycloalkyl groups, bicyclic heterocyclyl groups may include isolated rings, spiro rings, fused rings, and bridged rings. The heterocyclyl group may be attached to a parent group or to a substrate at any ring atom and may include one or more non-hydrogen substituents unless such attachment or substitution would violate valence requirements or result in a chemically unstable compound.

Examples of monocyclic heterocyclyl groups include, but are not limited to, those derived from:

Ni: aziridine, azetidine, pyrrolidine, pyrroline, 2H-pyrrole or 3H-pyrrole, piperidine, dihydropyridine, tetrahydropyridine, azepine;

Ch: oxirane, oxetane, tetrahydrofuran, dihydrofuran, tetrahydropyran, dihydropyran, pyran, oxepin;

Si: thiirane, thietane, tetrahydrothiophene, tetrahydrothiopyran, thiepane;

0₂: dioxoiane, dioxane, and dioxepane;

0₃: trioxane;

N₂: imidazoiidine, pyrazolidine, imidazoline, pyrazoline, piperazine:

NiOj tetrahydrooxazole, dihydrooxazole, tetrahydroisoxazole, dihydroisoxazole, morpholine, tetrahydrooxazine, dihydrooxazine, oxazine;

NiSj thiazoline, thiazolidine, thiomorpholine;

N₂0i: oxadiazine;

OiSj oxathiole and oxathiane (thioxane); and

NiOiSj oxathiazine.

Examples of substituted monocyclic heterocyclyl groups include those derived from saccharides, in cyclic form, for example, furanoses, such as arabinofuranose, lyxofuranose, ribofuranose, and xylofuranse, and pyranoses, such as aliopyranose, altropyranose, glucopyranose, mannopyranose, gulopyranose, idopyranose, galactopyranose, and talopyranose.

“C3-20 Heteroaryl”: refers to unsaturated monocyclic, bicyclic or polycylic aromatic groups comprising from 3 to 20 ring atoms, whether carbon or heteroatoms, of which from 1 to 10 are ring heteroatoms. Suitably, each ring has from 3 to 7 ring atoms and from 1 to 4 ring heteroatoms. Suitably each ring heteroatom is independently selected from nitrogen, oxygen, and sulfur. The bicyclic and polycyclic may include any bicyclic or polycyclic group in which any of the above-listed monocyclic heterocycles are fused to a benzene ring. The heteroaryl group may be attached to a parent group or to a substrate at any ring atom and may include one or more non-hydrogen substituents unless such attachment or substitution would violate valence requirements or result in a chemically unstable compound.

Examples of monocyclic heteroaryl groups include, but are not limited to, those derived from:

Nj pyrrole, pyridine;

Ch: furan;

Sj thiophene;

NiOj oxazole, isoxazole, isoxazine;

N₂0i: oxadiazole (e.g. i-oxa-2,3-diazolyl, i-oxa-2,4-diazolyl, i-oxa-2,5-diazolyl, 1-oxa3,4-diazolyl);

N₃0i: oxatriazole;

N1S1: thiazole, isothiazole;

N₂: imidazole, pyrazole, pyridazine, pyrimidine (e.g., cytosine, thymine, uracil), pyrazine;

N₃: triazole, triazine; and,

N₄: tetrazole.

Examples of heteroaryl which comprise fused rings, include, but are not limited to, those derived from:

O_x: benzofuran, isobenzofuran, chromene, isochromene, chroman, isochroman, dibenzofuran, xanthene;

N_x: indole, isoindole, indolizine, isoindoline, quinoline, isoquinoline, quinolizine, carbazole, acridine, phenanthridine;

Sj benzothiofuran, dibenzothiophene, thioxanthene;

NiOj benzoxazole, benzisoxazole, benzoxazine, phenoxazine;

NiSj benzothiazole, phenothiazine;

OiSj phenoxathiin;

N₂: benzimidazole, indazole, benzodiazine, pyridopyridine, quinoxaline, quinazoline, cinnoline, phthalazine, naphthyridine, benzodiazepine, carboline, perimidine, pyridoindole, phenazine, phenanthroline, phenazine;

0₂: benzodioxole, benzodioxan, oxanthrene;

S₂: thianthrene

N₂0i: benzofurazan;

N₂Si: benzothiadiazole

N₃: benzotriazole

N₄: purine (e.g., adenine, guanine), pteridine;

The optional substituents Ci-₇ alkyl, C₂.₇ alkenyl, C₂.₇ alkynyl, C₅._2O aryl, C₃.₁₀ cycloalkyl, C₃-i₀ cycloalkenyl, C₃.₁₀ cycloalkynyl, C₃.₂₀ heterocyclyl, C₃._2O heteroaryl, whether alone or part of another substituent, may themselves optionally be substituted with one or more groups (suitably, optionally substituted with from one to three) selected from themselves and from acetal, acyl, acylamido, acyloxy, amidino, amido, amino, aminocarbonyloxy, azido, carboxy, cyanato, cyano, disulphide, ether, formyl, guanidino, halo, hemiacetal, hemiketal, hydroxamic acid, hydroxyl, imidic acid, imino, isocyano, isocyanato, isothiocyano, ketal, nitro, nitroso, oxo, oxycarbonyl, oxycarboyl oxy, phosphate, phosphino, phosphinyl, phosphite, phospho, phosphonate, phosphono, phosphonooxy, phosphorous acid, phosphoramidate, phosphoramidite, sulfamino, sulfamyl, sulfate, sulfhydryl, sulfinamino, sulfinate, sulfino, sulfinyl, sulfinyloxy, sulfo, sulfonamido, sulfonamino, sulfonate, sulfonyl, sulfonyloxy, thioamido, thiocarboxy, thiocyano, thioether, thiolocarboxy, throne, thionocarboxy, uredio, hydroxyl protecting groups and nitrogen protecting groups.

For example, when an alkyl group is optionally substituted with one or more aryl groups it forms aralkyl group. Suitably a 0β-₃₂ aralkyl where the alkyl group and aryl group(s) combined have from 6 to 32 carbon atoms. Similarly, when an alkyl group is optionally substituted with one or more heteroaryl groups it forms heteroaralkyl group. Suitably a C₄.₃₂ heteroaralkyl group where number of ring atoms in the heteroaryl group plus the number of carbon atoms in the alkyl group is from 4 to 32.

Examples of substituents are described in more detail below.

Acetal: -CHC(0R^X1)(0R^X2), wherein R^X1 and R^X2 are independently acetal substituents, for example, a Ci-7 alkyl, C2_7 alkenyl, C2_7 alkynyl, C5_2O aryl, C3-i0 cycloalkyl, C3_i0 cycloalkenyl, C3-i0 cycloalkynyl, C3_2O heterocyclyl, C3_2O heteroaryl, suitably a Ci-7 alkyl, or, in the case of a “cyclic” acetal group, R^X1 and R^, taken together with the two oxygen atoms to which they are attached, and the carbon atoms to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Examples of acetal groups include, but are not limited to, -CH(OCH3)₂, -CH(0CH₂CH₃)₂ , and CH(OCH₃)(O CH₂CH₃).

Acyl: -C(=O)R^X3, wherein R^x3 is an acyl substituent, for example, a Ci-₇ alkyl (also referred to as Ci-₇ alkylacyl or Ci-₇ alkanoyl), C₂_₇ alkenyl, C₂_₇ alkynyl, C₅__2O aryl (also referred to as C₅__2O arylacyl), C₃._1O cycloalkyl, C₃._1O cycloalkenyl, C₃._1O cycloalkynyl, C₃__2Oheterocyclyl (also referred to as C₃._2O heterocyclyl acyl), C₃._2O heteroaryl (also referred to as C₃-_2O heteroarylacyl), more suitably a Ci-₇ alkyl. Examples of acyl groups include, but are not limited to, -C(=O)CH₃ (acetyl), -C(=O)CH₂CH₃ (propionyl), -C(=O)C(CH₃)₃ (tbutyryl), and -C(=O)Ph (benzoyl, phenone).

Acylamido: -NR^X4C(=O)R^X5, wherein R^X4 and R^X;5 are suitably independently selected from a hydrogen, a Ci-7 alkyl, C2_7 alkenyl, C2_7 alkynyl, C5_2O aryl, C3-i0 cycloalkyl, C3-i0 cycloalkenyl, C3-i0 cycloalkynyl, C3_2O heterocyclyl, C3_2O heteroaryl, suitably a hydrogen or a Ci-7 alkyl, or, in the case of a “cyclic” acylamido group, R^X4 and R^Xs, taken together with the nitrogen atom to which they are attached, and the carbon atoms to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms.. Examples of acylamido groups include, but are not limited to, -NHC(=0)CH3, -NHC(=0)CH₂CH₃, NHC(=O)Ph; and the cyclic groups succinimidyl, maleimidyl, and phthalimidyl:

Ο succinimidyl maleimidyl phthalimidyl

Acyl oxy (reverse ester): -OC(=O)R^X3, wherein R^x3 is an acyl oxy substituent and suitably has any of the options listed above with regard to acyl groups. Examples of acyloxy groups include, but are not limited to, -OC(=O)CH₃ (acetoxy), -OC(=O)CH₂CH₃, OC(=O)C(CH₃)₃, -OC(=O)Ph, and -0C(=0)CH₂Ph.

Amidino: -C(=NR^X6)NR^X4R^X5 , wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido, and wherein R^x6 is selected from a hydrogen, a Ci-₇ alkyl, C₂.₇ alkenyl, C₂.₇ alkynyl, C₅._2O aryl, C₃-_i0 cycloalkyl, C₃-_i0cycloalkenyl, C₃-_i0 cycloalkynyl, C₃._2O heterocyclyl, C₃._2O heteroaryl, suitably a hydrogen or a Ci-₇ alkyl. Examples of amidine groups include, but are not limited to, C(=NH)NH₂, -C(=NH)N(CH₃)₂ and -C(=NCH₃)N(CH₃)₂.

Amido: -C(=O)NR^X4R^X5, wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido. Examples of amido groups include, but are not limited to, -C(=0)NH₂, -C(=0)NHCH₃, -C(=O)N(CH₃)₂, -C(=0)NHCH₂CH₃, and C(=0)N(CH₂CH₃)₂, as well as amido groups in which R^X4 and R^Xs, together with the nitrogen atom to which they are attached, form a heterocyclic structure as in, for example, piperidinocarbonyl, morpholinocarbonyl, thiomorpholinocarbonyi, and piperazinocarbonyl.

Amino: -NR^X4R^X·⁵, wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido. Amino groups may be primary (both R^X4 and R^Xsare H), secondary (only one of R^X4 and R^X5 is H), or tertiary (neither R^X4 and R^Xs is H), and in cationic form, may be quaternary (-⁺NR^X4R^X5R^X6 wherein R^x6 is suitably selected from the same groups as listed above for amidino). Examples of amino groups include, but are not limited to, -NH₂, -NHCH₃, -NHC(CH₃)₂, -N(CH₃) ₂ -N(CH₂CH₃)₂, and NHPh. Examples of cyclic amino groups include, but are not limited to, aziridino, azetidino, pyrrolidino, piperidino, piperazino, morpholino, and thiomorpholino.

Aminocarbonyloxy: -OC(=O)NR^X4R^xs, wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido. Examples of aminocarbonyloxy 15 groups include, but are not limited to, -0C(=0)NH2, -0C(=0)NHCH₃, 0C(=0)N(CH₃)₂, and -0C(=0)N(CH₂CH₃)₂.

Azido: -N₃.

Carboxy: -C(=0)0H

Cyanato: -OCN.

Cyano: -CN.

Disulfide: -SS-R^X3, wherein R*3 is suitably selected from the groups as listed above for acyl. Examples of disulphide groups include Ci-₇ alkyl disulfide groups which include, but are not limited to, -SSCH₃ and -SSCH₂CH₃.

Ether: -OR*³, wherein R^X3 is suitably selected from the groups as listed above for acyl. More suitably, R^ is an alkyl group, for example, a Ci-7 alkyl group, resulting in -0R^X3being an alkoxy group. Examples of Ci-7 alkoxy groups include, but are not limited to, OCH₃ (methoxy), -OCH₂CH₃ (ethoxy), -0CH₂CH₂CH₃ (n-propoxy), -0CH₂(CH₃)₂(isopropoxy), -0CH₂CH₂CH₂CH₃ (n-butoxy), -O(OCH(CH₃)-CH₂CH₃ (sec-butoxy), 0CH₂CH(CH₃)₂ (isobutoxy), and -OC(CH₃)₃ (tert-butoxy).

Formyl: -C(=O)H.

Guanidino: -NH-C(=NH)NH₂.

Halo: -F, -CI, -Br, and -I.

Hemiacetal: -CH(0H)(0R^X3), wherein R^X3 is suitably selected from the groups as listed above for acyl. Examples of hemiacetal groups include, but are not limited to, CH(0H)(0CH₃) and - CH(0H)(0CH₂CH₃).

Hemiketal: -CR^X3(OH)(OR^Xj), wherein each R^Xj is suitably independently selected from the groups as listed above for acyl. Examples of hemiketal groups include, but are not limited to, -C(CH₃)(OH)(OCH₃), -C(CH₂CH₃)(OH)(OCH₃), -C(CH₃)(OH)(OCH₂CH₃), and -C(CH₂CH₃)(OH)(OCH₂CH₃).

Hydroxamic acid: -C(=NOH)OH.

Hydroxyl: -OH.

Imidic acid: -C(=NH)OH.

Imino: =NR^X4, wherein R^X4 is suitably selected from the groups as listed above for acylamido. Examples of imino groups include, but are not limited to, =NH, =NCH₃, =NCH₂CH₃, and =NPh.

Isocyano: -NC.

Isocyanato: -NCO.

Isothiocyano: -NCS.

Ketal: -CR^X3(OR^X1)(OR^X2), where R^X1 and R^X2 are suitably selected from the groups as listed above for acetals, and R^X3 is suitably selected from the groups as listed above for acyl. Examples ketal groups include, but are not limited to, -C(CH₃)(OCH₃)₂, C(CH₃)(OCH₂CH₃)₂, -C(CH₃)(OCH₃)(OCH₂CH₃), -C(CH₂CH₃)(OCH₃)₂, -C(CH₂CH₃)(O CH₂CH₃)₂, and -C(CH₂CH₃)(OCH₃)(OCH₂CH₃).

Nitro: -N0₂.

Nitroso: -NO.

Oxo: =0.

Oxycarbonyl (ester): -C(=O)OR^X3, wherein R^X3 is suitably selected from the groups as listed above for acyl. Examples of ester groups include, but are not limited to, C(=O)OCH₃, -C(=O)OCH₂CH₃, -C(=O)OC(CH₃)₃, and -C(=O)OPh.

Oxycarboyloxy: -OC(=O)OR^X3, where R^Xj is suitably selected from the groups as listed above for acyl. Examples of oxycarboyloxy groups include, but are not limited to, OC(=O)OCH₃, -OC(=O)OCH₂CH₃, -OC(=O)OC(CH₃)₃, and -OC(=O)OPh.

Phosphate: OP(=O)(OR^X7)(OR^X8), wherein R^X7 and R^x8 are suitably independently selected from hydrogen, Ci-₇ alkyl, C₂-₇ alkenyl, C₂.₇ alkynyl, C₅._2O aryl, C₃-i₀ cycloalkyl, C₃-i₀ cycloalkenyl, C₃-i₀ cycloalkynyl, C₃_₂₀ heterocyclyl, C₃__2O heteroaryl, suitably hydrogen, Ci-₇ alkyl, C₅__2O aryl or C₃__2O heteroaryl. Examples of phosphate groups include, but are not limited to, -0P(=0)(0CH₃)₂, -0P(=0)(0CH₂CH₃)₂, OP(=O)[OC(CH₃)₃]₂ and -0P(=0)(0Ph)₂.

Phosphino: -PR^X7R^X8, wherein R^X7 and R^x8 are suitably selected from the groups as listed above for phosphate. Examples of phosphino groups include, but are not limited to, -PH₂, -P(CH₃)₂, -P(CH₂CH₃)₂, -P(C(CH₃)₃)₂, and -P(Ph)₂.

Phosphinyl: P(=0)R^XgR^X1°), wherein R^x? and R^X1° are suitably independently selected from Ci-7 alkyl, C2_7 alkenyl, C2_7 alkynyl, C5_2O aryl, C3-i0 cycloalkyl, C3_i0 cycloalkenyl, C3_ io cycloalkynyl, C3.2O heterocyclyl, C3.2O heteroaryl, suitably Ci-7 alkyl, C5.2O aryl or C3.2O heteroaryl. Examples of phosphinyl groups include, but are not limited to, P(=O)(CH3)2, -P(=0)(CH2CH3)2, -P(=O)[C(CH3)3]2 and -P(=0)(Ph)2.Phosphite: -OP(OR^X7)(OR^X8), wherein R^x and R^x8 are suitably selected from the groups as listed above for phosphate. Examples of phosphite groups include, but are not limited to, -OP(OCH3)₂, -0P(0CH₂CH₃)₂, -OP[OC(CH₃)₃]₂ and -0P(0Ph)₂Phospho: -P(=0)₂.

Phosphonate: -P(=O(OR^X7)(OR^X8), wherein R^X7 and R^x8 are suitably selected from the groups as listed above for phosphate. Examples of phosphonate groups include, but are not limited to, -P(=O)(OCH₃)₂, -P(=0)(0CH₂CH₃)₂, -P(=O)[OC(CH₃)₃]₂ and P(=0)(0Ph)₂.

Phosphono: -P(=0)(0H)₂.

Phosphonooxy: -0P(=0)(0H)₂.

Phosphorous acid: -0P(0H)₂.

Phosphoramidate: -0P(=0)(0R^X11)-NR^X12R^X13, where R^X11, R^X12 and R^X13 are phosphoramidate substituents, for example, H, Ci-₇ alkyl (optionally substituted), C₂.₇alkenyl (optionally substituted), C₂.₇ alkynyl (optionally substituted), C₅._2O aryl, C₃-_i0 cycloalkyl, C₃-i₀ cycloalkenyl, C₃-i₀ cycloalkynyl, C₃-_2O heterocyclyl, C₃._2O heteroaryl, suitably H, Ci-₇ alkyl, a C₅._2O aryl or a C₃.₂₀ heteroaryl. Examples of phosphoramidate groups include, but are not limited to, -0P(=0)(0CH₂CH₃)-N(CH₃)₂, 0P(=0)(0CH₂CH₃)-N[CH(CH₃)₂]₂, and -0P(=0)(0CH2CH2CN)-N[CH(CH₃)₂]₂.

Phosphoramidite: -0P(0R^X11)-NR^X12R^X13, where R^X11, R^X12 and R^X13 are suitably selected from the groups as listed above for phosphoramidate. Examples of phosphoramidite groups include, but are not limited to,, -0P(0CH₂CH₃)-N(CH₃)₂, -0P(0CH₂CH₃)N[CH(CH₃)₂]₂, and -0P(0CH2CH2CN)-N[CH(CH₃)₂]₂.

Sulfamino: -NR^X3S(=0)₂0H, wherein R^ is suitably selected from the groups as listed above for acyl groups. Examples of sulfamino groups include, but are not limited to, NHS(=0)₂0H and -N(CH₃)S(=0)₂0H.

