# Patent

## Title
Phthalazinone derivatives

## Abstract

Compounds of the formula (I):




wherein A and B together represent an optionally substituted, fused aromatic ring; X can be NRX or CRXRY; if X═NRX then n is 1 or 2 and if X═CRXRY then n is 1; RX is selected from the group consisting of H, optionally substituted C1-20 alkyl, C5-20 aryl, C3-20 heterocyclyl, amido, thioamido, ester, acyl, and sulfonyl groups; RY is selected from H, hydroxy, amino; or RX and RY may together form a spiro-C3-7 cycloalkyl or heterocyclyl group; RC1 and RC2 are both hydrogen, or when X is CRXRY, RC1, RC2, RX and RY, together with the carbon atoms to which they are attached, may form an optionally substituted fused aromatic ring; and R1 is selected from H and halo.

## Background
This application is a continuation of U.S. patent application Ser. No. 12/109,260, filed on Apr. 24, 2008, now U.S. Pat. No. 7,981,889, which is a continuation of U.S. patent application Ser. No. 10/876,080, filed on Jun. 24, 2004 (now U.S. Pat. No. 7,449,464), which is a continuation-in-part of the U.S. patent application Ser. No. 10/799,154, filed on Mar. 12, 2004 (abandoned), which claims the benefit of prior filed U.S. Provisional Patent Application Nos. 60/454,995, filed on Mar. 14, 2003; 60/526,244, filed on Dec. 1, 2003; and 60/493,399 filed on Aug. 6, 2003, and further claims the foreign priority of Great Britain Patent Application No. 0305681.9, filed on Mar. 12, 2003, all of which are hereby incorporated by reference in their entireties.


The present invention relates to phthalazinone derivatives, and their use as pharmaceuticals. In particular, the present invention relates to the use of these compounds to inhibit the activity of the enzyme poly (ADP-ribose)polymerase, also known as poly(ADP-ribose)synthase and poly ADP-ribosyltransferase, and commonly referred to as PARP.
The mammalian enzyme PARP (a 113-kDa multidomain protein) has been implicated in the signalling of DNA damage through its ability to recognize and rapidly bind to DNA single or double strand breaks (D'Amours, et al., Biochem. J., 342, 249-268 (1999)).
Several observations have led to the conclusion that PARP participates in a variety of DNA-related functions including gene amplification, cell division, differentiation, apoptosis, DNA base excision repair and also effects on telomere length and chromosome stability (d'Adda di Fagagna, et al., Nature Gen., 23 (1), 76-80 (1999)).
Studies on the mechanism by which PARP modulates DNA repair and other processes has identified its importance in the formation of poly (ADP-ribose) chains within the cellular nucleus (Althaus, F. R. and Richter, C., ADP-Ribosylation of Proteins: Enzymology and Biological Significance, Springer-Verlag, Berlin (1987)). The DNA-bound, activated PARP utilizes NAD to synthesize poly (ADP-ribose) on a variety of nuclear target proteins, including topoisomerase, histones and PARP itself (Rhun, et al., Biochem. Biophys. Res. Commun., 245, 1-10 (1998))
Poly (ADP-ribosyl)ation has also been associated with malignant transformation. For example, PARP activity is higher in the isolated nuclei of SV40-transformed fibroblasts, while both leukemic cells and colon cancer cells show higher enzyme activity than the equivalent normal leukocytes and colon mucosa (Miwa, et al., Arch. Biochem. Biophys., 181, 313-321 (1977); Burzio, et al., Proc. Soc. Exp. Bioi. Med., 149, 933-938 (1975); and Hirai, et al., Cancer Res., 43, 3441-3446 (1983)).
A number of low-molecular-weight inhibitors of PARP have been used to elucidate the functional role of poly (ADP-ribosylation in DNA repair. In cells treated with alkylating agents, the inhibition of PARP leads to a marked increase in DNA-strand breakage and cell killing (Durkacz, et al., Nature, 283, 593-596 (1980); Berger, N. A., Radiation Research, 101, 4-14 (1985)).
Subsequently, such inhibitors have been shown to enhance the effects of radiation response by suppressing the repair of potentially lethal damage (Ben-Hur, et al., British Journal of Cancer, 49 (Suppl. VI), 34-42 (1984); Schlicker, et al., Int. J. Radiat. Bioi., 75, 91-100 (1999)). PARP inhibitors have been reported to be effective in radio sensitising hypoxic tumour cells (U.S. Pat. No. 5,032,617; U.S. Pat. No. 5,215,738 and U.S. Pat. No. 5,041,653).
Furthermore, PARP knockout (PARP −/−) animals exhibit genomic instability in response to alkylating agents and γ-irradiation (Wang, et al., Genes Dev., 9, 509-520 (1995); Menissier de Murcia, et al., Proc. Natl. Acad. Sci. USA, 94, 7303-7307 (1997)).
A role for PARP has also been demonstrated in certain vascular diseases, septic shock, ischaemic injury and neurotoxicity (Cantoni, et al., Biochim. Biophys. Acta, 1014, 1-7 (1989); Szabo, et al., J. Clin. Invest., 100, 723-735 (1997)). Oxygen radical DNA damage that leads to strand breaks in DNA, which are subsequently recognised by PARP, is a major contributing factor to such disease states as shown by PARP inhibitor studies (Cosi, et al., J. Neurosci. Res., 39, 38-46 (1994); Said, et al., Proc. Natl. Acad. Sci. U.S.A., 93, 4688-4692 (1996)). More recently, PARP has been demonstrated to play a role in the pathogenesis of haemorrhagic shock (Liaudet, et al., Proc. Natl. Acad. Sci. U.S.A., 97 (3), 10203-10208 (2000)).
It has also been demonstrated that efficient retroviral infection of mammalian cells is blocked by the inhibition of PARP activity. Such inhibition of recombinant retroviral vector infections was shown to occur in various different cell types (Gaken, et al., J. Virology, 70 (6), 3992-4000 (1996)). Inhibitors of PARP have thus been developed for the use in anti-viral therapies and in cancer treatment (WO 91/18591).
Moreover, PARP inhibition has been speculated to delay the onset of aging characteristics in human fibroblasts (Rattan and Clark, Biochem. Biophys. Res. Comm., 201 (2), 665-672 (1994)). This may be related to the role that PARP plays in controlling telomere function (d'Adda di Fagagna, et al., Nature Gen., 23 (1), 76-80 (1999)).
Some of the present inventors have previously described (WO 02/36576) a class of 1(2H)-phthalazinone compounds which act as PARP inhibitors. The compounds have the general formula:




where A and B together represent an optionally substituted, fused aromatic ring and where RCC is represented by -L-RL. A large number of examples are of the formula:





where R represent one or more optional substituents.