Sulfamyl: -S(=O)NR^X4R^Xs, wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido. Examples of sulfamyl groups include, but are not limited to, -S(=0)NH₂, -S(=0)NHCH₃, -S(=O)N(CH₃)₂, -S(=0)NHCH₂CH₃, -S(=0)N(CH₂CH₃)₂, and -S(=O)NHPh.

Sulfate: -OS(=O)₂OR^X3; wherein R^ is suitably selected from the groups as listed above for acyl groups. Examples of sulfate groups include, but are not limited to, 0S(=0)₂0CH₃ and -0S(=0)₂0CH₂CH₃.

Sulfhydryl: -SH.

Sulfmamino: -NR^X3S(=O)R^X4, wherein R^X3 is suitably selected from the groups as listed above for acyl groups, and R^X4 is suitably selected from the groups as listed above for acylamido. Examples of sulfmamino groups include, but are not limited to, NHS(=O)CH₃ and -N(CH₃)S(=O)Ph.

Sulfinate: -S(=O)OR^X3; wherein R^X3 is suitably selected from the groups as listed above for acyl groups. Examples of sulfinate groups include, but are not limited to, -S(=O)OCH₃ and -S(=O)OCH₂CH₃.

Sulfino: -S(=O)OH, -S0₂H.

Sulfinyl: -S(=0)R^x3; wherein R^x3 is suitably selected from the groups as listed above for acyl groups. Examples of sulfinyl groups include, but are not limited to, -S(=O)CH₃and -S(=O)CH₂CH₃.

Sulfinyloxy: -OS(=O)R^X3; wherein R^x3 is suitably selected from the groups as listed above for acyl groups. Examples of sulfinyloxy groups include, but are not limited to, 0S(=0) CH₃ and -OS(=O)CH₂CH₃.

Sulfo: -S(=0)₂0H, -SO₃H.

Sulfonamido: -S(=O)₂NR^X4R^X5, wherein R^X4 and R^Xs are suitably independently selected from the groups as listed above for acylamido. Examples of sulfonamido groups include, but are not limited to, -S(=0)₂NH₂, -S(=O)₂NHCH₃, -S(=0)₂N(CH₃)₂, S(=0)₂NH(CH₂CH₃), -S(=0)₂N(CH₂CH₃)₂, and-S(=0)₂NHPh.

Sulfonamino: -NR^X4S(=O)2R^X3, where RX3 is suitably selected from the groups as listed above for acyl groups and R^X4 is suitably selected from the groups as listed above for acylamido. Examples of sulfonamino groups include, but are not limited to, NHS(=O)2CH₃ and -N(CH3)S(=0)₂Ph.

Sulfonate: -S(=O)₂R^X3, where R^X3 is suitably selected from the groups as listed above for acyl groups. Examples of sulfonate groups include, but are not limited to, -S(=O)₂OCH₃ and -S(=0)₂0CH₂CH₃.

Sulfonyl: -S(=O)₂R^X3, where R^X3 is suitably selected from the groups as listed above for acyl groups. More suitably R^X3 is a Ci-₇ alkyl group, including, for example, a fluorinated or perfluorinated Ci-₇ alkyl group. Examples of sulfone groups include, but are not limited to, -S(=O)₂CH₃, -S(=O)₂CF₃, -S(=0)₂CH₂CH₃, -S(=O)₂C₄F₉, S(=0)₂CH₂CF₃, -S(=0)₂CH₂CH₂NH₂,, -S(=0)₂Ph, 4- methylphenylsulfonyl (tosyl), 4chlorophenyl-sulfonyl (closyl), 4-bromophenylsulfonyl (brosyl), 4-nitrophenyl (nosyl), 2-naphthalenesulfonate (napsyl), and 5-dimethylaminonaphthalen-i-ylsulfonate (dansyl).

Sulfonyloxy: -OS(=O)₂R^X3, where R^X3 is suitably selected from the groups as listed above for acyl groups. Examples of sulfonyl oxy groups include, but are not limited to, OS(=O)₂CH₃ and -0S(=0)₂ CH₂CH₃.

Thioamido: -C(=S)NR^X4RX5, where R^X4 and R^X;5 are suitably independently selected from the groups as listed above for acylamido. Examples of amido groups include, but are not limited to, -C(=S)NH₂, -C(=S)NHCH₃, -C(=S)N(CH₃)₂, -C(=S)NHCH₂CH₃, and C(=S)N(CH₂CH₃)₂.

Thiocarboxy: -C(=S)SH.

Thiocyano: -SCN.

Thioether: -SRX³, wherein RX3 is suitably selected from the groups as listed above for acyl.. Examples of thioether groups include, but are not limited to, -SCH₃ and SCH₂CH₃.

Thiolocarboxy: -C(=O)SH.

Thione: =S.

Thionocarboxy: -C(=S)OH.

Ureido: -N(R^X6)CONR^X4R^X5, wherein R^ and R^X;5 are suitably independently selected from the groups as listed above for acylamido, and R^x6 is suitably selected from the groups listed above for amidino. Examples of ureido groups include, but are not limited to, -NHC0NH₂, -NHC0NHCH₃, -NHCONHCH₂CH₃, NHC0N(CH₃)₂, NHC0N(CH₂CH₃)₂, -nch₃conh₂, -NCH₃CONHCH₃, -NCH₃CONHCH₂CH₃, NCH₃CON(CH₃)₂, and -NCH₃CON(CH₂CH₃)₂.

Nitrogen protecting groups

Nitrogen protecting groups are well known in the art and are groups that block or protect the nitrogen groups from further reaction. Nitrogen protecting groups are exemplified by carbamates [such as 9-fluorenylmethyloxy-carbonyl (Fmoc)], ureas, amides, peptides, alkyl and aryl derivatives. Carbamate protecting groups have the general formula:

R*'

In this specification a zig-zag line indicates the point of attachment of the shown group (e.g. the protecting group above) to the rest of the compound of formula (I). Suitable nitrogen protecting groups may be selected from acetyl, 1-Adoc (1-Adamantyloxycarbonyl), 2-Adoc (2-adamantyloxycarbonyl), Alloc (allyloxycarbonyl), trifluoroacetyl, t-butyloxy-carbonyl (BOC), benzyloxycarbonyl (Cbz), Doc (2,4-dimethylpent-3yloxycarbonyl), ethyl carbamate, substituted ethyl carbamates, carbamates cleaved by 1,6-beta-elimination, 9-fluorenylmethyloxy-carbonyl (Fmoc), Hoc (cyclohexyloxycarbonyl), methyl carbamate, TcBOC (2,2,2-trichloro-tert-butyloxycarbonyl), Teoc [2(Trimethylsilyl)ethoxy-carbony] and Troc (2,2,2-Trichloroethyl carbonate).

A large number of possible nitrogen protecting groups are described in Wuts, P.G.M. and Greene, T.W., Protective Groups in Organic Synthesis, 4^th Edition, Wileylnterscience, 2007, e.g. pages 706 to 771 of Wuts et al. describe carbamate nitrogen protecting groups. Nitrogen protecting groups are also described in P. Kocienski, Protective Groups, 3rd Edition (2005). Both Wuts, et al. and Kocienski are incorporated herein by reference.

Hydroxyl protecting groups

Hydroxyl protecting groups are well known in the art, a large number of suitable groups are described on pages 16 to 366 of Wuts, P.G.M. and Greene, T.W., Protective Groups in Organic Synthesis, 4^th Edition, Wiley-lnterscience, 2007, and in P. Kocienski, Protective Groups, 3rd Edition (2005) which are incorporated herein by reference.

Classes of particular interest include silyl ethers, methyl ethers, alkyl ethers, benzyl ethers, esters, benzoates, carbonates, and sulfonates. Particularly preferred protecting groups include THP (tetrahydropyranyl ether).

“Drug”, “drug substance”, “active pharmaceutical ingredient”, and the like, refer to a compound (e.g., compounds of Formula 1 and compounds specifically named above) that may be used for treating a subject in need of treatment.

“Excipient” refers to any substance that may influence the bioavailability of a drug, but is otherwise pharmacologically inactive.

“Pharmaceutically acceptable” substances refers to those substances which are within the scope of sound medical judgment suitable for use in contact with the tissues of subjects without undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit-to-risk ratio, and effective for their intended use.

“Pharmaceutical composition” refers to the combination of one or more drug substances and one or more excipients.

The term “subject” as used herein refers to a human or non-human mammal. Examples of non-human mammals include livestock animals such as sheep, horses, cows, pigs, goats, rabbits and deer; and companion animals such as cats, dogs, rodents, and horses.

“Therapeutically effective amount” of a drug refers to the quantity of the drug or composition that is effective in treating a subject and thus producing the desired therapeutic, ameliorative, inhibitory or preventative effect. The therapeutically effective amount may depend on the weight and age of the subject and the route of administration, among other things.

“Treating” refers to reversing, alleviating, inhibiting the progress of, or preventing a disorder, disease or condition to which such term applies, or to reversing, alleviating, inhibiting the progress of, or preventing one or more symptoms of such disorder, disease or condition.

“Treatment” refers to the act of “treating”, as defined immediately above.

As used herein the term “comprising” means “including at least in part of’ and is meant to be inclusive or open ended. When interpreting each statement in this specification that includes the term “comprising”, features, elements and/or steps other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner.

The present invention relates to a compound of formula (I):

and salts or solvates thereof.

Rs

Suitably R₃ is selected from H, C1-12 alkyl, C2-12 alkenyl, (CH₂)jOH, O-C1-12 alkyl, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)_j-C0₂C₁-₁₂ alkyl, (CH₂)_rC0₂H, C0Ci_x₂ alkyl and CN.

Suitably R₃ is selected from H, Cx-6 alkyl, C₂.₁₂ alkenyl, OH, O-C1-6 alkyl, NH₂, NH(Ci-6 alkyl), CO₂Ci-₆ alkyl, CH₂-CO₂Ci_₆ alkyl, C0₂H and CH₂-C0₂H.

More suitably R₃ is selected from H, NH₂, NH(Ci-6 alkyl), C0₂Ci-6 alkyl, CH₂-C0₂Ci-6 alkyl, C0₂H and CH₂-C0₂H.

Suitably R4 is selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j-C0₂H, (CH₂)j-C0₂R and halo.

Suitably R4 is selected from H, Cx-₁₂ alkyl, C₃._2O heteroaryl, C₄.₃₂ heteroaralkyl, C₅._2O aryl groups, C₇_₃₂ aralkenyl, OH, 0-Cx-₁₂ alkyl, NH₂, NHR, C0₂H, CH₂-C0₂H, C0₂R, CH₂C0₂R and halo.

More suitably R4 is selected from H, Cx-6 alkyl, C₃-s heteroaryl, 06-₁₂ aryl groups, O-C1-6 alkyl, NH₂, NH(Cx-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(Cx-₆ alkyl) and CH₂-C0₂(Cx-₆ alkyl).

More suitably R4 is selected from H, NH₂, NH(Cx-6 alkyl), C0₂H, CH₂-C0₂H, C0₂(Cx-6 alkyl) and CH₂-C0₂(Cx-6 alkyl). More suitably R₄ is H.

Suitably R₅ is selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j-C0₂H, (CH₂)j-C0₂R and halo.

Suitably R₅ is selected from H, Cx_i₂ alkyl, OH, 0-Ci_x₂ alkyl, 0CH₂Ph, NH₂, NHR, NRR’, C0₂H, CH₂-C0₂H, C0₂R, CH₂-C0₂R and halo.

More suitably R₅ is selected from H, Cx-₁₂ alkyl, OH, O-Cx-6 alkyl, 0CH₂Ph, NH₂, NH(Cx-6 alkyl), C0₂H, CH₂-C0₂H, C0₂(Cx-6 alkyl) and CH₂-C0₂(Cx-6 alkyl).

More suitably R₅ is selected from H, Cx-₁₂ alkyl, O-Cx-6 alkyl and 0CH₂Ph.

Rz

Suitably R₇ is selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j-C0₂H, (CH₂)_rC0₂R’ and halo.

Suitably R₇ is selected from H, Ci-_i2 alkyl, OH, 0-Ci-_i2 alkyl, NH₂, NHR, C0₂H, CH₂C0₂H, C0₂R, CH₂-C0₂R and halo.

More suitably R₇ is selected from H, Ci-6 alkyl, O-Ci-6 alkyl, NH₂, NH(Ci-6 alkyl), C0₂H, CH₂-C0₂H, 00₂(0χ-6 alkyl) and CH₂-C0₂(C!-6 alkyl).

More suitably R₇ is selected from H, NH₂, NH(Ci-6 alkyl), C0₂H, CH₂-C0₂H, C0₂(Ci-6 alkyl) and CH₂-C0₂(Ci_6 alkyl). More suitably R₇ is H.

Rs and Ro

Suitably, Rs and R_g together form a double bond.

In one aspect (ii), Rs is H and R_g is OH.

In another aspect (iii), suitably Rs is H and R_g is OCH₃ or OCH₂CH₃.

In another aspect (iv), suitably Rs is selected from OH, SO₃H, nitrogen protecting groups, methyl, ethyl, OCH₃, OCH₂CH₃, 0CH₂Ph, (CH₂)_s-C0₂H, (CH₂)_s-C0₂CH₃, (CH₂)_s-C0₂CH₂CH₃, 0-(CH₂)_t-NH₂, O-(CH₂)_t-NH-CH₃, (CH₂)_S-NH₂, (CH₂)_S-NH-CH₃, C(=0)-NH-(CH₂)_t-NH₂, C(=O)-NH-(CH₂)_t-NH-CH₃, C(=O)-NH-C₆H₄-(CH₂)_S-H, 0(=0)NH-(CH₂)_t-C(=NH)NH₂ and C(=O)-NH-(CH₂)_t-C(=NH)NH-CH₃ and R_g is H. More suitably in this aspect (iv), Rs is selected from OH, SO₃H, methyl, ethyl, OCH₃, OCH₂CH₃, C0₂H, CO₂CH₃, C0₂CH₂CH₃, 0-(CH₂)_t-NH₂ and (CH₂)_S-NH₂ and R_g is H.

In some aspects, Rs is SO₃H and the compound of formula (I) is a salt thereof. Suitably, in this aspect, Rs is SO₃H and the compound of formula (I) is an alkali metal salt thereof (AM)⁺; hence, in this aspect, Rg maybe written as S03’(AM)⁺. Suitably, Rs is SO3H and the compound of formula (I) is an alkali metal salt thereof chosen from Li⁺, Na⁺ and K⁺. More suitably, Rs is SO3H and the compound of formula (I) is a Na⁺ salt thereof; hence, in this aspect, Rs maybe written as SO3’Na⁺.

R and R’

Suitably each R and R’ are independently selected from optionally substituted Ci-8 alkyl, C₂-8 alkenyl, C₃-i₅ heterocyclyl, C4-16 heterocyclalkyl, C₅-i₇ heterocyclalkenyl, C₃-_i0heteroaryl, C₄.₂2 heteroaralkyl, C₅_₂₃ heteroaralkenyl, C5-16 aryl groups C6-₂₂ aralkyl and C7-22 aralkenyl.

Suitably each R and R’ are independently selected from optionally substituted C1-8 alkyl, C₂-8 alkenyl, C₃-_i2 heterocyclyl, C₃-_i0 heteroaryl, C₄.₂₂ heteroaralkyl, C6-14 aryl groups and C₆ -22 aralkyl.

More suitably each R and R’ are independently selected from optionally substituted C1-6 alkyl, C₂-6 alkenyl, C₃-n heterocyclyl, C₃-s heteroaryl, C₄-i₄ heteroaralkyl, C6-12 aryl groups and Ce-18 aralkyl. More suitably, R and R’ are independently selected from C1-6 alkyl groups.

R1, R_? and Rr,

In embodiment (b) one of Ri and R₂ has the formula: -X-L-X’-D;

and the resulting compound may be represented by the following formula (Ci):

(Ci) or by the following formula (C2):

(C2) and the remaining one of Ri and R₂ is selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, =0, =CH-R, =CH₂, (CH₂)jC0₂R, (CH₂)jC0₂H, (CH₂)j-S0₂R, 0-S0₂R, COR, CN, 0-(CH₂)_k-NR”R”’, C(=0)-NH-(CH₂)_k-NR”R”’, C(=0)NH-C₆H₄-(CH₂)_rR”, C(=0)-NH-(CH₂)_k-C(=NH)NR”R”’, (Cm₂ alkylene)-C(O)NR”R”’, (C₂-i₂ alkenylene)-C(O)NR’R” and halo;

and R₆ selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH^jNRR’CCH^j-CCLR, (CH₂)j-C0₂H, (CH₂)_rS0₂R, 0-S0₂R, COR, CN, 0-(CH₂)_kNR”R’”, C(=0)-NH-(CH₂)_k-NR”R”’, 0(=0)-ΝΗ-0₆Η₄-(0Η₂)_ΓΡ”, C(=0)-NH-(CH₂)_kC(=NH)NR”R’”, (C!-₁₂ alkylene)-C(O)NR”R’”, (C₂_₁₂ alkenylene)-C(O)NR’R” and halo.

The possible options for the presence or absence of double bonds in the C-ring and for stereoisomers of the above compounds (Ci) and (C2) are set out below in the suitable structures section.

In this embodiment (b), suitably the remaining one of Ri and R₂ is selected from H, R,

(CH₂)jC0₂H, COR, (Ci-₁₂ alkylene)-C(O)NR”,R’” and (C₂.₁₂ alkenylene)-C(O)NR’R” and halo.

In this embodiment (b), suitably R6 is selected from H, R, (CH₂)jOH, (CH₂)jOR (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j-C0₂H, (CH₂)j-C0₂R and halo. Suitably R₆is selected from H, Cx-₁₂ alkyl, OH, 0-Cx-₁₂ alkyl, 0CH₂Ph, NH₂, NH(Ci-6 alkyl), C0₂H, CH₂-C0₂H, C0₂(Ci-6 alkyl), CH₂-C0₂(Ci-6 alkyl) and halo. More suitably R6 is selected from H, O-Cx-e alkyl, 0CH₂Ph, NH₂, NH(Cx-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(Cx-₆ alkyl) and CH₂-C0₂(Cx_6 alkyl).

In a further embodiment (c) R6 has the formula:

-X-L-X’-D;

or is:

-(CH₂)_g-O-R₁₃;

wherein R₁₃ is selected from H and R; g is 0 or 1;

Suitably R_i3is selected from H and Cx_i₂ alkyl; more suitably, R_i3is selected from H and C1-6 alkyl.

Where R6 has the formula: -X-L-X’-D; the resulting compound may be represented by the following formula (C3):

(C₃) and Ri and R₂ are independently selected from H, R, (CH₂)jOH, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, =0, =CH-R, =CH₂, (CH₂)jC0₂R, (CH₂)jC0₂H, (CH₂)_rS0₂R, 0S0₂R, COR, CN, 0-(CH₂)_k-NR”R”’, C(=0)-NH-(CH₂)_k-NR”R”’, 0(=0)-ΝΗ-0₆Η₄-(0Η₂)_ΓR”, C(=0)-NH-(CH₂)_k-C(=NH)NR”R”’, (Ci-₁₂ alkylene)-C(O)NR”R”’, (C₂-₁₂ alkenylene)C(O)NR’R” and halo.

In this embodiment (c), suitably Ri and R₂ are independently selected from H, R, (CH₂)jOR, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, =0, =CH-R, =CH₂, (CH₂)j-C0₂R, (CH₂)jC0₂H, COR, (Ci-₁₂ alkylene)-C(O)NR”,R”’ and (C₂_₁₂ alkenylene)-C(O)NR’R” and halo.

The possible options for the presence or absence of double bonds in the C-ring and for stereoisomers of the above compound (C3) are set out below in the suitable structures section.

R.

In embodiment (b) where Ri is -X-L-X’-D, or in embodiment (c), suitably R₂ is selected from H, R, (CH₂)jOH, (CH₂)jNH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)jC0₂R, (CH₂)j-C0₂H and (CH₂)jOR. Suitably R₂ is H, NH₂, NHR, C0₂R, CH₂-C0₂R, C0₂H, CH₂-C0₂H and an optionally substituted alkenyl, aryl, heteroaryl, aralkyl or heteroaralkyl group which contains at least one double bond which forms part of a conjugated system with a double bond of the c-ring.

In embodiment (b) where Ri is -X-L-X’-D, or in embodiment (c), more suitably, R₂ is selected from H, NH₂, NHR, C0₂R, CH₂-C0₂R, C0₂H, CH₂-C0₂H and an optionally substituted C₃-s heteroaryl and C₅-i₀ aryl group. More suitably R₂ is selected from H, NH₂, NHR, C0₂R, CH₂-C0₂R, C0₂H, CH₂-C0₂H, and an optionally substituted furanyl, pyrrolyl, thiophenyl, phenyl or napthyl group. More suitably R₂ is selected from H, NH₂, NHCCi-e alkyl), CO^C^e alkyl), CH₂-CO₂(C₁-₆ alkyl), C0₂H and CH₂-C0₂H.

R” and R’”

Suitably each R” and R’” are independently selected from H and optionally substituted C1-8 alkyl. More suitably, each R” and R’” are independently selected from H and optionally substituted C1-6 alkyl; more suitably, from H and methyl, ethyl, propyl and butyl.

i

Each j is an integer independently selected from o to 6; that is each j is independently selected from o, 1, 2, 3, 4,5 and 6.

Suitably, each j is an integer independently selected from 0 to 5; suitably independently selected from 0 to 4; suitably independently selected from 0 to 3; suitably independently selected from 0 to 2; suitably independently selected from 0 to 1.

In some aspects, j is 0.

k

Each k is an integer independently selected from 1 to 6; that is each k is independently selected from 1, 2, 3, 4, 5 and 6.

Suitably, each k is an integer independently selected from 1 to 5; suitably independently selected from 1 to 4; suitably independently selected from 1 to 3; suitably independently selected from 1 to 2.

In some aspects, k is 1.

X

Suitably X is selected from 0, NR”, =CR”-, CR”R’”O, C(=0), C(=0)NR”, NR”C(=0), 0C(0) and C(0)-0 or is absent.

Suitably, X is selected from 0, =CR”-, C(=0)NR” and NR”C(=0).

More suitably X is selected from 0, =CH-, C(=0)NH and NHC(=0).

More suitably X is 0.

X

Suitably X, is selected from 0, NR”, =CR”-, CR”R’”O, C(=0), C(=0)NR”, NR”C(=0), 0C(0) and C(0)-0 or is absent.

Suitably X’ is selected from 0, =CR”-, C(=0)NR” and NR”C(=0).

More suitably X is selected from 0, =CH-, C(=O)NH and NHC(=O).

Suitably X is the same as X’.

More suitably X’ is 0.

L

Suitably, any of the peptide chain, alkylene chain, paraformaldehyde chain or polyethylene glycol chain is interrupted by one or more hetero-atoms (e.g., N, 0 and S) and/or one or more optionally substituted C₃-_2O heteroaryl groups (e.g., pyrrolyl, pyrazolyl, pyrazolyl, 1,2,3-triazolyl, pyridinyl) and/or one or more C₅__2O aryl groups (e.g. phenyl). More suitably, the chains may be interrupted by from one to three heteroatoms and/or from one to three optionally substituted C₃._2O heteroaryl groups and/or from one to three C₅._2O aryl groups.

Suitably L is selected from a peptide chain having from 2 to 5 amino acids, from 2 to 4 amino acids, from 2 to 3 amino acids; an alkylene chain containing from 1 to 11 carbon atoms, from 1 to 10 carbon atoms, from 1 to 9 carbon atoms, from 1 to 8 carbon atoms, from 1 to 7 carbon atoms, from 1 to 6 carbon atoms, which may contain one or more carbon-carbon double or triple bonds; a paraformaldehyde chain -(OCHa)!-^-, mU, -(OCHU-K,-, -(0CHU-9-, -(0CHU-8-, -(0CHU-7-, -(OCH.)^-, -(OCHU 5-, -(OCH₂)i-₄-, -(OCH₂)i-₃- a polyethylene glycol chain -(OCH₂CH₂)i_₅-, chain (OCH₂CH₂)i-₄-, chain -(0CH₂CH₂)i_₃-; which chain may be interrupted by one or more hetero-atoms and/or optionally substituted C₃._2O heteroaryl groups and/or C₅._2O aryl groups.

More suitably, L may be selected from an alkylene chain containing from 1 to 12 carbon atoms which may contain one or more carbon-carbon double or triple bonds. More suitably, L maybe selected from CH=CH, CH₂, CH₂CH₂CH₂, CH₂CH₂CH₂CH₂ and CH₂CH₂CH₂CH₂CH₂.

D

Suitably D has the formula (II) or (III) and Ru is selected from optionally substituted N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene, thiazolylene, indolylene, N-methylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, N-methylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

Suitably D has the formula (II) or (III) and Ru is selected from optionally substituted N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene and thiazolylene.

Suitably D has the formula (II) or (III) and Ru is selected from optionally substituted indolylene, N-methylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, N-methylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

Suitably D has the formula (II) or (III) and R_i2 is selected from optionally substituted N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene, thiazolylene, indolylene, N-methylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, N-methylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

Suitably D has the formula (II) or (III) and R_i2 is selected from optionally substituted N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene and thiazolylene.

Suitably D has the formula (II) or (III) and R_i2 is selected from optionally substituted indolylene, N-methylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, N-methylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

Suitably D is selected from formula (Di):

formula (D2):

formula (D3):

and formula (D4):

L O (d₄);

wherein:

p is 0 or 1;

qis 1, 2, 3, 4, 5 or 6;

r is 0 or 1;

t is 0 or 1

Y, Y_x and Y₂ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH; CH, S and CH; CH, CH and S; N, S and CH; N,

CH and S; N, O and CH; N, CH and O; CH, CH and O; CH O and CH; COH, NCH₃ and CH; and COH, CH and N-CH₃;

Y₃ is N or CH;

Y₄ is N or CH; wherein at least one of Y₃ and Y₄ is CH;

Y₅, Y₆ and Y₇ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH; CH, S and CH; CH, CH and S; N, S and CH; N, CH and S; N, O and CH; N, CH and O; CH, CH and O; CH O and CH; COH, NCH₃ and CH; and COH, CH and N-CH₃;

Ys is selected from O, S, NH and N-CH₃;

Y_g is selected from CH and N;

Y10 is selected from 0, S, NH and N-CH₃;

Yu is selected from CH and N;

R₁₀ is H, Z-R”, Z-C0₂R”, Z-C(=0)-NH-(CH₂)₁-₆-NR”R”’, and Z-C(=0)-NH(CH₂)₁-6-C(=NH)NR”R”’;

Z is absent or is selected from optionally substituted C₃._2O heteroaryl, Ci-6 alkyl substituted C₃__2O heteroaryl, -(CH₂)_S-C₃-_2O heterocyclyl, and -0-(CH₂)_s-C₃-₂₀heterocyclyl group; and s is o, 1, 2,3 or 4.

Hence, the heteroaryl rings containing Y, Y_x and Y₂ and Y₅, Υό and Y₇ are independently selected from one of the following groups:

Hence, the heteroaryl rings containing Y₃ and Y₉, Y_iO and Yn are independently selected from one of the following groups:

H CH₃

9 a->\ ^A

Suitably heteroaryl groups containing the Ys and Y₉ groups and those containing Y_i0and Yn groups are attached to the rest of the compound at the C-2 and C-5 positions as shown below:

The aromatic ring containing Y₃ and Y₄ is a phenylene or pyridinylene group.

Suitably D is of formula (Di) or (D2) and p is o, such that D may be represented by formula (D5) or (D6):

Suitably Y, Yi and Y₂ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH. Suitably Y, Yi and Y₂ are selected from CH, N-CH₃ and CH; and N, N-CH₃ and CH.

Suitably r is 1 and Y₃ and Y₄ are CH.

Suitably Y₅, Ye and Y₇ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH. Suitably Y₅, Y₆ and Y₇ is CH, N-CH₃ and CH.

Suitably, R₁₀ is H, Z-R” and Z-C0₂R”. Suitably, R₁₀ is Η, Z-H, Z-C^ alkyl, Z-C0₂H and Z-CO₂Ci-₆ alkyl.

Suitably, Z is selected from optionally substituted C₃__2O heteroaryl and C1-6 alkyl substituted C₃._2O heteroaryl; suitably, Z is selected optionally substituted from C₃-_i0heteroaryl and C1-6 alkyl substituted C₃-_i0 heteroaiyl; suitably, Z is selected from optionally substituted C₃.₉ heteroaryl and C1-6 alkyl substituted C₃.₉ heteroaryl.

More suitably, Z is optionally substituted C₃.₉ heteroaryl or methyl substituted C₃.₉heteroaryl selected from benzofuranylene, benzothiophenylene, indolylene, N-methyl indolylene, N-methylbenzimidazolylene, benzoxazolylene and benzothiazolylene.

More suitably Z is absent and R_i0 is C0₂R”.

More suitably Z is absent and R_i0 is C0₂Ci_6 alkyl.

More suitably D is formula (D7):

Suitably D is of formula (D3) or (D4) and p is o, such that D may be represented by formula (D8) or (D9):

(08)

L 0 (09).

Suitably Ye and Y_g are selected fromNH and CH; NH and N; N-CH₃ and CH; N-CH₃andN; 0 and CH; 0 andN. Suitably Ys and Y_gareN-CH₃ and CH.

Suitably Y10 and Yu are selected from NH and CH; NH andN; N-CH₃ and CH; N-CH₃andN; 0 and CH; and 0 andN. Suitably Y_i0 and Yu are N-CH₃ and CH.

Suitably r is 1 and Y₃ and Y₄ are CH.

Suitably, R₁₀ is H, Z-R” and Z-C0₂R”.

Suitably, R_i0 is Η, Z-H, Z-C1-6 alkyl, Z-C0₂H and Z-C0₂Ci_6 alkyl.

Suitably, Z is selected from optionally substituted C₃-_2O heteroaryl and Ci-6 alkyl substituted C₃._2O heteroaryl; suitably, Z is selected from optionally substituted C₃-_i0heteroaryl and Ci-6 alkyl substituted C₃-i₀ heteroaryl; suitably, Z is selected from optionally substituted C₃__g heteroaryl and Ci-6 alkyl substituted C₃__g heteroaryl.

More suitably, Z is optionally substituted C₃._g heteroaryl or methyl substituted C₃._gheteroaryl selected from benzofuranylene, benzothiophenylene, indolylene, N-methyl indolylene, N-methylbenzimidazolylene, benzoxazolylene and benzothiazolylene.

More suitably Z is absent and R_i0 is C0₂R”.

More suitably Z is absent and R_i0 is C0₂Ci_6 alkyl.

In an embodiment, suitably D is of formula (Di) or (D2) and p is o; r is o; and t is o; such that D may be represented by formula (Dio) or (D11):

or (D11).

Suitably Y_i2 is selected from 0, S, NH andN-CH₃.

Suitably Yi₃ is selected from CH and N;

Suitably, R” is selected from H and Ci-6 alkyl.

Km

Suitably, each R_i4 is independently selected from (CH₂)j-0H, OCH₃, OCH₂CH₃, 0CH₂Ph, (CH₂)NH₂, (CH₂)jNHR, (CH₂)jNRR’, (CH₂)j C0₂R, (CH₂)jC0₂H, 0-(CH₂)_kNR”R”’, C(=0)-NH-(CH₂)_k-NR”R”’, 0(=0)-ΝΗ-0₆Η₄-(0Η₂)_ΓΡ” and C(=0)-NH-(CH₂)_kC(=NH)NR”R”’.

Suitably, each R_i4 is independently selected from (CH₂)j-0H, OCH₃, OCH₂CH₃, 0CH₂Ph, (CH₂)j-C0₂H, (CH₂)j-C0₂CH₃, (CH₂)j-C0₂CH₂CH₃, 0-(CH₂)_k-NH₂, 0-(CH₂)_kNH-CH₃, (CH₂)j-NH₂, (CH₂)j-NH-CH₃, C(=0)-NH-(CH₂)_k-NH₂, C(=0)-NH-(CH₂)_k-NHCH₃, C(=O)-NH-C₆H₄-(CH₂)j-H, C(=0)-NH-(CH₂)_k-C(=NH)NH₂ and C(=O)-NH(CH₂)_k-C(=NH)NH-CH₃.

More suitably, each R₁₄ is independently selected from (CH₂)j-0H, OCH₃, OCH₂CH₃, C0₂H, CO₂CH₃, C0₂CH₂CH₃, 0-(CH₂)_k-NH₂ and (CH₂)j-NH₂.

Suitably, one R_i4 group is selected from 0-(CH₂)_k-NR”R’”, (CH₂)NH₂, (CH₂)jNHR, (CH₂)jNRR’, C(=0)-NH-(CH₂)_k-NR”R”’, C(=O)-NH-C6H₄-(CH₂)j-R” and C(=O)-NH(CH₂)_k-C(=NH)NR”R”’; and the remaining R_i4 groups are each independently selected from (CH₂)j-0H, OCi-e alkyl, 0CH₂Ph, (CH₂)jC0₂H and (CH₂)j-C0₂R.

More suitably, one R_i4 group is selected from 0-(CH₂)_k-NH₂, O-(CH₂)_k-NH-CH₃, (CH₂)j-NH₂, (CH₂)j-NH-CH₃, C(=0)-NH-(CH₂)_k-NH₂, C(=O)-NH-(CH₂)_k-NH-CH₃, C(=O)-NH-C₆H₄-(CH₂)j-H, C(=0)-NH-(CH₂)_k-C(=NH)NH₂ and C(=0)-NH-(CH₂)_kC(=NH)NH-CH₃; and the remaining R_i4 groups are each independently selected from (CH₂)j-0H, methyl, ethyl, OCH₃, OCH₂CH₃, 0CH₂Ph, (CH₂)j-C0₂H, (CH₂)j-C0₂CH₃ and (CH₂)j-C0₂CH₂CH₃.

More suitably, one R_i4 group is selected from 0-(CH₂)_k-NH₂ and (CH₂)j-NH₂; and the remaining R₁₄ groups are each independently selected from (CH₂)j-0H, methyl, ethyl, OCH₃, och₂ch₃, co₂h, co₂ch₃, co₂ch₂ch₃.

R17, Ri6, Rt7, Ri«, Rio and R₂q

Suitably, R_i5, Ri6, Ri₇, Ris, Rig and R₂₀ are independently selected from H, methyl, ethyl, propyl, butyl and R_i4.

Suitably, R_i5, R16, Ri₇, Ris, Rig and R₂₀ are independently selected from H, methyl, ethyl, (CH₂)j-0H, OCH₃, OCH₂CH₃, C0₂H, CO₂CH₃, C0₂CH₂CH₃, 0-(CH₂)_k-NH₂ and (CH₂)jNH₂.

Combination of Substituents

Suitably, at least 3 of Ri to R₇ are H. Suitably, at least 4 of R₂ to R₇ are H.

In one aspect, one of Ri to R₇ is selected from NH₂, NH(Ci-6 alkyl), CO₂(Ci-6 alkyl), CH₂CO₂(Ci-6 alkyl), C0₂H and CH₂-C0₂H; and at least four of the remaining of Ri to R₇ are independently selected from H, C1-6 alkyl and O-C1-6 alkyl.

Suitable structures

In some aspects, the compound of formula (I) has no double bonds in the C-ring and may be represented by the following structure (la):

da).

Suitably, the compound of formula (la) may be prepared with controlled stereochemistry and may be selected from:

	Rs				Rs				Rs
	R^?,	r₉			yc	r₉			AV
Rs	Cj )n	Rs	A	ή )n	Rs,	A
		JAri	J		I		___z*		I	>Ri
Rs	T 'a,,.,.	N	Rs	V		N Γ	Rs	T	J
	r₄ W	1 ^R2		R4	w	y^R₂		r₄	w
		Rs				Rs			Rs
	(lb),				(Ic),				(Id),
	Rs				Rs				Rs
	R₇, Ar^m	r₉		r₇		R₉		?⁷	( zF^N^^Rs
^R6.	ή )n	Re.		1\)n	Re,	A
	O	JXri			J	M'^R1	Ri		1
	X ^A'^w'	/ I £ ^R2	Ri	r₄	^Aw	V-,	I r₄	Rq	Γ^2
		Rs				Rs			1x3
	(Ie),				(Ie),				(If),

In one aspect, the compound of formula (I) has a double bond between Ci and C2 and may be represented by the formula (IX):

Suitably, the compound of formula (IX) may be prepared with controlled

In one aspect, the compound of formula (I) has a double bond between C2 and C3 and may be represented by the formula (X):

Suitably, the compound of formula (X) may be prepared with controlled stereochemistry and may be selected from:

In some aspects, the compound is a compound of formula (I) wherein m is ο, n is 1, A is

C=O and W is absent and maybe represented by formula (IV):

Suitably, the compound of formula (IV) has no double bonds in the C-ring and maybe represented by formula (IVa):

(IVa)

The possible options for stereoisomers of the C-ring for the compound of formula (IVa) are set out above as structures (Ib)-(Ih).

Suitably, the compound of formula (IV) above may have a double bond between Ci and

C2 and may be represented by formula (XI):

The possible options for stereoisomers of the C-ring for the compound of formula (XI) are set out above as structures (IXa)-(IXb).

Suitably, the compound as represented by formula (IV) above may have a double bond between C2 and C3 and maybe represented by formula (XII):

(XII).

The possible options for stereoisomers of the C-ring for the compound of formula (XII) are set out above as structures (Xa)-(Xb).

More suitably the compound of formula (IV) has R3 = R4 = R7 = H and maybe represented by formula (XIII):

In some aspects, the compound is a compound of formula (I) wherein m is 1, n is o, A is

C=0 and W is absent and maybe represented by formula (V):

Suitably, the compound of formula (V) has no double bonds in the C-ring and maybe represented by formula (Va):

The possible options for stereoisomers of the C-ring for the compound of formula (Va) are set out above as structures (Ib)-(Ih).