The present inventors have now discovered that compounds where R is of a certain nature exhibit surprising levels of inhibition of the activity of PARP, and/or of potentiation of tumour cells to radiotherapy and various chemotherapies.
Accordingly, the first aspect of the present invention provides a compound of the formula (I):




and isomers, salts, solvates, chemically protected forms, and prodrugs thereof

wherein:

A and B together represent an optionally substituted, fused aromatic ring;

X can be NRX or CRXRY;

if X═NRX then n is 1 or 2 and if X═CRXRY then n is 1;

RX is selected from the group consisting of H, optionally substituted C1-20 alkyl, C5-20 aryl, C3-20 heterocyclyl, amido, thioamido, ester, acyl, and sulfonyl groups;

RY is selected from H, hydroxy, amino;

or RX and RY may together form a spiro-C3-7 cycloalkyl or heterocyclyl group;

RC1 and RC2 are independently selected from the group consisting of hydrogen and C1-4 alkyl, or when X is CRXRY, RC1, RC2, RX and RY, together with the carbon atoms to which they are attached, may form an optionally substituted fused aromatic ring; and

R1 is selected from H and halo.

Therefore, if X is CRXRY, then n is 1 and the compound is of formula (Ia):




If X is NRX, and n is 1, the compound is of formula (Ib):




If X is NRX, and n is 2, the compound is of formula (Ic):




A second aspect of the present invention provides a pharmaceutical composition comprising a compound of the first aspect and a pharmaceutically acceptable carrier or diluent.
A third aspect of the present invention provides the use of a compound of the first aspect in a method of treatment of the human or animal body.
A fourth aspect of the present invention provides the use of a compound as defined in the first aspect of the invention in the preparation of a medicament for:
(a) inhibiting the activity of PARP (PARP-1 and/or PARP-2);
(b) the treatment of: vascular disease; septic shock; ischaemic injury, both cerebral and cardiovascular; reperfusion injury, both cerebral and cardiovascular; neurotoxicity, including acute and chronic treatments for stroke and Parkinsons disease; haemorraghic shock; inflammatory diseases, such as arthritis; multiple sclerosis; secondary effects of diabetes; as well as the acute treatment of cytoxicity following cardiovascular surgery or diseases ameliorated by the inhibition of the activity of PARP;

(c) use as an adjunct in cancer therapy or for potentiating tumour cells for treatment with ionizing radiation or chemotherapeutic agents.

In particular, compounds as defined in the first aspect of the invention can be used in anti-cancer combination therapies (or as adjuncts) along with alkylating agents, such as methyl methanesulfonate (MMS), temozolomide and dacarbazine (DTIC), also with topoisomerase-1 inhibitors like Irinotecan, Rubitecan, Exatecan, Lurtotecan, Gimetecan, Diflomotecan (homocamptothecins); as well as 7-substituted non-silatecans; the 7-silyl camptothecins, BNP 1350; and non-camptothecin topoisomerase-I inhibitors such as indolocarbazoles also dual topoisomerase-I and II inhibitors like the benzophenazines, XR 11576/MLN 576 and benzopyridoindoles. Such combinations could be given, for example, as intravenous preparations or by oral administration as dependent on the preferred method of administration for the particular agent.
Other further aspects of the invention provide for the treatment of disease ameliorated by the inhibition of PARP, comprising administering to a subject in need of treatment a therapeutically-effective amount of a compound as defined in the first aspect, preferably in the form of a pharmaceutical composition and the treatment of cancer, comprising administering to a subject in need of treatment a therapeutically-effective amount of a compound as defined in the first aspect in combination, preferably in the form of a pharmaceutical composition, simultaneously or sequentially with ionizing radiation or chemotherapeutic agents.
In further aspects of the present invention, the compounds may be used in the preparation of a medicament for the treatment of cancer which is deficient in Homologous Recombination (HR) dependent DNA double strand break (DSB) repair activity, or in the treatment of a patient with a cancer which is deficient in HR dependent DNA DSB repair activity, comprising administering to said patient a therapeutically-effective amount of the compound.
The HR dependent DNA DSB repair pathway repairs double-strand breaks (DSBs) in DNA via homologous mechanisms to reform a continuous DNA helix (K. K. Khanna and S. P. Jackson, Nat. Genet. 27 (3): 247-254 (2001)). The components of the HR dependent DNA DSB repair pathway include, but are not limited to, ATM (NM—000051), RAD51 (NM—002875), RAD51L1 (NM—002877), RAD51C (NM—002876), RAD51L3 (NM—002878), DMC1 (NM—007068), XRCC2 (NM—005431), XRCC3 (NM—005432), RAD52 (NM—002879), RAD54L (NM—003579), RAD54B (NM—012415), BRCA1 (NM—007295), BRCA2 (NM—000059), RAD50 (NM—005732), MRE11A (NM—005590) and NBS1 (NM—002485). Other proteins involved in the HR dependent DNA DSB repair pathway include regulatory factors such as EMSY (Hughes-Davies, et al., Cell, 115, pp 523-535). HR components are also described in Wood, et al., Science, 291, 1284-1289 (2001).
A cancer which is deficient in HR dependent DNA DSB repair may comprise or consist of one or more cancer cells which have a reduced or abrogated ability to repair DNA DSBs through that pathway, relative to normal cells i.e. the activity of the HR dependent DNA DSB repair pathway may be reduced or abolished in the one or more cancer cells.
The activity of one or more components of the HR dependent DNA DSB repair pathway may be abolished in the one or more cancer cells of an individual having a cancer which is deficient in HR dependent DNA DSB repair. Components of the HR dependent DNA DSB repair pathway are well characterised in the art (see for example, Wood, et al., Science, 291, 1284-1289 (2001)) and include the components listed above.
In some preferred embodiments, the cancer cells may have a BRCA1 and/or a BRCA2 deficient phenotype i.e. BRCA1 and/or BRCA2 activity is reduced or abolished in the cancer cells. Cancer cells with this phenotype may be deficient in BRCA1 and/or BRCA2, i.e. expression and/or activity of BRCA1 and/or BRCA2 may be reduced or abolished in the cancer cells, for example by means of mutation or polymorphism in the encoding nucleic acid, or by means of amplification, mutation or polymorphism in a gene encoding a regulatory factor, for example the EMSY gene which encodes a BRCA2 regulatory factor (Hughes-Davies, et al., Cell, 115, 523-535).
BRCA1 and BRCA2 are known tumour suppressors whose wild-type alleles are frequently lost in tumours of heterozygous carriers (Jasin M., Oncogene, 21 (58), 8981-93 (2002); Tutt, et al., Trends Mol Med., 8 (12), 571-6, (2002)). The association of BRCA1 and/or BRCA2 mutations with breast cancer is well-characterised in the art (Radice, P. J., Exp Clin Cancer Res., 21 (3 Supply, 9-12 (2002)). Amplification of the EMSY gene, which encodes a BRCA2 binding factor, is also known to be associated with breast and ovarian cancer.
Carriers of mutations in BRCA1 and/or BRCA2 are also at elevated risk of cancer of the ovary, prostate and pancreas.
In some preferred embodiments, the individual is heterozygous for one or more variations, such as mutations and polymorphisms, in BRCA1 and/or BRCA2 or a regulator thereof. The detection of variation in BRCA1 and BRCA2 is well-known in the art and is described, for example in EP 699 754, EP 705 903, Neuhausen, S. L. and Ostrander, E. A., Genet. Test, 1, 75-83 (1992); Chappnis, P. O. and Foulkes, W. D., Cancer Treat Res, 107, 29-59 (2002); Janatova M., et al., Neoplasma, 50 (4), 246-50 (2003); Jancarkova, N., Ceska Gynekol., 68 (1), 11-6 (2003)). Determination of amplification of the BRCA2 binding factor EMSY is described in Hughes-Davies, et al., Cell, 115, 523-535).
Mutations and polymorphisms associated with cancer may be detected at the nucleic acid level by detecting the presence of a variant nucleic acid sequence or at the protein level by detecting the presence of a variant (i.e. a mutant or allelic variant) polypeptide.
DEFINITIONS
The term “aromatic ring” is used herein in the conventional sense to refer to a cyclic aromatic structure, that is, a cyclic structure having delocalised n-electron orbitals.
The aromatic ring fused to the main core, i.e. that formed by -A-B-, may bear further fused aromatic rings (resulting in, e.g. naphthyl or anthracenyl groups). The aromatic ring(s) may comprise solely carbon atoms, or may comprise carbon atoms and one or more heteroatoms, including but not limited to, nitrogen, oxygen, and sulfur atoms. The aromatic ring(s) preferably have five or six ring atoms.
The aromatic ring(s) may optionally be substituted. If a substituent itself comprises an aryl group, this aryl group is not considered to be a part of the aryl group to which it is attached. For example, the group biphenyl is considered herein to be a phenyl group (an aryl group comprising a single aromatic ring) substituted with a phenyl group. Similarly, the group benzylphenyl is considered to be a phenyl group (an aryl group comprising a single aromatic ring) substituted with a benzyl group.
In one group of preferred embodiments, the aromatic group comprises a single aromatic ring, which has five or six ring atoms, which ring atoms are selected from carbon, nitrogen, oxygen, and sulfur, and which ring is optionally substituted. Examples of these groups include, but are not limited to, benzene, pyrazine, pyrrole, thiazole, isoxazole, and oxazole. 2-Pyrone can also be considered to be an aromatic ring, but is less preferred.
If the aromatic ring has six atoms, then preferably at least four, or even five or all, of the ring atoms are carbon. The other ring atoms are selected from nitrogen, oxygen and sulphur, with nitrogen and oxygen being preferred. Suitable groups include a ring with: no hetero atoms (benzene); one nitrogen ring atom (pyridine); two nitrogen ring atoms (pyrazine, pyrimidine and pyridazine); one oxygen ring atom (pyrone); and one oxygen and one nitrogen ring atom (oxazine).
If the aromatic ring has five ring atoms, then preferably at least three of the ring atoms are carbon. The remaining ring atoms are selected from nitrogen, oxygen and sulphur. Suitable rings include a ring with: one nitrogen ring atom (pyrrole); two nitrogen ring atoms (imidazole, pyrazole); one oxygen ring atom (furan); one sulphur ring atom (thiophene); one nitrogen and one sulphur ring atom (isothiazole, thiazole); and one nitrogen and one oxygen ring atom (isoxazole or oxazole).
The aromatic ring may bear one or more substituent groups at any available ring position. These substituents are selected from halo, nitro, hydroxy, ether, thiol, thioether, amino, C1-7 alkyl, C3-20 heterocyclyl and C5-20 aryl. The aromatic ring may also bear one or more substituent groups which together form a ring. In particular these may be of formula —(CH2)m— or —O—(CH2)p—O—, where m is 2, 3, 4 or 5 and p is 1, 2 or 3.
Alkyl: The term “alkyl” as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a carbon atom of a hydrocarbon compound having from 1 to 20 carbon atoms (unless otherwise specified), which may be aliphatic or alicyclic, and which may be saturated or unsaturated (e.g. partially unsaturated, fully unsaturated). Thus, the term “alkyl” includes the sub-classes alkenyl, alkynyl, cycloalkyl, cycloalkyenyl, cylcoalkynyl, etc., discussed below.
In the context of alkyl groups, the prefixes (e.g. C1-4, C1-7, C1-20, C2-7, C3-7, etc.) denote the number of carbon atoms, or range of number of carbon atoms. For example, the term “C1-4 alkyl”, as used herein, pertains to an alkyl group having from 1 to 4 carbon atoms. Examples of groups of alkyl groups include C1-4 alkyl (“lower alkyl”), C1-7 alkyl, and C1-20alkyl. Note that the first prefix may vary according to other limitations; for example, for unsaturated alkyl groups, the first prefix must be at least 2; for cyclic alkyl groups, the first prefix must be at least 3; etc.
Examples of (unsubstituted) saturated alkyl groups include, but are not limited to, methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5), hexyl (C6), heptyl (C7), octyl (C8), nonyl (C9), decyl (C10), undecyl (C11), dodecyl (C12), tridecyl (C13), tetradecyl (C14), pentadecyl (C15), and eicodecyl (C20).
Examples of (unsubstituted) saturated linear alkyl groups include, but are not limited to, methyl (C1), ethyl (C2), n-propyl (C3), n-butyl (C4), n-pentyl (amyl) (C5), n-hexyl (C6), and n-heptyl (C7).
Examples of (unsubstituted) saturated branched alkyl groups include, but are not limited to, iso-propyl (C3), iso-butyl (C4), sec-butyl (C4), tert-butyl (C4), iso-pentyl (C5), and neo-pentyl (C5).
Alkenyl: The term “alkenyl”, as used herein, pertains to an alkyl group having one or more carbon-carbon double bonds. Examples of alkenyl groups include C2-4 alkenyl, C2-7 alkenyl, C2-20 alkenyl.
Examples of (unsubstituted) unsaturated alkenyl groups include, but are not limited to, ethenyl (vinyl, —CH═CH2), 1-propenyl (—CH═CH—CH3), 2-propenyl (allyl, —CH—CH═CH2), isopropenyl (1-methylvinyl, —C(CH3)═CH2), butenyl (C4), pentenyl (C5), and hexenyl (C5).
Alkynyl: The term “alkynyl”, as used herein, pertains to an alkyl group having one or more carbon-carbon triple bonds. Examples of alkynyl groups include C2-4 alkynyl, C2-7 alkynyl, C2-20 alkynyl.
Examples of (unsubstituted) unsaturated alkynyl groups include, but are not limited to, ethynyl (ethinyl, —C═CH) and 2-propynyl (propargyl, —CH2—C═CH).
Cycloalkyl: The term “cycloalkyl”, as used herein, pertains to an alkyl group which is also a cyclyl group; that is, a monovalent moiety obtained by removing a hydrogen atom from an alicyclic ring atom of a carbocyclic ring of a carbocyclic compound, which carbocyclic ring may be saturated or unsaturated (e.g. partially unsaturated, fully unsaturated), which moiety has from 3 to 20 carbon atoms (unless otherwise specified), including from 3 to 20 ring atoms. Thus, the term “cycloalkyl” includes the sub-classes cycloalkenyl and cycloalkynyl. Preferably, each ring has from 3 to 7 ring atoms. Examples of groups of cycloalkyl groups include C3-20 cycloalkyl, C3-15 cycloalkyl, C3-10 cycloalkyl, C3-7 cycloalkyl.
Examples of cycloalkyl groups include, but are not limited to, those derived from:

    
    
        saturated monocyclic hydrocarbon compounds: cyclopropane (C3), cyclobutane (C4), cyclopentane (C5), cyclohexane (C6), cycloheptane (C7), methylcyclopropane (C4), dimethylcyclopropane (C5), methylcyclobutane (C5), dimethylcyclobutane (C6), methylcyclopentane (C6), dimethylcyclopentane (C7), methylcyclohexane (C7), dimethylcyclohexane (C8), menthane (C10);
        unsaturated monocyclic hydrocarbon compounds: cyclopropene (C3), cyclobutene (C4), cyclopentene (C5), cyclohexene (C6), methylcyclopropene (C4), dimethylcyclopropene (C5), methylcyclobutene (C5), dimethylcyclobutene (C6), methylcyclopentene (C6), dimethylcyclopentene (C7), methylcyclohexene (C7), dimethylcyclohexene (C8);
        saturated polycyclic hydrocarbon compounds: thujane (C10), carane (C10), pinane (C10), bornane (C10), norcarane (C7), norpinane (C7), norbornane (C7), adamantane (C10), decalin (decahydronaphthalene) (C10);
        unsaturated polycyclic hydrocarbon compounds: camphene (C10), limonene (C10), pinene (C10);
        polycyclic hydrocarbon compounds having an aromatic ring: indene (C9), indane (e.g., 2,3-dihydro-1H-indene) (C9), tetraline (1,2,3,4-tetrahydronaphthalene) (C10), acenaphthene (C12), fluorene (C13), phenalene (C13), acephenanthrene (C15), aceanthrene (C16), cholanthrene (C20).
    
    


Heterocyclyl: The term “heterocyclyl”, as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a ring atom of a heterocyclic compound, which moiety has from 3 to 20 ring atoms (unless otherwise specified), of which from 1 to 10 are ring heteroatoms. Preferably, each ring has from 3 to 7 ring atoms, of which from 1 to 4 are ring heteroatoms.
In this context, the prefixes (e.g. C3-20, C3-7, C5-6, etc.) denote the number of ring atoms, or range of number of ring atoms, whether carbon atoms or heteroatoms. For example, the term “C5-6heterocyclyl”, as used herein, pertains to a heterocyclyl group having 5 or 6 ring atoms. Examples of groups of heterocyclyl groups include C3-20 heterocyclyl, C5-20 heterocyclyl, C3-15 heterocyclyl, C5-15 heterocyclyl, C3-12 heterocyclyl, C5-12 heterocyclyl, C3-10 heterocyclyl, C5-10 heterocyclyl, C3-7 heterocyclyl, C5-7 heterocyclyl, and C5-6 heterocyclyl.
Examples of monocyclic heterocyclyl groups include, but are not limited to, those derived from:
N1: aziridine (C3), azetidine (C4), pyrrolidine (tetrahydropyrrole) (C5), pyrroline (e.g., 3-pyrroline, 2,5-dihydropyrrole) (C5), 2H-pyrrole or 3H-pyrrole (isopyrrole, isoazole) (C5), piperidine (C6), dihydropyridine (C6), tetrahydropyridine (C6), azepine (C7);