Suitably, the compound of formula (V) above may have a double bond between Ci and C2 and maybe represented by formula (XIV):

The possible options for stereoisomers of the C-ring for the compound of formula (XIV) are set out above as structures (IXa)-(IXb).

Suitably, the compound as represented by formula (V) above may have a double bond between C2 and C3 and may be represented by formula (XV):

The possible options for stereoisomers of the C-ring for the compound of formula (XV) are set out above as structures (Xa)-(Xb).

More suitably the compound of formula (V) has R3 = R4 = R7 = H and may be represented by the following formula (XVI):

In the most suitable aspects, the compound is a compound of formula (I) wherein m is ο, n is o, A is C=0 and W is CH₂ and may be represented by formula (VI):

(VI).

Suitably, the compound of formula (VI) has no double bonds in the C-ring and maybe represented by formula (Via):

The possible options for stereoisomers of the C-ring for the compound of formula (Via) are set out above as structures (Ib)-(Ih).

Suitably, the compound of formula (VI) above may have a double bond between Ci and

C2 and maybe represented by formula (XVII):

(XVII).

The possible options for stereoisomers of the C-ring for the compound of formula (XVII) are set out above as structures (IXa)-(IXb).

Most suitably, the compound as represented by formula (VI) above may have a double bond between C2 and C3 and may be represented by formula (XVIII):

(XVIII).

More suitably the compound of formula (VI) has R3 = R4 = R7 = H and maybe represented by the following structure (XIX):

In some aspects, the compound is a compound of formula (I) wherein m is ο, n is o, A is CH₂ and W is C=0 and may be represented by formula (VII):

(VII).

Suitably, the compound of formula (VII) has no double bonds in the C-ring and may be represented by formula (Vila):

(Vila)

The possible options for stereoisomers of the C-ring for the compound of formula (Vila) are set out above as structures (Ib)-(Ih).

Suitably, the compound of formula (VII) above may have a double bond between Ci and C2 and may be represented by formula (XX):

(XX).

The possible options for stereoisomers of the C-ring for the compound of formula (XX) are set out above as structures (IXa)-(IXb).

Suitably, the compound as represented by formula (VII) above may have a double bond between C2 and C3 and may be represented by formula (XXI):

(XXI).

The possible options for stereoisomers of the C-ring for the compound of formula (XXI) are set out above as structures (Xa)-(Xb).

More suitably the compound of formula (VII) has R3 = R4 = R7 = H and may be represented by the following structure (XXII):

More suitably, the compound of formula (VII) has the following structure (XXIII):

(XXIII).

Further embodiments

In a further embodiment, the compound of formula (I) has the following structure:

and salts or solvates thereof, wherein:

R₅ is selected from H, C1-12 alkyl, C2-12 alkenyl, OH, 0-Cx-₁₂ alkyl, NH₂, NH(Ci-i₂ alkyl), =0, =CH-Ci-₁₂ alkyl, =CH₂, C0₂H, 0(0)-0-0^ alkyl;

one of A or W is C=0 and the other is CH₂;

and either
(i)	Rs and R_g together form a double bond;
(ii)	Rs is H and R_g is OH; or
(iii)	Rs is H and R_g is 0R^A and R^A is C1-6 alkyl;
and wherein

(a) the compound is a dimer with each monomer being the same or different and being of formula (I) where one of Rx, R₂ and R6 of the first monomer and one of R’i, R’₂ and R’6 of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers;

and the remaining of Ri and R₂ of the first monomer and the remaining of R’i and R’₂ of the second monomer that do not form the bridge are independently selected from H, Cx-₁₂ alkyl, C₂_i₂ alkenyl, OH, 0-Ci_i₂ alkyl, NH₂, NH(Ci_i₂ alkyl), =0, =CH-C₁₁₂ alkyl, =CH₂, C0₂H and C(0)-0-Cx-x₂ alkyl;

and the remaining of R6 of the first monomer and R^ of the second monomer that do not form the bridge are independently selected from H, Cx-₁₂ alkyl, C₂.₁₂alkenyl, OH, 0-Ci-i₂ alkyl, NH₂, NH(Ci-i₂ alkyl), C0₂H and C(0)-0-Ci-i₂ alkyl or (b) one of Ri and R₂ has the formula:

-X-L-X’-D;

and the remaining one of Ri and R₂ is selected H, Cx-x₂ alkyl, C₂-₁₂ alkenyl, OH, 0-C!-₁₂ alkyl, NH₂, NH(Cx-i₂ alkyl), =0, =CH-Cx-i₂ alkyl, =CH₂, C0₂H and C(0)0-Cx-₁₂ alkyl;

and R6 selected from H, C1-12 alkyl, C2-12 alkenyl, OH, O-C1-12 alkyl, NH₂, NH(Ci-i₂alkyl), C0₂H and C(0)-0-Ci_i₂ alkyl;

or (c) R6 has the formula:

-X-L-X’-D;

or is:

-(CH₂)_g-O-Ri₃;

wherein R_i3 is selected from H and Ci-i₂ alkyl; g is 0 or 1;

and Ri and R₂ are independently selected from H, Ci-_i2 alkyl, C₂_i₂ alkenyl, OH, O-Cx-x;, alkyl, NH₂, ΝΗ(0χ-₁₂ alkyl), =0, =CH-C₁-₁₂ alkyl, =CH₂, C0₂H and C(0)O-Ci-12 alkyl;

and wherein:

X is selected from 0, =CH-, C(=O)NH and NHC(=O);

L is selected from a peptide chain having from 2 to 5 amino acids; an alkylene chain containing from 1 to 11 carbon atoms which may contain one or more carbon-carbon double or triple bonds; -(0CH₂)i-i2- and -(OCH₂CH₂)i_₅-;

X’ is selected 0, =CH-, C(=O)NH and NHC(=O) or is absent;

D is selected from formula (Di):

formula (D2):

O (D2);

formula (D3):

(d₃);

and formula (D4):

Y (04);

p is 0 or 1;

qis 1, 2, 3, 4, 5 or 6;

r is 0 or 1;

t is 0 or 1

Y, Yi and Y₂ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and NCH₃; N, N-CH₃ and CH; CH, S and CH; CH, CH and S; N, S and CH; N, CH and S; N, 0 and CH; N, CH and O; CH, CH and O; CH 0 and CH; COH, N-CH₃ and CH; and COH, CH andN-CH₃;

Y₃ is N or CH;

Y₄ is N or CH; wherein at least one of Y₃ and Y₄ is CH;

Y₅, Υβ and Y₇ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and NCH₃; N, N-CH₃ and CH; CH, S and CH; CH, CH and S; N, S and CH; N, CH and S; N, 0 and CH; N, CH and O; CH, CH and O; CH 0 and CH; COH, N-CH₃ and CH; and COH, CH andN-CH₃;

Ye is selected from 0, S, NH and N-CH₃;

Y_gis selected from CH and N;

Y10 is selected from 0, S, NH and N-CH₃;

Yu is selected from CH and N;

Z is absent or is selected from benzofuranylene, benzothiophenylene, indolylene, Nmethyl indolylene, N-methylbenzimidazolylene, benzoxazolylene and benzothiazolylene; and

R” and R’” are independently selected from H, and C1-12 alkyl.

or is a dimer with the following structure:

and salts or solvates thereof, wherein:

Ri, R₂, R’i and R’₂ are independently selected from H, Ci-_i2 alkyl, C₂._i2 alkenyl, OH, O-Ci₁₂ alkyl, NH₂, NHCC^ alkyl), =0, =CH-C₁-₁₂ alkyl, =CH₂, C0₂H, 0(0)-0-0^ alkyl;

R₅ and R’₅ are independently selected from H, Ci-_i2 alkyl, O-Ci-6 alkyl and 0CH₂Ph;

R6 has the formula:

-X-L-X’-D;

or is:

-(CH₂)_g-O-Ri₃;

wherein R_i3 is selected from H and Ci-_i2 alkyl; g is o or 1;

and either:

(i) Rs and R_g together form a double bond, and R’s and R’_g together form a double bond;

(ii) Rs is H and R_g is OH, and R’s is H and R’_g is OH; or (iii) Rs is H and R_g is O-Ci-6 alkyl, and R’s is H and R’_g is O-Ci-6 alkyl; and and wherein:

X is selected from 0, =CH-, C(=0)NH and NHC(=0);

L is selected from a peptide chain having from 2 to 5 amino acids; an alkylene chain containing from 1 to 11 carbon atoms which may contain one or more carbon-carbon double or triple bonds; -(0CH₂)i-_i2- and -(OCH₂CH₂)i_₅-;

X’ is selected 0, =CH-, C(=0)NH and NHC(=0) or is absent;

D is:

or

wherein:

qis 1, 2, 3, 4, 5 or 6;

r is o or 1;

t is o or 1

Y, X and Y₂ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH;

Y₃ is N or CH;

Y₄ is N or CH; wherein at least one of Y₃ and Y₄ is CH;

Y₅, Y₆ and Y₇ are selected from CH, CH and N-CH₃; CH, N-CH₃ and CH; N, CH and N-CH₃; N, N-CH₃ and CH;

R₁₀ is Η, Z-H, Z-Ci-e alkyl, Z-C0₂H and Z-CO^-e alkyl; and

Z is absent or is selected from benzofuranylene, benzothiophenylene, indolylene, N-methyl indolylene, N-methylbenzimidazolylene, benzoxazolylene and benzothiazolylene.

Monomeric compounds

wherein q is selected from 1, 2, 3, 4, 5 and 6; L is an alkylene chain containing from 1 to 12 carbon atoms; Y, Yi and Y₂ are CH, N-CH₃ and CH; or are N, N-CH₃ and CH respectively; Y_i2 is selected from 0, S, NH and N-CH₃; Y_i3 is selected from CH and N; and R” is selected from H and C1-6 alkyl.

The possible options for the presence or absence of double bonds in the C-ring and for stereoisomers of the above compound are set out above as structures Ib-Ih and IX-Xb in the suitable structures section.

Suitably the compound of formula (I) is:

wherein q is selected from 1, 2, 3, 4, 5 and 6; Y is CH or N; and Y_i2 is S or 0.

Dimer

In an embodiment (a) the compound is a dimer with each monomer being the same or different and being of formula (I) where one of Ri, R₂ and R6 of the first monomer and R’i, R’₂ and R’6 of the second monomer form together a bridge having the formula -XL-X’- linking the monomers.

Where a dimer is formed from two monomers of formula (I) and the Ri group of the first monomer and the R’i of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (Al):

Where a dimer is formed from two monomers of formula (I) and the Ri group of the first monomer and the R’₂ of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A2):

r₃ (A2)

Where a dimer is formed from two monomers of formula (I) and the Ri group of the first monomer and the R’6 of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A3):

Where a dimer is formed from two monomers of formula (I) and the R₂ group of the first monomer and the R\ of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A4):

Where a dimer is formed from two monomers of formula (I) and the R₂ group of the first monomer and the R’₂ of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A5):

Where a dimer is formed from two monomers of formula (I) and the R₂ group of the first monomer and the R’6 of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A6):

Where a dimer is formed from two monomers of formula (I) and the R6 group of the first monomer and the R’i of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A7):

Where a dimer is formed from two monomers of formula (I) and the R6 group of the first monomer and the R’₂ of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer maybe represented by the following formula (A8):

Where a dimer is formed from two monomers of formula (I) and the R6 groups of the monomers form together a bridge having the formula -X-L-X’- linking the monomers, the resulting dimer may be represented by the following formula (A9):

The possible options for the presence or absence of double bonds in the C-ring and for stereoisomers of each monomer are set out above in the suitable structures section.

Wherein for each of formulas (Al), (A2), (A3), (A4), (A5), (A6), (A7), (A8) and (A9) the groups A’, W, X’, m’, n’, R’₃, R’₄, R’₅, R’₇, R’s and R’_g are independently selected from groups with the same meanings as for A, W, m, η, X, R₃, R₄, R₅, R₇, Rg and R_grespectively, and L is as described above.

For each of formulas (A4), (A5), (A6), (A7), (A8) and (A9the remaining substituent Ri is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂-C0₂R, CH₂-C0₂H, CH₂-S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Ci-₁₂ alkylene)-C(O)NR”,R’” and (C₂-_i2 alkenylene)-C(O)NR’R” and halo. Suitably the remaining substituents Ri is selected from H, R, OR, NH₂, NHR, NRR’,CH₂-0R, =0, =CH-R, =CH₂, CH₂-C0₂R, C0₂H, C0₂R, COR, (C!-₁₂ alkylene)-C(O)NR”,R’” and (C₂_₁₂ alkenylene)-C(O)NR’R” and halo.

For each of formulas (A2), (A3), (A5), (A6), (A8) and (A9) the remaining substituent R’i is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂

C0₂R, CH₂-C0₂H, CH₂-S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Cx-₁₂ alkylene)C(O)NR”,R”’ and (C₂-_i2 alkenylene)-C(O)NR’R” and halo. Suitably the remaining substituents R’i is selected from H, R, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂-C0₂R, C0₂H, C0₂R, COR, Cx-₁₂ alkylene)-C(O)NR”,R’” and (C₂_₁₂alkenylene)-C(O)NR’R” and halo.

For each of formulas (Al), (A2), (A3), (A7), (A8) and (A9) the remaining substituent R₂is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂C0₂R, CH₂-C0₂H, CH₂-S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Cx-₁₂ alkylene)C(O)NR”,R’” and (C₂.₁₂ alkenylene)-C(O)NR’R” and halo. Suitably the remaining substituents R₂is selected from H, R, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂-C0₂R, C0₂H, C0₂R, COR, (Cx-₁₂ alkylene)-C(O)NR”,R’” and (C₂.₁₂alkenylene)-C(O)NR’R” and halo.

For each of formulas (Al), (A3), (A4), (A6), (A7) and (A9) the remaining substituent R’₂ is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂C0₂R, CH₂-C0₂H, CH₂-S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Cx-12 alkylene)C(O)NR”,R’” and (C₂-x₂ alkenylene)-C(O)NR’R” and halo. Suitably the remaining substituents R’₂ is selected from H, R, OR, NH₂, NHR, NRR’, CH₂-0R, =0, =CH-R, =CH₂, CH₂-C0₂R, C0₂H, C0₂R, COR, NR”R’”, (Cx-12 alkylene)-C(O)NR”,R’” and (C₂-x₂alkenylene)-C(O)NR’R” and halo.

For each of formulas (Al), (A2), (A3), (A4), (A5) and (A6) the remaining substituent R6 is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, CH₂-C0₂R, CH₂-C0₂H, CH₂S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Ci-12 alkylene)-C(O)NR”,R’” and (C₂-x₂alkenylene)-C(O)NR’R” and halo. Suitably R6 is selected from H, Ci-_i2 alkyl, OH, 0-Ci-_i2alkyl, 0CH₂Ph, NH₂, NH(Ci-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(Ci-₆ alkyl), CH₂-CO₂(Ci-₆alkyl) and halo. More suitably R6 is selected from H, O-C1-6 alkyl, 0CH₂Ph, NH₂, NH(Cx-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(C₁.₆ alkyl) and CH₂-C0₂(Cx-₆ alkyl)..

For each of formulas (Al), (A2), (A4), (A5), (A7) and (A8) the remaining substituent R’e is selected from H, R, OH, OR, NH₂, NHR, NRR’, CH₂-0R, CH₂-C0₂R, CH₂-C0₂H, CH₂-S0₂R, 0-S0₂R, C0₂H, C0₂R, COR, CN, (Cx-12 alkylene)-C(O)NR”,R’” and (C₂-i₂alkenylene)-C(O)NR’R” and halo. Suitably R’6 is selected from H, Ci-_i2 alkyl, OH, O-Ci12 alkyl, 0CH₂Ph, NH₂, NH(Ci-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(Ci-₆ alkyl), CH₂-CO₂(Ci-₆alkyl) and halo. More suitably R’6 is selected from H, O-C1-6 alkyl, 0CH₂Ph, NH₂, NH(Ci-₆ alkyl), C0₂H, CH₂-C0₂H, CO₂(Cx-₆ alkyl) and CH₂-CO₂(Ci-₆ alkyl).

More suitably the compound of formula (I) is a dimer selected from the formulas (Al), (A5) and (A9).

More suitably the compound of formula (I) is a dimer with each monomer being the same and being of formula (I).

More suitably the compound of formula (I) is a dimer with each monomer being the same and being of formula (I) where the Re groups of the monomers form together a bridge having the formula -X-L-X’- linking the monomers.

More suitably, the dimer may be represented by formula (A10):

More suitably, the dimer may be represented by formula (An):

More suitably, the dimer maybe represented by formula (A12):

and either:

(ii) Rs is H and R_g is OH, and R’s is H and R’_g is OH; or (iii) Rs is H and R_g is O-C1-6 alkyl, and R’s is H and R’_g is O-C1-6 alkyl.

More suitably, the dimer has the structure:

and either:

(ii) Rs is H and R_g is OH, and R’s is H and R’_g is OH; or (iii) Rs is H and R_g is O-Ci-6 alkyl, and R’s is H and R’_g is O-Ci-6 alkyl.

Most suitably, the dimer has the structure:

and either:

Applications

The invention finds application in the treatment of proliferative diseases.

In certain aspects a method of treating a proliferative disease is provided, the method comprising administering to a subject a therapeutically effective amount of a compound of the formula (I) and salts or solvates thereof or a composition comprising a compound of formula (I) and salts or solvates thereof.

In certain aspects a method of treating a proliferative disease is provided, the method comprising administering to a subject a therapeutically effective amount of a targeted conjugate comprising a compound of the formula (I) and salts or solvates thereof.

In certain aspects a method of treating a proliferative disease is provided, the method comprising administering to a subject a therapeutically effective amount of an antibody-drug conjugate comprising a compound of the formula (I) and salts or solvates thereof.

In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (a) where the compound of formula (I) is a dimer. In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiments (b) or (c) where the compound of formula (I) is a monomer.

The term “proliferative disease” refers to an unwanted or uncontrolled cellular proliferation of excessive or abnormal cells which is undesired, such as, neoplastic or hyperplastic growth, whether in vitro or in vivo. Examples of proliferative conditions include, but are not limited to, benign, pre-malignant, and malignant cellular proliferation, including but not limited to, neoplasms and tumours (e.g. histocytoma, glioma, astrocyoma, osteoma), cancers (e.g. lung cancer, small cell lung cancer, hepatocellular cancer, gastric or stomach cancer including gastrointestinal cancer, bowel cancer, colon cancer, hepatoma, breast cancer, glioblastoma, cervical cancer, ovarian cancer, prostate cancer, testicular cancer, liver cancer, rectal cancer, colorectal cancer, endometrial or uterine carcinoma, salivary gland carcinoma, kidney or renal cancer, prostate cancer, vulval cancer, thyroid cancer, hepatic carcinoma, anal carcinoma, penile carcinoma, head and neck cancer, bladder cancer, pancreas cancer, brain cancer, sarcoma, osteosarcoma, Kaposi’s sarcoma, melanoma), leukemias, psoriasis, bone diseases, fibroproliferative disorders (e.g. of connective tissues), and atherosclerosis. Cancers of particular interest include, but are not limited to, breast cancer (both ER positive and ER negative), pancreatic cancer, lung cancer and leukaemia.