O1: oxirane (C3), oxetane (C4), oxolane (tetrahydrofuran) (C5), oxole (dihydrofuran) (C5), oxane (tetrahydropyran) (C6), dihydropyran (C6), pyran (C6), oxepin (C7);

S1: thiirane (C3), thietane (C4), thiolane (tetrahydrothiophene) (C5), thiane (tetrahydrothiopyran) (C5), thiepane (C7);

O2: dioxolane (C5), dioxane (C6), and dioxepane (C7);

O3: trioxane (C6);

N2: imidazolidine (C5), pyrazolidine (diazolidine) (C5), imidazoline (C5), pyrazoline (dihydropyrazole) (C5), piperazine (C6);

N1O1: tetrahydrooxazole (C5), dihydrooxazole (C5), tetrahydroisoxazole (C5), dihydroisoxazole (C5), morpholine (C5), tetrahydrooxazine (C6), dihydrooxazine (C6), oxazine (C6);

N1S1: thiazoline (C5), thiazolidine (C5), thiomorpholine (C6);

N2O1: oxadiazine (C6);

O1S1: oxathiole (C5) and oxathiane (thioxane) (C6); and,

N1O1S1: oxathiazine (C6).

Examples of substituted (non-aromatic) monocyclic heterocyclyl groups include those derived from saccharides, in cyclic form, for example, furanoses (C5), such as arabinofuranose, lyxofuranose, ribofuranose, and xylofuranse, and pyranoses (C6), such as allopyranose, altropyranose, glucopyranose, mannopyranose, gulopyranose, idopyranose, galactopyranose, and talopyranose.
Spiro-C3-7 cycloalkyl or heterocyclyl: The term “spiro C3-7 cycloalkyl or heterocyclyl” as used herein, refers to a C3-7 cycloalkyl or C3-7 heterocyclyl ring joined to another ring by a single atom common to both rings.
C5-20 aryl: The term “C5-20 aryl” as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from an aromatic ring atom of a C5-20 aromatic compound, said compound having one ring, or two or more rings (e.g., fused), and having from 5 to 20 ring atoms, and wherein at least one of said ring(s) is an aromatic ring. Preferably, each ring has from 5 to 7 ring atoms.
The ring atoms may be all carbon atoms, as in “carboaryl groups” in which case the group may conveniently be referred to as a “C5-20 carboaryl” group.
Examples of C5-20aryl groups which do not have ring heteroatoms (i.e. C5-20 carboaryl groups) include, but are not limited to, those derived from benzene (i.e. phenyl) (C6), naphthalene (C10), anthracene (C14), phenanthrene (C14), and pyrene (C16.
Alternatively, the ring atoms may include one or more heteroatoms, including but not limited to oxygen, nitrogen, and sulfur, as in “heteroaryl groups”. In this case, the group may conveniently be referred to as a “C5-20 heteroaryl” group, wherein “C5-20” denotes ring atoms, whether carbon atoms or heteroatoms. Preferably, each ring has from 5 to 7 ring atoms, of which from 0 to 4 are ring heteroatoms.
Examples of C5-20 heteroaryl groups include, but are not limited to, C5 heteroaryl groups derived from furan (oxole), thiophene (thiole), pyrrole (azole), imidazole (1,3-diazole), pyrazole (1,2-diazole), triazole, oxazole, isoxazole, thiazole, isothiazole, oxadiazole, tetrazole and oxatriazole; and C6 heteroaryl groups derived from isoxazine, pyridine (azine), pyridazine (1,2-diazine), pyrimidine (1,3-diazine; e.g., cytosine, thymine, uracil), pyrazine (1,4-diazine) and triazine.
The heteroaryl group may be bonded via a carbon or hetero ring atom.
Examples of C5-20heteroaryl groups which comprise fused rings, include, but are not limited to, C9heteroaryl groups derived from benzofuran, isobenzofuran, benzothiophene, indole, isoindole; C10 heteroaryl groups derived from quinoline, isoquinoline, benzodiazine, pyridopyridine; C14 heteroaryl groups derived from acridine and xanthene.
The above alkyl, heterocyclyl, and aryl groups, whether alone or part of another substituent, may themselves optionally be substituted with one or more groups selected from themselves and the additional substituents listed below.
Halo: —F, —Cl, —Br, and —I.
Hydroxy: —OH.
Ether: —OR, wherein R is an ether substituent, for example, a C1-7 alkyl group (also referred to as a C1-7 alkoxy group), a C3-20 heterocyclyl group (also referred to as a C3-20heterocyclyloxy group), or a C5-20 aryl group (also referred to as a C5-20aryloxy group), preferably a C1-7 alkyl group.

Nitro: —NO2.

Cyano (nitrile, carbonitrile): —CN.

Acyl (keto): —C(═O)R, wherein R is an acyl substituent, for example, H, a C1-7 alkyl group (also referred to as C1-7 alkylacyl or C1-7 alkanoyl), a C3-20 heterocyclyl group (also referred to as C3-20 heterocyclylacyl), or a C5-20 aryl group (also referred to as C5-20arylacyl), preferably a C1-7 alkyl group. Examples of acyl groups include, but are not limited to, —C(═O)CH3 (acetyl), —C(═O)CH2CH3 (propionyl), —C(═O)C(CH3)3 (butyryl), and —C(═O)Ph (benzoyl, phenone).

Carboxy (carboxylic acid): —COOH.

Ester (carboxylate, carboxylic acid ester, oxycarbonyl): —C(═O)OR, wherein R is an ester substituent, for example, a C1-7 alkyl group, a C3-20heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. 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.

Amido (carbamoyl, carbamyl, aminocarbonyl, carboxamide): —C(═O)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═O)NH2, —C(═O)NHCH3, —C(═O)N(CH3)2, —C(═O)NHCH2CH3, and —C(═O)N(CH2CH3)2, as well as amido groups in which R1 and R2, together with the nitrogen atom to which they are attached, form a heterocyclic structure as in, for example, piperidinocarbonyl, morpholinocarbonyl, thiomorpholinocarbonyl, and piperazinylcarbonyl.

Amino: —NR1R2, wherein R1 and R2 are independently amino substituents, for example, hydrogen, a C1-7 alkyl group (also referred to as C1-7 alkylamino or di-C1-7 alkylamino), a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably H or a C1-7 alkyl group, or, in the case of a “cyclic” amino group, R1 and R2, taken together with the nitrogen atom to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Examples of amino groups include, but are not limited to, —NH2, —NHCH3, —NHCH(CH3)2, —N(CH3)2, —N(CH2CH3)2, and —NHPh. Examples of cyclic amino groups include, but are not limited to, aziridinyl, azetidinyl, pyrrolidinyl, piperidino, piperazinyl, perhydrodiazepinyl, morpholino, and thiomorpholino. In particular, the cyclic amino groups may be substituted on their ring by any of the substituents defined here, for example carboxy, carboxylate and amido.

Acylamido (acylamino): —NR1C(═O)R2, wherein R1 is an amide substituent, for example, hydrogen, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably H or a C1-7 alkyl group, most preferably H, and R2 is an acyl substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of acylamide groups include, but are not limited to, —NHC(═O)CH3—NHC(═O)CH2CH3, and —NHC(═O)Ph. R1 and R2 may together form a cyclic structure, as in, for example, succinimidyl, maleimidyl, and phthalimidyl:





Ureido: —N(R1)CONR2R3 wherein R2 and R3 are independently amino substituents, as defined for amino groups, and R1 is a ureido substituent, for example, hydrogen, a C1-7alkyl group, a C3-20heterocyclyl group, or a C5-20aryl group, preferably hydrogen or a C1-7alkyl group. Examples of ureido groups include, but are not limited to, —NHCONH2, —NHCONHMe, —NHCONHEt, —NHCONMe2, —NHCONEt2, —NMeCONH2, —NMeCONHMe, —NMeCONHEt, —NMeCONMe2, —NMeCONEt2 and —NHCONHPh.

Acyloxy (reverse ester): —OC(═O)R, wherein R is an acyloxy substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. 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, —OC(═O)C6H4F, and —OC(═O)CH2Ph.

Thiol: —SH.

Thioether (sulfide): —SR, wherein R is a thioether substituent, for example, a C1-7 alkyl group (also referred to as a C1-7 alkylthio group), a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of C1-7 alkylthio groups include, but are not limited to, —SCH3 and —SCH2CH3.

Sulfoxide (sulfinyl): —S(═O)R, wherein R is a sulfoxide substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfoxide groups include, but are not limited to, —S(═O)CH3 and —S(═O)CH2CH3.

Sulfonyl (sulfone): —S(═O)2R, wherein R is a sulfone substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7alkyl group. Examples of sulfone groups include, but are not limited to, —S(═O)2CH3 (methanesulfonyl, mesyl), —S(═O)2CF3, —S(═O)2CH2CH3, and 4-methylphenylsulfonyl (tosyl).

Thioamido (thiocarbamyl): —C(═S)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═S)NH2, —C(═S)NHCH3, —C(═S)N(CH3)2, and —C(═S)NHCH2CH3.

Sulfonamino: —NR1S(═O)2R, wherein R1 is an amino substituent, as defined for amino groups, and R is a sulfonamino substituent, for example, a C1-7alkyl group, a C3-20heterocyclyl group, or a C5-20aryl group, preferably a C1-7alkyl group. Examples of sulfonamino groups include, but are not limited to, —NHS(═O)2CH3, —NHS(═O)2Ph and —N(CH3) S(═O)2C6H5.

As mentioned above, the groups that form the above listed substituent groups, e.g. C1-7 alkyl, C3-20 heterocyclyl and C5-20 aryl, may themselves be substituted. Thus, the above definitions cover substituent groups which are substituted.



BRIEF DESCRIPTION OF FIGURES
FIGS. 1A-B shows clonogenic survival curves of cells proficient and deficient in Braca 1 exposed to compound (4) of the present invention.
FIG. 1A shows Brca1 wild type (11CO:▪), heterozygous (Cre6:▴) and deficient (Cre10:●) embryonic fibroblastic stem (ES) cells under continuous exposure to compound 4. Error bars represent standard errors of the mean.
FIG. 1B shows Brca2 wild type (D3:▪), heterozygous (Cre6:▴) and deficient (Cre24:●) ES cells under continuous exposure to compound 4. Error bars represent standard errors of the mean.
FIG. 2 shows an analysis of the effects of a compound of the invention (4) in another cell line lacking BRCA2 function in comparison to a BRCA2 complemented line. Data shown is clonogenic survival of Brca2 deficient (V-C8:▪) and complemented (V-C8 BAC+:▴) cells under continuous exposure to compound 4 at varying concentrations.



FURTHER PREFERENCES
The following preferences can apply to each aspect of the present invention, where applicable.
In the present invention, the fused aromatic ring(s) represented by -A-B- preferably consist of solely carbon ring atoms, and thus may be benzene, naphthalene, and is more preferably benzene. As described above, these rings may be substituted, but in some embodiments are preferably unsubstituted.
If the fused aromatic ring represented by -A-B- bears a substituent group, it is preferably attached to the atom which itself is attached to the central ring meta- to the carbonyl group. Thus, if the fused aromatic ring is a benzene ring, the preferred place of substitution is shown in the formula below by *:




which is usually termed the 5-position of the phthalazinone moiety.