Any type of cell may be treated, including but not limited to, lung, gastrointestinal (including, e.g. bowel, colon), breast (mammary), ovarian, prostate, liver (hepatic), kidney (renal), bladder, pancreas, brain, and skin.

A skilled person is readily able to determine whether or not a candidate compound treats a proliferative condition for any particular cell type.

Suitably subjects are human, livestock animals and companion animals.

Suitably, a compound of formula (I) and salts or solvates thereof, for use as a drug in targeted conjugate is prepared by attaching a compound of formula (I) and salts or solvates thereof to a targeting agent, either directly or via an optional linker group. Suitably, the compound of formula (I) and salts or solvates thereof, is attached to a targeting agent via a linker group. Suitably, the targeted conjugate is for use in the treatment of a disease, more specifically of a proliferative disease. Suitably, the drug may be attached by any suitable functional group that it contains to the targeting agent either directly or via a linker group. Typically, the drug contains, or can be modified to contain, one or more functional groups such as amine, hydroxyl or carboxylic acid groups for attaching the drug to the targeting agent either directly or via a linker group. In some aspects, one or more atoms or groups of the compound of formula (I) may be eliminated during the attachment of the drug to the antibody. In some aspects, the targeting agent binds to a cell surface receptor or a tumor-associated antigen. In some aspects, the targeting agent is an antibody. In some aspects, the targeting agent is a hormone. In some aspects, the targeting agent is a protein. In some aspects, the targeting agent is a polypeptide. In some aspects, the targeting agent is a small molecule (for example, folic acid).

In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (a). In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (b). In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (c). In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (a) where the compound of formula (I) is a dimer. In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiments (b) or (c) where the compound of formula (I) is a monomer.

Antibody Drug Conjugates

Antibody therapy has been established for the targeted treatment of patients with cancer, immunological and angiogenic disorders (Carter, P. (2006) Nature Reviews Immunology 6:343-357). The use of antibody-drug conjugates (ADC), i.e. immunoconjugates, for the local delivery of cytotoxic or cytostatic agents, i.e. drugs to kill or inhibit tumor cells in the treatment of cancer, targets delivery of the drug moiety to tumors, and intracellular accumulation therein, whereas systemic administration of these unconjugated drug agents may result in unacceptable levels of toxicity to normal cells (Xie et al (2006) Expert. Opin. Biol. Ther. 6(3):281 -291; Kovtun ef a/ (2006) Cancer Res. 66(6):3214-3121; Law et al (2006) CancerRes. 66(4):2328-23375 Wu et al (2005) Nature Biotech. 23(9): 1137-1145; Lambert J. (2005) Current Opin. in Pharmacol. 5:543-549; Hamann P. (2005) Expert Opin. Ther. Patents 15(9): 1087-1 103; Payne, G. (2003) Cancer Cell 3:207-212; Trail ef a/ (2003) Cancer Immunol. Immunother. 52:328-337; Syrigos and Epenetos (1999) Anticancer Research 19:605614).

Maximal efficacy with minimal toxicity is sought thereby. Efforts to design and refine ADC have focused on the selectivity of monoclonal antibodies (mAbs) as well as drug mechanism of action, drug-linking, drug/antibody ratio (loading), and drug-releasing properties (Junutula, et al., 2008b Nature Biotech., 26(8):925-9325 Doman et al., (2009) Blood 114(13):2721 -2729; US 7521541; US 7723485; WO2OO9/O52249; McDonagh (2006) Protein Eng. Design & Sei. 19(7): 299-307; Doronina et al., (2006) Bioconj. Chem. 17:114-124; Erickson et al., (2006) CancerRes. 66(8): 1-8; et al., (2005) Clin. CancerRes. 11:843-8525 Jeffrey et al., (2005) J. Med. Chem. 48:1344-1358; Hamblett et al., (2004) Clin. Cancer Res. 10:7063- 7070).

In some aspects, the present invention relates to a compound of formula (I) and salts or solvates thereof, for use as a drug in an antibody-drug conjugate. Suitably, a compound of formula (I) and salts or solvates thereof, for use as a drug in an antibody-drug conjugate is prepared by attaching a compound of formula (I) and salts or solvate thereof to an antibody, either directly or via an optional linker group. Suitably, the compound of formula (I) and salts or solvates thereof, is attached to an antibody via a linker group. Suitably, the antibody-drug conjugate is for use in for treatment of a disease, more specifically of a proliferative disease. Suitably, the antibody-drug conjugate is for use in for treatment of a disease, more specifically of a proliferative disease. Suitably, the drug may be attached by any suitable functional group that it contains to the antibody either directly or via a linker group. Typically, the drug contains, or can be modified to contain, one or more functional groups such as amine, hydroxyl or carboxylic acid groups for attaching the drug to the antibody either directly or via a linker group. In some aspects, the antibody of the antibody drug conjugate is an antibody fragment, such as, but not limited to a single chain antibody. In some aspects, one or more atoms or groups of the compound of formula (I) maybe eliminated during the attachment of the drug to the antibody. In some aspects, the antibody binds to a cell surface receptor or a tumor-associated antigen.

In some aspects, the present invention relates to the use of a compound of formula (I) and salts or solvates thereof, as a drug in an antibody-drug conjugate. Suitably, the use of a compound of formula (I) and salts or solvates thereof, as a drug in an antibodydrug conjugate is accomplished by attaching a compound of formula (I) and salts or solvates thereof to an antibody, either directly or via an optional linker group. Suitably, the compound of formula (I) and salts or solvates thereof, is attached to an antibody via a linker group. Suitably, the antibody-drug conjugate is for use in for treatment of a disease, more specifically of a proliferative disease. Suitably, the drug may be attached by any suitable functional group that it contains to the antibody either directly or via a linker group. Typically, the drug contains, or can be modified to contain, one or more functional groups such as amine, hydroxyl or carboxylic acid groups for attaching the drug to the antibody either directly or via a linker group. In some aspects, the antibody of the antibody drug conjugate is an antibody fragment, such as, but not limited to a single chain antibody. In some aspects, one or more atoms or groups of the compound of formula (I) may be eliminated during the attachment of the drug to the antibody. In some aspects, the antibody binds to a cell surface receptor or a tumor-associated antigen.

In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (a). In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiments (b) and (c). In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (a) where the compound of formula (I) is a dimer. In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (b) where the compound of formula (I) is a monomer. In certain aspects, the compound of the formula (I) and salts or solvates thereof is a compound according to embodiment (c) where the compound of formula (I) is a monomer.

The substituent groups of the compounds of formula (I) may interact with DNA sequences and may be selected so as to target specific sequences.

Antibody and antibody fragments

The term “antibody” specifically covers monoclonal antibodies, polyclonal antibodies, dimers, multimers, multispecific antibodies (e.g., bispecific antibodies), intact antibodies and antibody fragments, so long as they exhibit the desired biological activity, for example, the ability to bind a desired antigen on a target cell or tissue. Antibodies may be murine, human, humanized, chimeric, or derived from other species. An antibody is a protein generated by the immune system that is capable of recognizing and binding to a specific antigen. (Janeway, C, Travers, P., Walport, M., Shlomchik (2001) Immuno Biology, 5th Ed., Garland Publishing, New York). A target antigen generally has numerous binding sites, also called epitopes, recognized by CDRs on the antibody. Each antibody that specifically binds to a different epitope has a different structure. Thus, one antigen may have more than one corresponding antibody. An antibody includes a full-length immunoglobulin molecule or an immunologically active portion of a full-length immunoglobulin molecule, i.e., a molecule that contains an antigen binding site that immunospecifically binds an antigen of a target of interest or part thereof, such targets including but not limited to, cancer cell or cells that produce autoimmune antibodies associated with an autoimmune disease. The immunoglobulin can be of any type (e.g. IgG, IgE, IgM, IgD, and IgA), class (e.g. IgGi, lgG2, lgG3, lgG4, IgAi and lgA2) or subclass, or allotype (e.g. human Gi mi, Gi m2, Gi m3, non-Gi mi [that, is any allotype other than Gi mi], Gi mi7, G2m23, G3m2i, G311128, G3mi 1, G31115, G311113, G311114, G3mio, G311115, G311116, G31116, G311124, G311126, G311127, A2mi, A2m2, Kmi, Km2 and Km3) of immunoglobulin molecule. The immunoglobulins can be derived from any species, including human, murine, or rabbit origin.

As used herein, “binds an epitope” is used to mean the antibody binds an epitope with a higher affinity than a non-specific partner such as Bovine Serum Albumin (BSA, Genbank accession no. CAA76847, version no. CAA76847.1 Gl:3336842, record update date: Jan 7, 201102:30 PM). In some embodiments the antibody binds an epitope with an association constant (Ka) at least 2, 3, 4,5,10, 20,50,100, 200,500,1000,

2000, 5000? ίο⁴,105 or io⁶-fold higher than the antibody's association constant for BSA, when measured at physiological conditions.

The term “antibody fragment” refers to a portion of a full length antibody, for example, the antigen binding or variable region thereof. Examples of antibody fragments include Fab, Fab', F(ab')2, and scFv fragments; diabodies; linear antibodies; fragments produced by a Fab expression library, anti-idiotypic (anti-Id) antibodies, CDR (complementary determining region), single-chain antibody molecules; and multispecific antibodies formed from antibody fragments and epitope-binding fragments of any of the above which immunospecifically bind to target antigens, such as, for example, cancer cell antigens, viral antigens or microbial antigens,. The term “monoclonal antibody” as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e. the individual antibodies comprising the population are identical except for possible naturally occurring mutations that maybe present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to polyclonal antibody preparations which include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant or epitope on the antigen. In addition to their specificity, the monoclonal antibodies are advantageous in that they may be synthesized uncontaminated by other antibodies. The modifier “monoclonal” indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies to be used in accordance with the present invention may be made by the hybridoma method first described by Kohler et al (1975) Nature 256:495, or may be made by recombinant DNA methods (see, US 4816567). The monoclonal antibodies may also be isolated from phage antibody libraries using the techniques described in Clackson et al (1991) Nature, 352:624-628; Marks et al (1991) J. Mol. Biol., 222:581-597 or from transgenic mice carrying a fully human immunoglobulin system (Lonberg (2008) Curr. Opinion 20(4):450-459).

The antibodies, including monoclonal antibodies, herein specifically include “chimeric” antibodies in which a portion of the antibody structure, for example the heavy and/or light chain, is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (US 4816567; and Morrison et al (1984) Proc. Natl. Acad. Sci. USA, 81:6851 -6855). Chimeric antibodies include “primatized” antibodies comprising variable domain antigen-binding sequences derived from a non- human primate (e.g. Old World Monkey or Ape) and human constant region sequences. An “intact antibody” herein is one comprising VL and VH domains, as well as a light chain constant domain (CL) and heavy chain constant domains, CH1, CH2 and CH3. The constant domains may be native sequence constant domains (e.g. human native sequence constant domains) or amino acid sequence variant thereof. The intact antibody may have one or more “effector functions” which refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody. Examples of antibody effector functions include Ci q binding; complement dependent cytotoxicity; Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; and down regulation of cell surface receptors such as B cell receptor and BCR.

The antibodies disclosed herein may be modified. For example, to make them less immunogenic to a human subject. This may be achieved using any of a number of techniques familiar to the person skilled in the art, such as humanisation.

Administration & Dose

Compounds of formula I may be administered alone or in combination with one or another or with one or more pharmacologically active compounds which are different from the compounds of formula I.

Compounds of the invention may suitably be combined with various components to produce compositions of the invention. Suitably the compositions are combined with a pharmaceutically acceptable carrier or diluent to produce a pharmaceutical composition (which maybe for human or animal use). Suitable carriers and diluents include isotonic saline solutions, for example phosphate-buffered saline. Useful pharmaceutical compositions and methods for their preparation may be found in standard pharmaceutical texts. See, for example, Handbook for Pharmaceutical Additives, 3rd Edition (eds. M. Ash and I. Ash), 2007 (Synapse Information Resources, Inc., Endicott, New York, USA) and Remington: The Science and Practice of Pharmacy, 21st Edition (ed. D. B. Troy) 2006 (Lippincott, Williams and Wilkins, Philadelphia, USA) which are incorporated herein by reference.

The compounds of the invention may be administered by any suitable route. Suitably the compounds of the invention will normally be administered orally or by any parenteral route, in the form of pharmaceutical preparations comprising the active ingredient, optionally in the form of a non-toxic organic, or inorganic, acid, or base, addition salt, in a pharmaceutically acceptable dosage form.

The compounds of the invention, their pharmaceutically acceptable salts, and pharmaceutically acceptable solvates of either entity can be administered alone but will generally be administered in admixture with a suitable pharmaceutical excipient diluent or carrier selected with regard to the intended route of administration and standard pharmaceutical practice.

For example, the compounds of the invention or salts or solvates thereof can be administered orally, buccally or sublingually in the form of tablets, capsules (including soft gel capsules), ovules, elixirs, solutions or suspensions, which may contain flavouring or colouring agents, for immediate-, delayed-, modified-, sustained-, controlled-release or pulsatile delivery applications. The compounds of the invention may also be administered via fast dispersing or fast dissolving dosages forms.

Such tablets may contain excipients such as microcrystalline cellulose, lactose, sodium citrate, calcium carbonate, dibasic calcium phosphate and glycine, disintegrants such as starch (preferably corn, potato or tapioca starch), sodium starch glycollate, croscarmellose sodium and certain complex silicates, and granulation binders such as polyvinylpyrrolidone, hydroxypropylmethyl cellulose (HPMC), hydroxypropylcellulose (HPC), sucrose, gelatin and acacia. Additionally, lubricating agents such as magnesium stearate, stearic acid, glyceryl behenate and talc may be included.

Solid compositions of a similar type may also be employed as fillers in gelatin capsules. Preferred excipients in this regard include lactose, starch, a cellulose, milk sugar or high molecular weight polyethylene glycols. For aqueous suspensions and/or elixirs, the compounds of the invention may be combined with various sweetening or flavouring agents, colouring matter or dyes, with emulsifying and/or suspending agents and with diluents such as water, ethanol, propylene glycol and glycerin, and combinations thereof.

Modified release and pulsatile release dosage forms may contain excipients such as those detailed for immediate release dosage forms together with additional excipients that act as release rate modifiers, these being coated on and/or included in the body of the device. Release rate modifiers include, but are not exclusively limited to, hydroxypropylmethyl cellulose, methyl cellulose, sodium carboxymethylcellulose, ethyl cellulose, cellulose acetate, polyethylene oxide, Xanthan gum, Carbomer, ammonio methacrylate copolymer, hydrogenated castor oil, carnauba wax, paraffin wax, cellulose acetate phthalate, hydroxypropylmethyl cellulose phthalate, methacrylic acid copolymer and mixtures thereof. Modified release and pulsatile release dosage forms may contain one or a combination of release rate modifying excipients. Release rate modifying excipients maybe present both within the dosage form i.e. within the matrix, and/or on the dosage form i.e. upon the surface or coating.

Fast dispersing or dissolving dosage formulations (FDDFs) may contain the following ingredients: aspartame, acesulfame potassium, citric acid, croscarmellose sodium, crospovidone, diascorbic acid, ethyl acrylate, ethyl cellulose, gelatin, hydroxypropylmethyl cellulose, magnesium stearate, mannitol, methyl methaciylate, mint flavouring, polyethylene glycol, fumed silica, silicon dioxide, sodium starch glycolate, sodium stearyl fumarate, sorbitol, xylitol.

The compounds of the invention can also be administered parenterally, for example, intravenously, intra-arterially, or they may be administered by infusion techniques. For such parenteral administration they are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic with blood. The aqueous solutions should be suitably buffered (preferably to a pH of from 3 to 9), if necessary. The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques well-known to those skilled in the art.

Suitably formulation of the invention is optimised for the route of administration e.g. oral, intravenously, etc.

Administration may be in one dose, continuously or intermittently (e.g. in divided doses at appropriate intervals) during the course of treatment. Methods of determining the most effective means and dosage are well known to a skilled person and will vary with the formulation used for therapy, the purpose of the therapy, the target cell(s) being treated, and the subject being treated. Single or multiple administrations can be carried out with the dose level and the dose regimen being selected by the treating physician, veterinarian, or clinician.

Depending upon the disorder and patient to be treated, as well as the route of administration, the compositions maybe administered at varying doses. For example, a typical dosage for an adult human may be 100 ng to 25 mg (suitably about 1 micro g to about 10 mg) per kg body weight of the subject per day.

Suitably guidance may be taken from studies in test animals when estimating an initial dose for human subjects. For example when a particular dose is identified for mice, suitably an initial test dose for humans may be approx. 0.5X to 2x the mg/Kg value given to mice.

Other Forms

Unless otherwise specified, included in the above are the well known ionic, salt, solvate, and protected forms of these substituents. For example, a reference to carboxylic acid (-C00H) also includes the anionic (carboxylate) form (-C00 ), a salt or solvate thereof, as well as conventional protected forms. Similarly, a reference to an amino group includes the protonated form (-N⁺H R‘R²), a salt or solvate of the amino group, for example, a hydrochloride salt, as well as conventional protected forms of an amino group. Similarly, a reference to a hydroxyl group also includes the anionic form (-0 ), a salt or solvate thereof, as well as conventional protected forms.

Isomers, Salts and Solvates

Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diasteriomeric, epimeric, atropic, stereoisomeric, tautomeric, conformational, or anomeric forms, including but not limited to, cis- and trans-forms; E- and Z-forms; c-, t-, and r- forms; endo- and exo-forms; R-, S-, and meso-forms; Dand L-forms; d- and 1- forms; (+) and (-) forms; keto-, enol-, and enolate-forms; synand anti-forms; synclinal- and anticlinal-forms; alpha- and beta-forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as “isomers” (or “isomeric forms”).

Note that, except as discussed below for tautomeric forms, specifically excluded from the term “isomers”, as used herein, are structural (or constitutional) isomers (i.e. isomers which differ in the connections between atoms rather than merely by the position of atoms in space). For example, a reference to a methoxy group, -OCH₃, is not to be construed as a reference to its structural isomer, a hydroxymethyl group, CH₂0H.

A reference to a class of structures may well include structurally isomeric forms falling within that class (e.g. Ci-₇ alkyl includes n-propyl and iso-propyl; butyl includes η-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl).

The above exclusion does not apply to tautomeric forms, for example, keto-, enol-, and enolate-forms, as in, for example, the following tautomeric pairs: keto/enol, imine/enamine, amide/imino alcohol, amidine/amidine, nitroso/oxime, thioketone/enethiol, N-nitroso/hyroxyazo, and nitro/aci-nitro.

Note that specifically included in the term “isomer” are compounds with one or more isotopic substitutions. For example, H may be in any isotopic form, including Ή, ²H (D), and ³H (T); C may be in any isotopic form, including ¹²C, ¹³C, and ¹⁴C; 0 may be in any isotopic form, including ¹⁶0 and ¹⁸0; and the like.

Unless otherwise specified, a reference to a particular compound includes all such isomeric forms, including (wholly or partially) racemic and other mixtures thereof.

Methods for the preparation (e.g. asymmetric synthesis) and separation (e.g. fractional crystallisation and chromatographic means) of such isomeric forms are either known in the art or are readily obtained by adapting the methods taught herein, or known methods, in a known manner.

Unless otherwise specified, a reference to a particular compound also includes ionic, salt, solvate, and protected forms of thereof, for example, as discussed below.

Compounds of Formula 1, which include compounds specifically named above, may form pharmaceutically acceptable complexes, salts, solvates and hydrates. These salts include nontoxic acid addition salts (including di-acids) and base salts.

If the compound is cationic, or has a functional group which maybe cationic (e.g. -NH₂may be -NH₃ ⁺), then an acid addition salt may be formed with a suitable anion. Examples of suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids hydrochloric acid, nitric acid, nitrous acid, phosphoric acid, sulfuric acid, sulphurous acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, phosphoric acid and phosphorous acids. Examples of suitable organic anions include, but are not limited to, those derived from the following organic acids: 2-acetyoxybenzoic, acetic, ascorbic, aspartic, benzoic, camphorsulfonic, cinnamic, citric, edetic, ethanedisulfonic, ethanesulfonic, fumaric, glucheptonic, gluconic, glutamic, glycolic, hydroxymaleic, hydroxynaphthalene carboxylic, isethionic, lactic, lactobionic, lauric, maleic, malic, methanesulfonic, mucic, oleic, oxalic, palmitic, pamoic, pantothenic, phenylacetic, phenylsulfonic, propionic, pyruvic, salicylic, stearic, succinic, sulfanilic, tartaric, toluenesulfonic, and valeric. Examples of suitable polymeric organic anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl cellulose. Such salts include acetate, adipate, aspartate, benzoate, besylate, bicarbonate, carbonate, bisulfate, sulfate, borate, camsylate, citrate, cyclamate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobro mi de/bromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methylsulfonate, naphthylate, 2napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate, hydrogen phosphate, dihydrogen phosphate, pyroglutamate, saccharate, stearate, succinate, tannate, tartrate, tosylate, trifluoroacetate and xinofoate salts.

For example, if the compound is anionic, or has a functional group which may be anionic (e.g. -COOH may be -COO ), then a base salt may be formed with a suitable cation. Examples of suitable inorganic cations include, but are not limited to, metal cations, such as an alkali or alkaline earth metal cation, ammonium and substituted ammonium cations, as well as amines. Examples of suitable metal cations include sodium (Na⁺) potassium (K⁺), magnesium (Mg²⁺), calcium (Ca²⁺), zinc (Zn²⁺), and aluminum (Al³⁺). Examples of suitable organic cations include, but are not limited to, ammonium ion (i.e. NH4⁺) and substituted ammonium ions (e.g. NH3R⁺, NH2R₂ ⁺, NHR3⁺, NRv). Examples of some suitable substituted ammonium ions are those derived from: ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine. An example of a common quaternary ammonium ion is N(CH3)₄ ⁺. Examples of suitable amines include arginine, N,N'dibenzylethylenediamine, chloroprocaine, choline, diethylamine, diethanolamine, dicyclohexylamine, ethylenediamine, glycine, lysine, N-methylglucamine, olamine, 2amino-2-hydroxymethyl-propane-i,3-diol, and procaine. For a discussion of useful acid addition and base salts, see S. M. Berge et al., J. Pharm. Sci. (1977) 66:1-19; see also Stahl and Wermuth, Handbook of Pharmaceutical Salts: Properties, Selection, and Use (2011)

Pharmaceutically acceptable salts may be prepared using various methods. For example, one may react a compound of Formula 1 with an appropriate acid or base to give the desired salt. One may also react a precursor of the compound of Formula 1 with an acid or base to remove an acid- or base-labile protecting group or to open a lactone or lactam group of the precursor. Additionally, one may convert a salt of the compound of Formula 1 to another salt through treatment with an appropriate acid or base or through contact with an ion exchange resin. Following reaction, one may then isolate the salt by filtration if it precipitates from solution, or by evaporation to recover the salt. The degree of ionization of the salt may vary from completely ionized to almost non-ionized.

It maybe convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the active compound. The term “solvate” describes a molecular complex comprising the compound and one or more pharmaceutically acceptable solvent molecules (e.g., EtOH). The term “hydrate” is a solvate in which the solvent is water. Pharmaceutically acceptable solvates include those in which the solvent may be isotopically substituted (e.g., D₂0, acetone-d6, DMS0-d6).

A currently accepted classification system for solvates and hydrates of organic compounds is one that distinguishes between isolated site, channel, and metal-ion coordinated solvates and hydrates. See, e.g., K. R. Morris (H. G. Brittain ed.) Polymorphism in Pharmaceutical Solids (1995). Isolated site solvates and hydrates are ones in which the solvent (e.g., water) molecules are isolated from direct contact with each other by intervening molecules of the organic compound. In channel solvates, the solvent molecules lie in lattice channels where they are next to other solvent molecules. In metal-ion coordinated solvates, the solvent molecules are bonded to the metal ion.

When the solvent or water is tightly bound, the complex will have a well-defined stoichiometry independent of humidity. When, however, the solvent or water is weakly bound, as in channel solvates and in hygroscopic compounds, the water or solvent content will depend on humidity and drying conditions.v In such cases, nonstoichiometry will typically be observed.

Compounds of formula I include imine, carbinolamine and carbinolamine ether forms of the PBC. The carbinolamine or the carbinolamine ether is formed when a nucleophilic solvent (H₂0, ROH) adds across the imine bond of the PBC moiety. The balance of these equilibria between these forms depend on the conditions in which the compounds are found, as well as the nature of the moiety itself.

These compounds may be isolated in solid form, for example, by lyophilisation.

Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

SYNTHETIC STRATEGIES

The compounds of Formula 1 maybe prepared using the techniques described below. Some of the schemes and examples may omit details of common reactions, including oxidations, reductions, and so on, separation techniques (extraction, evaporation, precipitation, chromatography, filtration, trituration, crystallization, and the like), and analytical procedures, which are known to persons of ordinary skill in the art of organic chemistry. The details of such reactions and techniques can be found in a number of treatises, including Richard Larock, Comprehensive Organic Transformations, A Guide to Functional Group Preparations, 2nd Ed (2010), and the multi-volume series edited by Michael B. Smith and others, Compendium of Organic Synthetic Methods (1974 et seq.). Starting materials and reagents may be obtained from commercial sources or may be prepared using literature methods. Some of the reaction schemes may omit minor products resulting from chemical transformations (e.g., an alcohol from the hydrolysis of an ester, C0₂ from the decarboxylation of a diacid, etc.). In addition, in some instances, reaction intermediates may be used in subsequent steps without isolation or purification (i.e., in situ).

In some of the reaction schemes and examples below, certain compounds can be prepared using protecting groups, which prevent undesirable chemical reaction at otherwise reactive sites. Protecting groups may also be used to enhance solubility or otherwise modify physical properties of a compound. For a discussion of protecting group strategies, a description of materials and methods for installing and removing protecting groups, and a compilation of useful protecting groups for common functional groups, including amines, carboxylic acids, alcohols, ketones, aldehydes, and so on, see T. W. Greene and P. G. Wuts, Protecting Groups in Organic Chemistry, 4th Edition, (2006) and P. Kocienski, Protective Groups, 3rd Edition (2005).

Generally, the chemical transformations described throughout the specification may be carried out using substantially stoichiometric amounts of reactants, though certain reactions may benefit from using an excess of one or more of the reactants. Additionally, many of the reactions disclosed throughout the specification may be carried out at about room temperature (RT) and ambient pressure, but depending on reaction kinetics, yields, and so on, some reactions may be run at elevated pressures or employ higher temperatures (e.g., reflux conditions) or lower temperatures (e.g., -78°C. to o°C.). Any reference in the disclosure to a stoichiometric range, a temperature range, a pH range, etc., whether or not expressly using the word range, also includes the indicated endpoints.

Many of the chemical transformations may also employ one or more compatible solvents, which may influence the reaction rate and yield. Depending on the nature of the reactants, the one or more solvents may be polar protic solvents (including water), polar aprotic solvents, non-polar solvents, or some combination. Representative solvents include saturated aliphatic hydrocarbons (e.g., n-pentane, n-hexane, nheptane, n-octane); aromatic hydrocarbons (e.g., benzene, toluene, xylenes); halogenated hydrocarbons (e.g., methylene chloride, chloroform, carbon tetrachloride); aliphatic alcohols (e.g., methanol, ethanol, propan-i-ol, propan-2-ol, butan-i-ol, 2methyl-propan-i-ol, butan-2-ol, 2-methyl-propan-2-ol, pentan-i-ol, 3-methyl-butan-ιοί, hexan-i-ol, 2-methoxy-ethanol, 2-ethoxy-ethanol, 2-butoxy-ethanol, 2-(2-methoxyethoxy)-ethanol, 2-(2-ethoxy-ethoxy)-ethanol, 2-(2-butoxy-ethoxy)-ethanol); ethers (e.g., diethyl ether, di-isopropyl ether, dibutyl ether, 1,2-dimethoxy-ethane, 1,2diethoxy-ethane, i-methoxy-2-(2-methoxy-ethoxy)-ethane, i-ethoxy-2-(2-ethoxyethoxy)-ethane, tetrahydrofuran, 1,4-dioxane); ketones (e.g., acetone, methyl ethyl ketone); esters (methyl acetate, ethyl acetate); nitrogen-containing solvents (e.g., formamide, Ν,Ν-dimethylformamide, acetonitrile, N-methyl-pyrrolidone, pyridine, quinoline, nitrobenzene); sulfur-containing solvents (e.g., carbon disulfide, dimethyl sulfoxide, tetrahydro-thiophene-1,1,-dioxide); and phosphorus-containing solvents (e.g., hexamethylphosphoric triamide).

PREFERRED GENERAL SYNTHETIC STRATEGIES

A key step in the synthesis of the PBC compounds is the ring closure step to form the 8membered B-ring. Suitable synthetic strategies for this ring closure step are known in the art and have been reviewed with regard to the preparation of the related PBD compounds (1, 21).

Synthetic Strategies Involving Preparation of the B-Ring via a PBC Dilactam

Several of these synthetic strategies for preparing PBC compounds are based on forming a key PBC dilactam that can then undergo a reduction reaction to provide the desired PBC compound.

Route 1

The nitro group of precursor [1] may be reduced to a nucleophilic anilinic amine [2] which may then react with an electrophilic substituent from the pyrolidine ring to produce the B-ring of the PBC dilactam [3] by formation of an amide. Catalytic hydrogenation in the presence of palladium on charcoal may be used to carry out the reduction (WO 2004/043963) followed by acid catalysed cyclisation (37), with e.g. HC1, to produce the key PBC dilactam [3]. Other reagents and conditions may be used for carrying out the reduction (35-38). R1-R7 below represent the desired final substituents, or the precursors or protected forms thereof.

[1] [2] [3]

The amide group of the PBC dilactam [3] formed in the cyclisation step may be reduced directly to provide the desired PBC compound [4] using covalent hydrides, such as LiAlH₄ or NaBH₄ (21, 39). The desired PBC compound [4] is shown below as an imine but, as discussed above, the N=C may also exist in the form of a carbinolamine [NHCH(OH)], or as a carbinolamine alkyl ether. The efficiency of the regioselective reduction of the carbonyl is affected by factors such as A-ring substitution pattern, nitrogen-protecting groups, the C-ring substitution pattern and the source of the hydride. Hence, protection of the nitrogen with an appropriate nitrogen protecting group may assist the dilactam reduction. A protecting group may be added by treating the dilactam [3] with a kinetic base (e.g. NaH), followed by addition of an electrophile (e.g. CH3-O-CH2-CI [M0M-C1] as shown below) which does not affect the stereochemistry of the pyrrolidine (39).

Route 2

The PBC dilactam [3] may also be produced by a reductive cyclization of an azido group with a carboxylate ester [6]. The azide compound [6] may be prepared by reacting the corresponding nitro compound with sodium azide, NaN₃ (40). The azide reduction may be carried out using silicon-based reagents, e.g. hexamethyldisilathiane [HMDST] (40-42), ferrous sulphate (43) or ferric chloride with sodium iodide (44).

[1]

The dilactam [3] can be reduced to the desired PBC compound [4] as discussed in relation to Route 1 above.

Route 3

The dilactam [9] may be prepared using a hypovalent iodine reagent phenyliodine (III) bis(trifluoroacetate) PIFA to cyclize the B-ring (45). Saponification of the precursor [7] with LiOH and amide coupling with meth oxamine give the N-alkoxyamide [8]. Treatment of [8] with PIFA removes the hydrogen from the nitrogen to produce an Nacylnitrenium species which undergoes an intramolecular electrophilic aromatic substitution to provide the dilactam [9], where Rs is OCH₃. The Rs methoxy group can be removed from dilactam [9] by treatment with molybdenum hexacarbonyl to give the dilactam [3], where Rs is H, which may then be reduced to the desired PBD compound [4] as in Route A above.

The nucleophilic character of the phenyl ring is critical to the cyclization and electrondonating groups, such as alkoxy groups e.g. CH₃0-, at R₅ and R6 are important to provide the required nucleophilic character.

Synthetic Strategies Involving Preparation of the B-Ring by Cyclization of an Aldehyde or an Aldehyde Equivalent

These synthetic strategies form the B-ring by cyclization using an aldehyde, a protected aldehyde (e.g. acetal or thioacetal) or a hydroxyl group (which can be oxidised to the aldehyde) as an electrophilic group in the PBC precursor.

Route 4

Route 4 involves reduction of a nitro group on the A-ring of the precursor [io] to give the amine [11] which then undergoes a cyclization with the aldehyde group to form the B-ring [12]. The reductive cyclization maybe carried out using catalytic hydrogenation with palladium on charcoal (46, 47) or with Raney-nickel (48, 49), although other reductive cyclization conditions are known (50, W02007/085930). The desired PBC compound [12] commonly may be the form of the carbinolamine [Rg =H, R_g = OH], or of an imine where Rg and R_g together form a double bond.

Route 5

A useful strategy to form PBC compounds is to use a thioacetal as a protected aldehyde. Protection of the aldehyde can be carried out after A- to C- ring coupling, or alternatively a C-ring carrying a thioacetal may be coupled to the A-ring.

The amine [14] may be prepared by reduction of the nitro group of [13], subsequent removal of the thioacetal and cyclization provides the desired PBC compound [4]. Mercury (II) chloride may be used as the reagent for removing the thioacetal and effecting cyclization (51), although other reagents may also be used (52,53).

Generally, the thioacetal group -CH(SR)₂ has C1-C7 alkyl groups, such as methyl or ethyl, as the R groups and suitable thioacetal protected C-rings may be prepared via a literature method (54).

The thioacetal protecting group is robust and a wide variety of reactions may be carried out on the nitro thioacetal scaffold [13] as shown by the preparation of the related monomeric PBD conjugates, such as those involving polypyrrole moieties (55), and the related dimeric PBD species (33, 56, 57) using this strategy.

Route 6

Acetals [15] where R is a C1-C7 alkyl group, such as methyl or ethyl, may be used as a protected aldehyde and, following deprotection under mild acidic conditions, may be cyclized to form the B-ring of PBCs [4] (21).

Zinc chloride and chlorotrimethylsilane may provide a stereoselective cyclization (58,

59)·

Route 7

The PBC [4] maybe prepared by consecutive Staudinger/intramolecular aza-Wittig reactions of a precursor [16] containing azide and aldehyde functional groups. The reaction proceeds via an imminophosphorane intermediate [17] (34, 60, 61).

The precursor [16] containing azide and aldehyde functional groups may be prepared from 2-nitrobenzoic acid derivatives and prolinol derivative (34).

Route 8

Cyclization of the B-ring may be achieved using a precursor [18] containing an amine group that has a protecting group at Rs (30, 62-66, WO 00/12508, W02005/085260). The hydroxyl group in [18] is oxidised to an aldehyde [19] which maybe reacted with the protected amine to form the carbinolamine [12] where Rs = protecting group and R = OH. The protecting group Rs in the carbinolamine [18] prevents imine formation through elimination, which allows a range of further modifications to be carried out on the compound without any complications from an imine. Thus, [18] may undergo addition of side chain substituents before formation of the imine. Deprotection of the nitrogen can be carried out as the last step to give the imine [4].

[18] [19] [12]

When alloc is used as the protecting group Rs, then the deprotection to remove the nitrogen protecting group of [12] is carried out using palladium, followed by the elimination of water to give the imine.

Synthesis of C-Ring Precursors

C-Ring precursors may be prepared from proline and from proline derivatives. For example, a protected proline [20] derivative where the protecting group PG is benzyloxycarbonyl may be converted to an acid chloride by reacting with iBuOCOCl in triethylamine. Treatment of this acid chloride with diazomethane provides the corresponding diazomethyl ester intermediate, which can be treated with silver benzoate in methanol to provide the methyl ester [21]. Hydrolysis of the methyl ester with LiOH in dioxane, followed by reduction of the carboxylic acid with BH3.THF provides the alcohol [22]. If desired, this alcohol may be protected as the carbonate by reacting with CH₃OC(O)C1 followed by removal of the benzyloxycarbonyl protecting group by hydrogenation using H₂ with a Pd/C catalyst in methanol to give the amine [23] with the protected alcohol. Synthesis of the product [23] where Ri = R₂ = R₃ = H has been reported in a good overall yield (34).

[20] [21]

[22] [23]

A 2-nitrobenzoic acid or a 2-azidobenzoic acid can be converted to its acid chloride and coupled with the protected amine [23] which following deprotection of the alcohol and oxidation provides the aldehyde containing precursor [16] suitable for cyclization.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

Figure 1: Shows the structures of SJG-136 and PBC 3 Dimer;

Figure 2: Shows an overlay of SJG-136 and PBC 3 Dimer structures with identically placed imines (R6-connection);

Figure 3: Shows that the PBC 3 Dimer (blue) is comfortably accommodated in the minor groove of the sequence 5 -TATAGATCTATA-3’ (top panel) with little distortion of DNA bases (green box, bottom panel); and

Figure 4: Shows a snapshot of MD simulation showing the PBC- R6-Imidazole-MPB (Figure 4A), interacting with 5’-GGGGGGGGCC-3’ in an identical manner to the highly cytotoxic KMR-28-39 (PBD-C8-Imidazole-MPB) (Figure 4B).

EXAMPLES

Unless otherwise stated all reagents maybe obtained from Sigma-Aldrich, Fisher Scientific and Fluorochem Limited.

Solvents were purchased from Sigma-Aldrich (UK) and Fisher Scientific (UK). Anhydrous reactions were carried out in pre-oven-dried glassware under an inert atmosphere of nitrogen. Thin Layer Chromatography (TLC) was performed on silica gel aluminum plates (Merck 6o, F₂₅₄), and column chromatography was carried out using silica gel (Merck 9385, 230-400 mesh ASTM, 40-63 μΜ) whilst monitoring by thin layer chromatography: UV (254 nm) and an aqueous alkaline solution of potassium permanganate as stain. All NMR spectra were obtained at room temperature using a Bruker DPX400 spectrometer, for which chemical shifts are expressed in ppm relative to the solvent and coupling constants are expressed in Hz. All Liquid Chromatography Mass Spectroscopy (LCMS) analysis were performed on a Waters Alliance 2695 with water (A) and acetonitrile (B) comprising the mobile phases. Formic acid (0.1%) was added to the acetonitrile to ensure acidic conditions throughout the analysis. The gradient conditions were: 95% A/5% B for 2 mins, which was increased to 50% B over 3 mins. The gradient was then held at 50% B for 1 mins, and then increased to 95% B over 1.5 mins. The quantity of B was then returned to 5% over 1.5 mins, and held constant for 0.5 mins, (the total duration of each run being 10 mins.) The flow rate was 0.5 mL/mins., 200 pL was split via a zero dead volume T piece which passed into the mass spectrometer. The wavelength range of the UV detector was 220-400 nm. Function type: Diode array (535 scans). Column type: Monolithic C18 50 X 4.60 mm. Mass spectrometry data were collected using a Waters Micromass ZQ instrument coupled to a Waters 2695 HPLC with a Waters 2996 PDA. Waters Micromass ZQ parameters used were: Capillary (kV), 3.38; Cone (V), 35; Extractor (V), 3.0; Source temperature (°C), 100; Desolvation Temperature (°C), 200; Cone flow rate (L/h), 50;

De-solvation flow rate (L/h), 250. Microwave reactions were carried out on an Anton Paar Monowave 300 microwave synthesis reactor. Yields refer to isolated material (homogeneous by TLC or NMR) unless otherwise stated and names are assigned according to IUPAC nomenclature.

General Methods: Molecular Dynamics (MD) Simulations

Molecular dynamics simulations consist of the calculation of the time-dep endent behaviour of molecular systems, and have provided valuable information on the changes in conformations of biomolecules (for example proteins or nucleic acids) as predicted over a certain time-course.

Classical MD simulations can be performed in explicit or implicit solvent, with explicit containing solvent molecules (and thus dramatically increasing the necessary computational power), and implicit solvent containing a representation of solvent in the form of a continuous medium.

In explicit solvent simulations, all atoms contained in the system (z.e. all nucleic acid, ligand and water atoms in a DNA sequence) are moved in short time-steps (e.g. 2fs), each step is saved and the forces acting on the atoms are calculated and an atom’s position and velocity are updated using Newton’s Laws. This process is repeated billions of times for every atom in the system, resulting in the production of a dynamic simulation trajectory, illustrating an atom’s movements within a system. An identical process is undertaken for implicit solvent simulations, except without solvent molecules and as such the complex, on its own, is simulated.

Molecular dynamics simulations were conducted using AMBER (vii) (74) software. Each DNA sequence was constructed using nab, antechamber was used to convert the structures to mol2 files with the application of Gasteiger charges, and missing parameters were generated for each ligand using parmchk. The gaff and DNA optimized parm99bsco (75) force-fields were loaded for DNA and xleap was used to manually position each ligand into each sequence individually by creating the covalent bond between the exocyclic NH₂ of the reacting guanine and each ligand using parameters previously derived through molecular mechanics calculations. . Parm99bsco was used as it is a refined version of parm99, where α/γ rotation of nucleic acids is considered (75). Na⁺ ions were placed along the DNA backbone using xleap to neutralize the DNA and adducts were solvated using a truncated octahedron TIP3P water box of maximum dimension 10 A. Each adduct was minimized in a gradient manner by initially placing the DNA under a high force constraint to enable the ligand to find its local energy minimum, followed by a reduction in force in a periodic manner and a relaxation of restraints. Once the full system was minimized, it was heated slowly to 300 K over 20 ps using the SHAKE algorithm to restrict vibrations of C-H bonds (76), followed by an unrestrained equilibration step of too ps to relax the density of water. Once in equilibrium, production simulations were run for a period of 10 ns and atomic coordinates were saved at ι-ps intervals. Production simulations of 10 ns were conducted using an identical protocol, with structures docked in the minor groove of each sequence in a non-covalent manner.

Simulations of io ns duration were undertaken and free energy calculated using the MM-PBSA method in AMBER 11, a method shown to be most accurate in free energy estimation in explicit solvent simulations (77).

Binding free energy can be calculated as follows:

AG^C bind — AG bind vacuum + AG complex “ (AG°ligand + AG^Q receptor) where AG%md is determined by solving the linearized Poisson-Boltzmann equation (78)

AG complex — Emm + G polar solvation energy + Gnonpolar solvation energy TS

Solvation energies (both polar and non-polar) are considered, Emm corresponds to internal, electrostatic and vdW interactions and S is solute entropy.

The final binding energy is represented as:

AG°bind — AEmM + AG°solv - T AS

Entropy contribution can be calculated using normal mode analysis. However, this is impractical as normal mode analysis calculations introduce significant error into final values and are computationally expensive. As states of similar entropy are being assessed and therefore comparable, these calculations were not undertaken.

G = Emm + Gpbsa -TSmm

Emm ⁼ Ebond + Eangle + Etors + Evdw + Eelec where:

G = calculated average free energy (kcal/mol),

Gpbsa = solvation free energy (Poisson Boltzmann equation with estimate of non-polar free energy)

TSmm = solute entropy

Emm = average molecular mechanical energy (consisting of energies for bond, angle, torsion, van der Waals and electrostatics

One hundred snapshots of the MD simulations were taken at equal intervals over the 10 ns duration, and molecular mechanics (MM) calculations were performed using pbsa (74)·

Non-covalent Simulations

PBDs locate the minor groove of DNA through a combination of hydrophobic and noncovalent interactions, before forming an essential hydrogen bond between Nio of the molecule and the exocyclic C2-amino of guanine. Once this hydrogen bond is formed, the PBD is pulled into the minor groove and undergoes nucleophilic attack to form the covalent attachment. As such, it is necessary to perform non-covalently bound simulations to assess the DNA-interactive potential of DNA-targeting molecules such as PBDs. Free energy of binding calculations performed on these simulations help in the assessment of DNA-binding potential.

Free energy of binding (kcal/mol) calculations are used to ascertain the degree of affinity of a ligand for its receptor. Hydrogen bonding analysis and the examination of non-bonded interactions also support the evaluation of binding of ligands to sequences of DNA. As ligands recognize the minor groove through these interactions, quantitative and qualitative analysis of each provides a valuable insight into the strength of DNA: ligand interaction.

Example 1

A definite hierarchy can be observed, with PBC3 [a compound of formula (VI)] showing free energy of binding values greater than -2okcal/mol, close in value to a PBD equivalent DC-81. Furthermore, in non-covalent simulations PBC3 maintains a hydrogen bond between the B-ring nitrogen and C2-amino of guanine, a vital prerequisite to nucleophilic attack.

Structure	Free Energy of Binding (kcal/mol) (+/- 10% Standard Deviation) in 5’-TATAAGATATA-3’ (binding site underlined)
DC-81 N=\y^H	-23-12
PBC1 MeO	-I2.94
PBC 2 MeO	-I9.23
PBC 3	-21.12

MeCT'	τ o
PBC 4			-17-05
0	N=	\.^H
		γΛ
Ι\Λ Ά		N^/
MeO		<
		\x 0

Table 1: Free energy of binding (kcal/mol) of each PBC monomeric structure with the sequence s’-TATAAGATATA-.^’

Less favourable free energy of binding values were observed for PBC 1 [a compound of formula (IV)] and PBC 2 [a compound of formula (V)] than wereobserved for PBC 3. This was due to modifications being on the DNA-interacting face of the molecule for PBC 1 and PBC 2 thereby interfering with the formation of a hydrogen bond between the B-ring nitrogen of the imine and guanine. PBC 4 [a compound of formula (VII)] also exhibited a poorer free energy of binding than PBC 3. This was due to a lack of interaction with the C2-amino of guanine for PBC 4, with the PBC 4 structure not remaining over the intended binding triplet (5’-AGA-3’).

Example 2

The C8-linked PBD dimer structure SJG-136 (Figure 1) is currently in Phase II clinical trials, selectively interacting with the DNA sequence 5’-Pu-GATC-Py-3’.

Alignment of the R6-linked PBC molecule in dimer form PBC 3 Dimer (Figure 1) with SJG-136 suggests an identical span of the molecules and identically placed imines (Figure 2). Therefore, comparable cytotoxicities should be expected. Furthermore, MD simulations have shown that when covalently bound in the DNA minor groove to a sequence idealised for interaction with the PBD dimer SJG-136 Cs’-TATAGATCTATA3’), the PBC 3 Dimer is comfortably accommodated in the minor groove, causing negligible distortion of the DNA helix, both of which are pre-requisites for the cytotoxic activity of DNA-interactive agents (Figure 3). These observations are supported by free energy of binding calculations which illustrate PBC-3 dimer as having a highly similar free energy of binding value compared to SJG-136.

Structure	Free Energy of Binding (kcal/mol) in V-TATAGATCTATA-1’ iSD +/10%) (binding site underlined)
SJG-136	-45-73

YP 0	^xOMe MeO^	X2 0
PBC 3 Dimer					-45-93
H _N			_Λ N=x	H
Λϊ ΥΠτ
VN K A				nJ
	OMe	MeO
\\ 0			0

Table 2: Free energy of binding (kcal/mol) of SJG-136 and PBC3 Dimer structure with the sequence s’-TATAGATCTATA-^’

Example 3

An example of the equivalence of the PBC family to the PBDs is the design of a molecule using a GC-selective MPB unit. The highly cytotoxic PBD conjugate KMR-28-39 is active in the femtomolar range in some cancer cell lines, a characteristic attributed to its strong affinity for GC-rich DNA sequences. KMR-28-39 is comprised of a PBD coupled to an imidazole-MPB unit through its C8-position, with the imidazole-MPB providing the structure with its enhanced GC-selectivity through unique molecular interactions with DNA bases (see Table 3).

Structure	Free Energy of Binding (kcal/mol) in s’-GGGGGTCGCC3’ (binding site underlined)
PBC-R₍₎-Im-MPB 0 \ /^Ν~~ϊΐ ^{0 r} ° XVoJ⁵o'	-61.42
PBD-C8-Im-MPB (KMR-28-39) N=\ H ^N H MeO H 'O'' Ij ⁰ N-J /	-59-83

Table 3: Free energy of binding (kcal/mol) of PBC-Imidazole-MPB, and PBD15 Imidazole-MPD (KMR-28-39) over a 10 ns explicit solvent while docked in the sequence 5-GGGGGGGGCC-3’

When the Imidazole-MPB moiety is tethered to the equivalent R6 position of the PBC molecule, the new PBC-Imidazole-MPB structure produces the same interactions with DNA as KMR-28-39 (PBD-C8-Imidazole-MPB). This is exemplified in snapshots of MD simulations of KMR-28-39 (PBD-C8-Imidazole-MPB) (Figure 4B) and PBC-R65 Imidazole-MPB (Figure 4A) which illustrate identical hydrogen bonding interactions formed between each structure and a poly-G DNA sequence.

When modelled against the sequence s’-GGGGGGGGCC-3’ and covalently bound to G3 (underlined), hydrogen bonding interactions are formed between the imidazole 10 nitrogen and G5, and between the terminal carbonyl and G7 in the case of both structures: PBC-R6-Imidazole-MPB and PBD-C8-Imidazole-MPB (Figure 4 and 5). As such, PBC structures are expected to produce similarly high cytotoxicity to C8-linked PBD structures.

Furthermore, free energy of binding calculations (Table 3) show the potential of the new PBC conjugates to interact with DNA in a similar manner to KMR-28-39, with near-identical free energy of binding values observed for PBC and PBD conjugates.

Example 4

A suitable PBC scaffold 10 is prepared by reacting the A-ring precursor 1 with the Cring precursor 2 in the following reaction scheme.

O

-OH = CuBr2

DMSO r.t.

KNO₃

TFA *

0°C

H2 (45 psi,

Parr) (MeO)₃CH_xO_x-<x-NO2HO_K Pd/C _XO TsOH || T .- (10%w/w)

MeOH * EtOH/ * ^XO _r t -0 0 Lv EtOAc ^z r.t.

Alloc

TEMPO BAIB _rCH₂CI₂r.t.

PPh₃

CH₂CI₂*

r.t.

Pd(PPh₃)₄pyrr,

HCI (aq)_ Tt

Commercially available 3',4'-Dimethoxyacetophenone 1 (Sigma-Aldrich) will be reacted with S-(+)-2-pyrrolidinemethanol 2 (Sigma-Aldrich) in a copper(II) carbonyl85 amine coupling reaction to provide the product 3 (79). The aromatic ring of 3 will then undergo aromatic nitration to produce the nitro compound 4. The carbonyl group of compound 4 will then be protected as the ketal 5 by reacting with trimethyl orthoformate (72, 73). Palladium-carbon catalysed reduction of the nitro group of ketal 5 will then produce the aniline derivative 6 (27). The amine group of 6 will then be protected with an alloc protecting group (72, 73) to give compound 7. The B-ring of compound 8 will be formed by an oxidative cyclisation using TEMPO and BAIB as oxidising agents (75, 76). Removal of the oxygen protecting groups will give the imine 9 (7, 72, 73, 77). Treatment with acid will remove the ketal to provide the PBC scaffold compound 10.

Example s

A reaction scheme for preparing a PBC dimer 20 is shown below:

OH

DMSO, r.t.

HO

Commercially available acetovanillone (4’-hydroxy-3'-methoxyacetophenone) n (Sigma-Aldrich) will be reacted with S-(+)-2-pyrrolidinemethanol 2 (Sigma-Aldrich) in a copper(II) carbonyl-amine coupling reaction to provide the product 12 (79). The aromatic ring of 12 will then undergo aromatic nitration to produce the nitro compound 13. The carbonyl group of compound 13 will then be protected as the ketal

14. Reaction of ketal 14 with 1,3-diiodoproane in the presence of aqueous potassium carbonate and DMF will give the dimeric nitro compound 15. The nitro groups of 15 will be reduced to amine groups to give the aniline derivative 16 via palladium catalyzed reduction (27). The aniline derivative 16 will be treated with allyl chloroformate in the presence of pyridine to give the Alloc protected compound 17 (72, 73). The ring cyclisation is carried out using a TEMPO/BAIB system (75, 76) to afford the protected cyclised dimer 18. Treatment of the Alloc protected PBC precursors 32 with Pd(PPh3)4 in the presence of pyrrolidine removes the Alloc protecting group to produce dimer compound 19 (7, 72, 73, 77). Finally, treatment with acid will remove the ketal protecting groups to provide the PBC dimer 20.

Example 6

A range of side chain groups suitable for attaching to PBC compounds may be prepared (79, 80). A side chain group methyl 4-(4-aminophenyl)-i-methyl-if/-pyrrole-2carboxylate 34 was prepared as described below.

Br

A mixture of methyl 4-bromo-i-methyl-iH-pyrrole-2-carboxylate (750 mg, 3.44 mmol),

4-(4,4,5,5-tetramethyl-i,3,2-dioxaborolan-2-yl)aniline (905 mg, 4.13 mmol) and potassium carbonate (1.43 g, 10.3 mmol) in toluene/ethanol/water (9:3:1) (13 mL total) was degassed with nitrogen for 5 mins. Tetrakis(triphenylphosphine)palladium(o) (230 mg, 6 mol%) was then charged and the reaction mixture was irradiated with microwaves at 100 °C for 15 mins. Water (10 mL) was then added to the reaction mixture, which was extracted with ethyl acetate (3 x 40 mL). The combined organic extracts were then dried over sodium sulfate, filtered and concentrated. The resulting residue was purified by column chromatography (silica), eluting with ethyl acetate/hexanes (from 0% to 50%), to give the title compound (145 mg, 18%) as a yellow solid.

MS (ES+): m/z = 231 (M+H)⁺; LCMS: t_R = 5.17 min.

Example 7

A monomeric conjugate compound 36 will be prepared using the following reaction scheme:

H₂, (45 psi,

Parr) Pd/C (10%w/w)

EtOH/ EtOAc r.t.

Alloc

OH

AllocCI

Pyr

CH₂CI₂r.t.

DHP pTSA

EtOAc r.t.

The first step in preparing the monomeric conjugate compound 36 is by treating acetovanillone (4’-hydroxy-3'-methoxyacetophenone) 11 (Sigma-Aldrich) with methyl 4-bromobutanoate 2 (Fluorochem) in DMF in the presence of potassium carbonate as a 15 base (7, 77) to give the coupled product 22 (77). Product 22 will be reacted with S-(+)2-pyrrolidinemethanol 2 in a copper(II) carbonyl-amine coupling reaction to provide the product 23. The aromatic ring of 23 will then undergo aromatic nitration to produce the nitro compound 24. The carbonyl group of compound 24 will then be protected as the ketal 25 (72, 73). The nitro group of compound 25 will then be reduced (27) to the corresponding amine 26 using H₂ and Pd/C (10% w/w). The aniline derivative 26 will then be treated with allyl chloroformate in the presence of pyridine to give the Alloc protected compound 27 (72, 73). The ring cyclisation will be carried out using oxidation conditions of a TEMPO/BAIB system (75, 76) to afford the cyclised compound 28. The alcohol group of compound 28 will be protected by treating it with DHP in presence of PTSA to afford 29 (72, 73). The terminal ester of 29 will be hydrolysed to corresponding carboxylic acid 30 using sodium hydroxide in dioxane to facilitate addition of heterocyclic fragments by peptide coupling (78). The carboxylic acid 30 will be coupled (77, 78) with a suitable heterocyclic amine, ethyl 4amino-i-methyl-iH-2-carboxylate 31 (22-26, 77, 78), to give the protected compound

33. A further peptide coupling of compound 33 will be carried out with methyl 4-(4aminophenyl)-i-methyl-iH-pyrrole-2-carboxylate 34 which was prepared as described in Example 6. These peptide coupling reactions will be carried out using EDCI, DMAP and DMF to give a protected PBC conjugate 35. Treatment of the Alloc protected PBC conjugate 35 with Pd(PPh3)4 in the presence of pyrrolidine will remove the Alloc protecting group (7, 72, 73, 77). Finally, treatment with acid will remove the ketal protecting groups to provide the PBC conjugate 36.

Example 8: HPLC Assay

Ligand-DNA Complex Preparation: Ligand-DNA complexes will be prepared by incubating the ligands with hairpin oligonucleotides of chosen sequence in a 4:1 molar ratio at room temperature. Samples will be withdrawn at various time intervals and subjected to Ion-Pair RPLC and mass spectrometry analysis as described below.

Ion-Pair Reversed-Phase Liquid Chromatography: Chromatography will be performed on a Thermo Electron HPLC system equipped with a 4.6 x 50 mm Xterra MS C18 column packed with 2.5 μΜ particles (Waters Ltd, UK), an UV1000 detector, an AS3000 autosampler, a SCM1000 vacuum degasser and Chromquest software (Version 4.1). A gradient system of 100 mM tri ethyl ammonium bicarbonate (TEAB) as buffer A, and 40% acetonitrile in water (HPLC grade, Fischer Scientific UK) as buffer B will be used. For buffer A, a 1M pre-formulated buffer of TEAB (Sigma-Aldrich, U.K) will be diluted to 100 mM with HPLC grade water (Fischer Scientific, U.K). The gradient will be ramped from 90% A at 0 mins to 50% A at 20 mins, 65% A at 30 mins and finally to 10% A at 45 mins. UV absorbance will be monitored at 254 nm, and fractions containing separated components will be collected manually, combined when appropriate, lyophilized and analyzed using MALDITOF mass spectrometry as described below.

Mass Spectrometry Analysis (ESI-MS): ESI-MS spectra will be acquired on a Micromass Q-TOF Global Tandem Mass Spectrometer (Waters, UK) fitted with a NanoSpray ion source. Negative mode will be used for data acquisition, and the instrument will be calibrated with ions produced from a standard solution of taurocholic acid (io pmole/μΐ) in acetonitrile. The HPLC fractions will be collected and lyophilized (Speedvac, Thermo Electron, UK) and mixed with a 1:1 v/v mixture of 40% acetonitrile/water and 2omM triethylamine/water (TEA, Fischer Scientific, UK) which will also be used as electrospray solvent. 3-5 pL of sample will be loaded into a metalcoated borosilicate electrospray needle with an internal diameter of 0.7 mm and a spray orifice of 1-10 pm (NanoES spray capillaries, Proxeon Biosystems, UK) which will be positioned at ~io mm from the sample cone to provide a flow rate of ~20 nl/min. Nitrogen will be used as the API gas, and the capillary, cone and RF Lens 1 voltages will be set to values such as 1.8-2.0 kV, ~ 35 V and 50 V, respectively, to ensure minimum fragmentation of the ligand/DNA adducts. The collision and MCP voltages will be set to values such as 5V and 2200 V, respectively. Spectra will be acquired over the m/z range 1000-3000.

Mass Spectrometry Analysis (MALDI TOF): Samples will be diluted with matrix (37 mg THAP in 1 mL ACN, 45 mg ammonium citrate in 1 mL water - mixed 1:1 for matrix) either 2:1,1:1 or 1:5 (sample:matrix) to determine the most effective ratio. 1 pl of sample/matrix mixture will be spotted onto the MALDI target plate and allowed to dry. Analyses will be carried out on a Voyager DE-Pro with a nitrogen laser in positive linear mode using delayed extraction (500 nsec) and an accelerating voltage of 25,000 V. Acquisition will be between 4000 - 15000 Da with 100 shots/spectrum.

Example 9: Fluorescent Resonance Energy Transfer (FRET) DNA Thermal Denaturation Assay

400 nM solutions of fluorescence-tagged oligonucleotide (e.g., 5'-Fam-TATA-(X)_nTATA-Tamra-3'; where X = any number or combination of bases) in FRET buffer (50 mM potassium cacodylate, pH 7.4) will be prepared by diluting a 20 pM stock solution in water. This solution will be heated at 85°C for 5 mins before cooling to room temperature over 5 hours to promote annealing. The ligand solution will be prepared initially in a concentration double that required for the final solution, and dilution from the initial 10 mM DMSO stock solution will be carried out using FRET buffer. 50 pL of the annealed DNA and 50 pL of ligand solution will be placed in a well of a 96-well plate (MJ Research Inc, USA) which will be processed in a DNA Engine Opticon (MJ Research). Fluorescence readings will be taken at intervals of o.5°C over the range 305 ioo°C, with a constant temperature maintained for 30 seconds prior to each reading.

The incident radiation will be 450-495 nm with detection at 515-545 nm. The raw data will be imported into the Origin program (Version 7.0, OriginLab Corp. USA), and the graphs smoothed using a 10-point running average prior to normalization. Determination of melting temperatures will be based on obtaining values at the 10 maxima of the first derivative of the smoothed melting curves using a script. The difference between the melting temperature of the sample and that of the blank (z.e., the ATm) will be used for comparative purposes.

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Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A compound of formula (I):

(I) and salts or solvates thereof, wherein:

R3 is selected from H, R, =0, =CH-R, =CH2, R14, (CH2)j-S02R, 0-S02R, COR, CN;

R4, R5 and R7 are independently selected from H, R, SH, SR, Ri4, N02, Me3Sn and halo; each R and R’ is independently selected from optionally substituted Ci-i2 alkyl, C2-i2 alkenyl, C3.2O heterocyclyl, C4.2O heterocyclalkyl, C5.2O heterocyclalkenyl, C3.2O heteroaryl, C4-32 heteroaralkyl, C5.32 heteroaralkenyl, C5.2O aryl groups C6-32 aralkyl and C7.32 aralkenyl;

each R” and R’” is independently selected from H, and optionally substituted Ci-i2 alkyl; each Ri4 is independently selected from (CH2)jOH, (CH2)jOR, (CH2)jNH2, (CH2)jNHR, (CH2)jNRR’, (CH2)j C02R, (CH2)jC02H, 0-(CH2)k-NR”R”’, C(=0)-NH-(CH2)k-NR”R”’, C(=O)-NH-C6H4-(CH2)j-R” and C(=0)-NH-(CH2)k-C(=NH)NR”R”’;

m is o or 1;

n is 0 or 1;

each j is an integer independently selected from 0 to 6;

each k is an integer independently selected from 1 to 6;

m + n = 0 or 1; and when m + n = 1 then A is C=0 and W is absent; and when m + n = 0 then one of A or W is C=0 and the other is CH2;

and either:

(i) Rs and Rg together form a double bond;

(ii) Rs is H and Rg is OH;

(iii) Rs is H and Rg is 0RA and RA is C1-6 alkyl; or (iv) Rs is selected from SO3H, nitrogen protecting groups, C1-6 alkyl and Ri4; and Rg is H;

wherein:

(a) the compound is a dimer with each monomer being the same or different and being of formula (I) where one of Ri, R2 and R6 of the first monomer and one of R’i, R’2 and R’6 of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers;

and the remaining of Ri and R2 of the first monomer and the remaining of R’i and R’2 of the second monomer that do not form the bridge are independently selected from H, R, =0, =CH-R, =CH2, R14, (CH2)j-S02R, 0-S02R, COR, CN, (Cxi2 alkylene)-C(O)NR”R”’, (C2.i2 alkenylene)-C(O)NR’R” and halo;

and the remaining of R6 of the first monomer and R^ of the second monomer that do not form the bridge are independently selected from H, R, R14, (CH2)jS02R, 0-S02R, COR, CN, (Ci-12 alkylene)-C(O)NR”R’”, (C2.12 alkenylene)C(O)NR’R” and halo;

or (b) one of Ri and R2 has the formula:

-X-L-X’-D;

and the remaining one of Ri and R2 is selected from H, R, =0, =CH-R, =CH2, R14, (CH2)j-S02R, 0-S02R, COR, CN, (Ci-12 alkylene)-C(O)NR”R’”, (C2_12 alkenylene)-C(O)NR’R” and halo;

and R6 selected from H, R, Ri4, (CH2)j-S02R, 0-S02R, COR, CN, (Ci-i2 alkylene)C(O)NR”R’”, (C2_12 alkenylene)-C(O)NR’R” and halo;

or (c) R6 has the formula:

-X-L-X’-D;

or is:

-(CH2)g-O-R13;

wherein Ri3 is selected from H and R;

g is o or 1;

and Ri and R2 are independently selected from H, R, =0, =CH-R, =CH2, Ri4, (CH2)j-S02R, 0-S02R, COR, CN, (Ci-12 alkylene)-C(O)NR”R’”, (C2_12 alkenylene)C(O)NR’R” and halo;

and wherein:

L is selected from an amino acid, a peptide chain having from 2 to 6 amino acids, an alkylene chain containing from 1 to 12 carbon atoms which may contain one or more carbon-carbon double or triple bonds, a paraformaldehyde chain -(0CH2)i_i2-, a polyethylene glycol chain -(OCHsCHsh-e-, which chains maybe interrupted by one or more hetero-atoms and/or optionally substituted C3.2O heteroaryl and/or C5.2O aryl groups;

D has the formula (II) or (III): or p is o or 1;

qis 1, 2, 3, 4, 5 or 6;

r is o or 1;

t is o or 1

Y3 is N or CH;

Y4 is N or CH; wherein at least one of Y3 and Y4 is CH;

R10 is H, Z-R”, Z-C02R”, Z-C(=O)-NH-(CH2)1-6-NR”R’”, and Z-C(=O)-NH-(CH2)1-6C(=NH)NR”R”’;

Z is absent or is selected from optionally substituted C3.2O heteroaryl, Ci-6 alkyl substituted C3.2O heteroaryl, -(CH2)S-C3.2O heterocyclyl, and -O-(CH2)S-C3.2o heterocyclyl group; s is o, 1, 2,3 or 4;

R11 is an optionally substituted C3-2O heteroaryl;

Ri2 is an optionally substituted C3_2O heteroaryl; and

R15, R16, Ri7, R18, Rig and R20, are independently selected from H, C1-6 alkyl and Ri4.

2. A compound of formula (I) according to claim 1, wherein m is ο, n is o, A is C=0 and W is CH2 and wherein the compound is represented by formula (VI):

(VI).

3. A compound of formula (I) according to claim 1 or 2, wherein R4 is H.

4. A compound of formula (I) according to any of the previous claims, wherein R5 is selected from H, R, OH, OR and halo.

5. A compound of formula (I) according to any of the previous claims, wherein R7 is H.

6. A compound of formula (I) according to any of the previous claims, wherein X is selected from 0, =CR”-, C(=O)NR” andNR”C(=O).

7. A compound of formula (I) according to any of the previous claims, wherein X’ is selected from 0, =CR”-, C(=0)NR” and NR”C(=0).

8. A compound of formula (I) according to any of the previous claims, wherein L is an alkylene chain containing from 3 to 12 carbon atoms which may contain one or more carbon-carbon double or triple bonds

9. A compound of formula (I) according to any of the previous claims, wherein R2 is selected from H, CH2-C02R, CH2-C02H, CH20H, CH20R.

10. A compound of formula (I) according to any of the previous claims, wherein D has the formula (II) or (III) and Rn is selected from N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene, thiazolylene, indolylene, N methylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, Nmethylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

11. A compound of formula (I) according to any of the previous claims, wherein D has the formula (II) or (III) and Ri2 is selected from N-methylpyrrolylene, furanylene, thiophenylene, N-methylimidazolylene, oxazolylene, thiazolylene, indolylene, Nmethylindolylene, benzofuranylene, benzothiophenylene, benzimidazolylene, Nmethylbenzoimidazolylene, benzooxazolylene and benzothiazolylene.

12. A compound of formula (I) according to any of the previous claims, wherein D has the formula (II) or (III), Z is absent and Ri0 is C02R”.

13. A compound of formula (I) according to claim 1, wherein the compound has the following structure:

and salts or solvates thereof, wherein:

R5 is selected from H, Ci-i2 alkyl, C2.i2 alkenyl, (CH2)jOH, 0-Ci-i2 alkyl, (CH2)jNH2, (CH2)jNH(C1-12 alkyl), =0, alkyl, =CH2, (CH2)jC02H, (CH2)jC(0)-0-C1-12 alkyl;

each j is an integer independently selected from 0 to 6;

one of A or W is C=0 and the other is CH2;

and either (i) Rs and Rg together form a double bond; (ii) Rs is H and Rg is OH; or (iii) Rs is H and Rg is 0RA and RA is Ci 6 alkyl; and wherein

100 and the remaining of Ri and R2 of the first monomer and the remaining of R’i and R’2 of the second monomer that do not form the bridge are independently selected from H, Cx-12 alkyl, C2_i2 alkenyl, (CH2)jOH, 0-Ci-i2 alkyl, (CH2)jNH2, (CH2)jNH(C1-12 alkyl), =0, =CH-Ci_x2 alkyl, =CH2, (CH2)jC02H and (CH2)jC(0)O-Ci-12 alkyl;

and the remaining of R6 of the first monomer and R’6 of the second monomer that do not form the bridge are independently selected from H, Cx-12 alkyl, C2-12 alkenyl, (CH2)jOH, 0-Cx-12 alkyl, (CH2)jNH2, (CH2)jNH(Cx-x2 alkyl), (CH2)jC02H and (CH2)jC(0)-0-Cx-12 alkyl;

or (b) one of Ri and R2 has the formula:

-X-L-X’-D;

and the remaining one of Rx and R2 is selected H, Cx-12 alkyl, C2.12 alkenyl, (CH2)jOH, O-Cx-12 alkyl, (CH2)jNH2, (CH2)jNH(Cx-x2 alkyl), =0, =CH-Cx-i2 alkyl, =CH2, (CH2)jC02H and (CH2)jC(0)-0-Ci-i2 alkyl;

and R6 selected from H, Cx-12 alkyl, C2.12 alkenyl, (CH2)jOH, 0-Cx-12 alkyl, (CH2)jNH2, (CH2)jNH(C1-12 alkyl), (CH2)jC02H and (0Η2);0(Ο)-Ο-0χ-12 alkyl;

or (c) R6 has the formula:

-X-L-X’-D;

or is:

-(CH2)g-O-R13;

wherein Ri3 is selected from H and Cx-12 alkyl;

g is 0 or 1;

and Rx and R2 are independently selected from H, Cx-12 alkyl, C2.12 alkenyl, (CH2)jOH, O-Cx-12 alkyl, (CH2)jNH2, (CH2)jNH(Cx-x2 alkyl), =0, =CH-Cx-i2 alkyl, =CH2, (CH2)jC02H and (CH2)jC(0)-0-Cx-x2 alkyl;

and wherein:

X is selected from 0, =CH-, C(=O)NH and NHC(=O) or is absent;

101

L is selected from a peptide chain having from 2 to 5 amino acids; an alkylene chain containing from 1 to 11 carbon atoms which may contain one or more carbon-carbon double or triple bonds; -(0CH2)i-i2- and -(OCHsCHsX-s-;

X’ is selected 0, =CH-, C(=O)NH and NHC(=O) or is absent;

D is selected from formula (Di):

formula (D2):

formula (D3):

(d4);

p is 0 or 1;

qis 1, 2, 3, 4, 5 or 6; r is 0 or 1;

t is 0 or 1

Y, Yi and Y2 are selected from CH, CH and N-CH3; CH, N-CH3 and CH; N, CH and NCH3; N, N-CH3 and CH; CH, S and CH; CH, CH and S; N, S and CH; N, CH and S; N, 0

102 and CH; N, CH and 0; CH, CH and O; CH 0 and CH; COH, N-CH3 and CH; and COH, CH andN-CH3;

Y3 is N or CH;

Y4 is N or CH; wherein at least one of Y3 and Y4 is CH;

Y5, Υβ and Y7 are selected from CH, CH and N-CH3; CH, N-CH3 and CH; N, CH and NCH3; N, N-CH3 and CH; CH, S and CH; CH, CH and S; N, S and CH; N, CH and S; N, 0 and CH; N, CH and O; CH, CH and O; CH 0 and CH; COH, N-CH3 and CH; and COH, CH andN-CH3;

Ye is selected from 0, S, NH and N-CH3;

Ygis selected from CH and N;

Yio is selected from 0, S, NH and N-CH3;

Yu is selected from CH and N;

R10 is H, Z-R”, Z-C02R”, Z-C(=O)-NH-(CH2)1.6-NR”R’”, and Z-C(=O)-NH-(CH2)1.6C(=NH)NR”R”’;

Z is absent or is selected from optionally substituted benzofuranylene, benzothiophenylene, indolylene, N-methyl indolylene, N-methylbenzimidazolylene, benzoxazolylene and benzothiazolylene; and

R” and R’” are independently selected from H, and Ci-i2 alkyl.

14. A compound of formula (I) according to claim 1, wherein the compound has the following structure:

or is a dimer with the following structure:

and salts or solvates thereof, wherein:

Ri, R2, R’i and R’2 are independently selected from H, Ci-i2 alkyl, C2.i2 alkenyl, (CH2)jOH, 0-Cx-12 alkyl, (CH2)jNH2, (CH2)jNH(C1-12 alkyl), =0, =CH-C1-12 alkyl, =CH2, (CH2)jC02H, (CH2)jC(0)-0-C1-12 alkyl;

each j is an integer independently selected from 0 to 6;

R5 and R’5 are independently selected from H, Ci-i2 alkyl, O-C1-6 alkyl and 0CH2Ph; R6 has the formula:

103

-X-L-X’-D;

or is:

-(CH2)g-O-R13;

wherein R13 is selected from H and Ci-i2 alkyl;

g is o or 1;

and either:

(i) Rs and Rg together form a double bond, and R’s and R’g together form a double bond;

(ii) Rs is H and Rg is OH, and R’s is H and R’g is OH; or (iii) Rs is H and Rg is O-Ci-6 alkyl, and R’s is H and R’g is O-Ci-6 alkyl; and and wherein:

X is selected from 0, =CH-, C(=O)NH and NHC(=O) or is absent;

L is selected from a peptide chain having from 2 to 5 amino acids; an alkylene chain containing from 1 to 11 carbon atoms which may contain one or more carbon-carbon double or triple bonds; -(0CH2)i-i2- and -(OCH2CH2)i_5-;

X’ is selected 0, =CH-, C(=O)NH and NHC(=O) or is absent;

D is:

or wherein:

qis 1, 2, 3, 4, 5 or 6; r is 0 or 1;

104 t is o or 1

Y, Yx and Y2 are selected from CH, CH and N-CH3; CH, N-CH3 and CH; N, CH and N-CH3; N, N-CH3 and CH;

Y3 is N or CH;

Y4 is N or CH; wherein at least one of Y3 and Y4 is CH;

Y5, Y6 and Y7 are selected from CH, CH and N-CH3; CH, N-CH3 and CH; N, CH and N-CH3; N, N-CH3 and CH;

Rio is Η, Z-H, Z-Ci-6 alkyl, Z-C02H and Z-CO2Ci_6 alkyl; and

Z is absent or is selected from optionally substituted benzofuranylene, benzothiophenylene, indolylene, N-methyl indolylene, Nmethylbenzimidazolylene, benzoxazolylene and benzothiazolylene.

15. A compound of formula (I) according to claim 1, wherein the compound is:

wherein q is selected from 1, 2, 3, 4, 5 and 6; L is an alkylene chain containing from 1 to 12 carbon atoms; Y, Yx and Y2 are CH, N-CH3 and CH or are N, N-CH3 and CH; Yi2 is selected from 0, S, NH and N-CH3; Yi3 is selected from CH and N; and R” is selected from H and C1-6 alkyl.

16. A compound of formula (I) according to any of claims 1 to 14, wherein the compound is a dimer with each monomer being the same and being of formula (I).

17. A compound of formula (I) according to any of claims 1 to 14, wherein the compound is a dimer where Rc of the first monomer and R’c of the second monomer form together a bridge having the formula -X-L-X’- linking the monomers.

18. A compound of formula (I) according to any of claims 1 to 14, wherein the compound is a dimer of formula (A12):

105 och3 ch3o °^(CH2)^° (A12).

19. A compound of any one of claims 1 to 18 for use in the treatment of a

5 proliferative disease.

20. A pharmaceutical composition comprising a compound of any one of claims 1 to 18 and a pharmaceutically acceptable carrier or diluent.

10

21. The use of a compound according to any one of claims 1 to 18 in the manufacture of a medicament for the treating a proliferative disease.

106

107