R1 is preferably selected from H, Cl and F, and is more preferably F.
It is preferred that RC1 and RC2 are independently selected from hydrogen and C1-4 alkyl, and more preferably H and methyl. It is more preferred that at least one of RC1 and RC2 are hydrogen, with the most preferred option being that both are hydrogen.
When n is 2, X is NRX. In these embodiments, RX is preferably selected from the group consisting of: H; optionally substituted C1-20 alkyl (for example, optionally substituted C5-20 arylmethyl); optionally substituted C5-20 aryl; optionally substituted ester groups, wherein the ester substituent is preferably C1-20 alkyl; optionally substituted acyl groups; optionally substituted amido groups; optionally substituted thioamido groups; and optionally substituted sulfonyl groups. RX is more preferably selected from the group consisting of: H; optionally substituted C1-20 alkyl; optionally substituted C5-20 aryl; and optionally substituted ester groups, wherein the ester substituent is preferably C1-20 alkyl.
When n is 1, X may be NRX or CRXCRY.
In embodiments where X is NRX, RX is preferably selected from the group consisting of: H; optionally substituted C1-20 alkyl (for example, optionally substituted C5-20 arylmethyl); optionally substituted C5-20 aryl; optionally substituted acyl; optionally substituted sulfonyl; optionally substituted amido; and optionally substituted thioamido groups.
In embodiments where X is CRXRY, RY is preferably H. RX is preferably selected from the group consisting of: H; optionally substituted C1-20 alkyl (for example, optionally substituted C5-20 arylmethyl); optionally substituted C5-20 aryl; optionally substituted C3-20 heterocyclyl; optionally substituted acyl, wherein the acyl substituent is preferably selected from C5-20 aryl and C3-20 heterocylyl (e.g. piperazinyl); optionally substituted amido, wherein the amino groups are preferably selected from H and C1-20 alkyl or together with the nitrogen atom, form a C5-20 heterocyclic group; and optionally substituted ester groups, wherein the ester substituent is preferably selected from C1-20 alkyl groups.
Particularly preferred compounds include: 1, 2, 3, 4, 10, 20, 59, 80, 135, 146, 192, 194, 195, 211 and 212.
Where appropriate, the above preferences may be taken in combination with each other.
Includes Other Forms
Included in the above are the well known ionic, salt, solvate, and protected forms of these substituents. For example, a reference to carboxylic acid (—COOH) also includes the anionic (carboxylate) form (—COO−), a salt or solvate thereof, as well as conventional protected forms. Similarly, a reference to an amino group includes the protonated form (—N+HR1R2), 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 (—O−), a salt or solvate thereof, as well as conventional protected forms of a hydroxyl group.
Isomers, Salts, Solvates, Protected Forms, and Prodrugs
Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diasterioisomeric, epimeric, 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; D- and L-forms; d- and l-forms; (+) and (−) forms; keto-, enol-, and enolate-forms; syn- and anti-forms; synclinal- and anticlinal-forms; α- and β-forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as “isomers” (or “isomeric forms”).
If the compound is in crystalline form, it may exist in a number of different polymorphic 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, —CH2OH. Similarly, a reference to ortho-chlorophenyl is not to be construed as a reference to its structural isomer, meta-chlorophenyl. However, a reference to a class of structures may well include structurally isomeric forms falling within that class (e.g., C1-7 alkyl includes n-propyl and iso-propyl; butyl includes n-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl).
The above exclusion does not pertain 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.
Particularly relevant to the present invention is the tautomeric pair illustrated below:




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 1H, 2H (D), and 3H (T); C may be in any isotopic form, including 12C, 13C, and 14C; O may be in any isotopic form, including 16O and 18O; 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, as well as its different polymorphic forms.
It may be convenient or desirable to prepare, purify, and/or handle a corresponding salt of the active compound, for example, a pharmaceutically-acceptable salt. Examples of pharmaceutically acceptable salts are discussed in Berge, et al., “Pharmaceutically Acceptable Salts”, J. Pharm. Sci., 66, 1-19 (1977).
For example, if the compound is anionic, or has a functional group which may be anionic (e.g., —COOH may be —COO−), then a salt may be formed with a suitable cation. Examples of suitable inorganic cations include, but are not limited to, alkali metal ions such as Na+ and K+, alkaline earth cations such as Ca3+ and Mg2+, and other cations such as 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+, NR4+). 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+.
If the compound is cationic, or has a functional group which may be cationic (e.g., —NH2 may be —NH3+), then a 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, hydrobromic, hydroiodic, sulfuric, sulfurous, nitric, nitrous, phosphoric, and phosphorous. Examples of suitable organic anions include, but are not limited to, those derived from the following organic acids: acetic, propionic, succinic, gycolic, stearic, palmitic, lactic, malic, pamoic, tartaric, citric, gluconic, ascorbic, maleic, hydroxymaleic, phenylacetic, glutamic, aspartic, benzoic, cinnamic, pyruvic, salicyclic, sulfanilic, 2-acetyoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethanesulfonic, ethane disulfonic, oxalic, isethionic, valeric, and gluconic. Examples of suitable polymeric anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl cellulose.
It may be convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the active compound. The term “solvate” is used herein in the conventional sense to refer to a complex of solute (e.g. active compound, salt of active compound) and solvent. If the solvent is water, the solvate may be conveniently referred to as a hydrate, for example, a mono-hydrate, a di-hydrate, a tri-hydrate, etc.
It may be convenient or desirable to prepare, purify, and/or handle the active compound in a chemically protected form. The term “chemically protected form,” as used herein, pertains to a compound in which one or more reactive functional groups are protected from undesirable chemical reactions, that is, are in the form of a protected or protecting group (also known as a masked or masking group or a blocked or blocking group). By protecting a reactive functional group, reactions involving other unprotected reactive functional groups can be performed, without affecting the protected group; the protecting group may be removed, usually in a subsequent step, without substantially affecting the remainder of the molecule. See, for example, “Protective Groups in Organic Synthesis” (T. Green and P. Wuts; 3rd Edition; John Wiley and Sons, 1999).
For example, a hydroxy group may be protected as an ether (—OR) or an ester (—OC(═O)R), for example, as: a t-butyl ether; a benzyl, benzhydryl (diphenylmethyl), or trityl (triphenylmethyl)ether; a trimethylsilyl or t-butyldimethylsilyl ether; or an acetyl ester (—OC(═O)CH3, —OAc).
For example, an aldehyde or ketone group may be protected as an acetal or ketal, respectively, in which the carbonyl group (>C═O) is converted to a diether (>C(OR)2), by reaction with, for example, a primary alcohol. The aldehyde or ketone group is readily regenerated by hydrolysis using a large excess of water in the presence of acid.
For example, an amine group may be protected, for example, as an amide or a urethane, for example, as: a methyl amide (—NHCO—CH3); a benzyloxy amide (—NHCO—OCH2C6H5, —NH-Cbz); as a t-butoxy amide (—NHCO—OC(CH3)3, —NH-Boc); a 2-biphenyl-2-propoxy amide (—NHCO—OC(CH3)2C6H4C6H5, —NH-Bpoc), as a 9-fluorenylmethoxy amide (—NH-Fmoc), as a 6-nitroveratryloxy amide (—NH-Nvoc), as a 2-trimethylsilylethyloxy amide (—NH-Teoc), as a 2,2,2-trichloroethyloxy amide (—NH-Troc), as an allyloxy amide (—NH-Alloc), as a 2(-phenylsulphonyl)ethyloxy amide (—NH-Psec); or, in suitable cases, as an N-oxide (>NO□).
For example, a carboxylic acid group may be protected as an ester for example, as: a C1-7 alkyl ester (e.g. a methyl ester; a t-butyl ester); a C1-7 haloalkyl ester (e.g. a C1-7 trihaloalkyl ester); a triC1-7alkylsilyl-C1-7 alkyl ester; or a C5-20 aryl-C1-7 alkyl ester (e.g. a benzyl ester; a nitrobenzyl ester); or as an amide, for example, as a methyl amide.
For example, a thiol group may be protected as a thioether (—SR), for example, as: a benzyl thioether; an acetamidomethyl ether (—S—CH2NHC(═O)CH3).
It may be convenient or desirable to prepare, purify, and/or handle the active compound in the form of a prodrug. The term “prodrug”, as used herein, pertains to a compound which, when metabolised (e.g. in vivo), yields the desired active compound. Typically, the prodrug is inactive, or less active than the active compound, but may provide advantageous handling, administration, or metabolic properties.
For example, some prodrugs are esters of the active compound (e.g. a physiologically acceptable metabolically labile ester). During metabolism, the ester group (—C(═O)OR) is cleaved to yield the active drug. Such esters may be formed by esterification, for example, of any of the carboxylic acid groups (—C(═O)OH) in the parent compound, with, where appropriate, prior protection of any other reactive groups present in the parent compound, followed by deprotection if required. Examples of such metabolically labile esters include, but are not limited to, those wherein R is C1-20 alkyl (e.g. -Me, -Et); C1-7 aminoalkyl (e.g. aminoethyl; 2-(N,N-diethylamino) ethyl; 2-(4-morpholino)ethyl); and acyloxy-C1-7 alkyl (e.g. acyloxymethyl; acyloxyethyl; e.g. pivaloyloxymethyl; acetoxymethyl; 1-acetoxyethyl; 1-(1-methoxy-1-methyl)ethyl-carbonxyloxyethyl; 1-(benzoyloxy)ethyl; isopropoxy-carbonyloxymethyl; 1-isopropoxy-carbonyloxyethyl; cyclohexyl-carbonyloxymethyl; 1-cyclohexyl-carbonyloxyethyl; cyclohexyloxy-carbonyloxymethyl; 1-cyclohexyloxy-carbonyloxyethyl; (4-tetrahydropyranyloxy) carbonyloxymethyl; 1-(4-tetrahydropyranyloxy)carbonyloxyethyl; (4-tetrahydropyranyl)carbonyloxymethyl; and 1-(4-tetrahydropyranyl)carbonyloxyethyl).
Further suitable prodrug forms include phosphonate and glycolate salts. In particular, hydroxy groups (—OH), can be made into phosphonate prodrugs by reaction with chlorodibenzylphosphite, followed by hydrogenation, to form a phosphonate group —O—P(═O)(OH)2. Such a group can be cleaved by phosphatase enzymes during metabolism to yield the active drug with the hydroxy group.
Also, some prodrugs are activated enzymatically to yield the active compound, or a compound which, upon further chemical reaction, yields the active compound. For example, the prodrug may be a sugar derivative or other glycoside conjugate, or may be an amino acid ester derivative.
Acronyms
For convenience, many chemical moieties are represented using well known abbreviations, including but not limited to, methyl (Me), ethyl (Et), n-propyl (nPr), iso-propyl (iPr), n-butyl (nBu), tert-butyl (tBu), n-hexyl (nHex), cyclohexyl (cHex), phenyl (Ph), biphenyl (biPh), benzyl (Bn), naphthyl (naph), methoxy (MeO), ethoxy (EtO), benzoyl (Bz), and acetyl (Ac).
For convenience, many chemical compounds are represented using well known abbreviations, including but not limited to, methanol (MeOH), ethanol (EtOH), iso-propanol (i-PrOH), methyl ethyl ketone (MEK), ether or diethyl ether (Et2O), acetic acid (AcOH), dichloromethane (methylene chloride, DCM), trifluoroacetic acid (TFA), dimethylformamide (DMF), tetrahydrofuran (THF), and dimethylsulfoxide (DMSO).
Synthesis
In the synthesis routes given below, the A-B fused ring is shown as a fused benzene ring for convenience. Compounds in which the A-B ring is other than benzene may be synthesised using methodologies analogous to those described below by the use of appropriate alternative starting materials.
Compounds of the present invention may be synthesised by reaction of a compound of Formula 1:




in which R1 is as previously defined, with a compound of Formula 2:





in which n, RC1, RC2 and X are as previously defined, in the presence of a coupling reagent system, for example 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate or (dimethylaminopropyl)ethylcarbodiimide hydrochloride/hydroxybenzotriazole, in the presence of a base, for example diisopropylethylamine, in a solvent, for example dimethylacetamide or dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Alternatively, compounds of the present invention may be synthesised by conversion of a compound of Formula 1 into an activated species, for example an acid chloride or an activated ester such as an N-hydroxysuccinimide ester, using well-known methodologies, and reaction of the activated species with a compound of Formula 2.
Compounds of Formula 1 may be synthesised by reaction of a compound of Formula 3:




in which R1 is as previously defined, or a compound of Formula 4:





in which R1 is as previously defined, or a mixture of a compound of Formula 3 and a compound of Formula 4, with a source of hydrazine, for example hydrazine hydrate, optionally in the presence of a base, for example triethylamine, optionally in the presence of a solvent, for example industrial methylated spirit, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 3 or Formula 4, or mixtures thereof, may be synthesised by reaction of a compound of Formula 5:




in which R1 is as previously defined, with a reagent capable of hydrolysing a nitrile moiety, for example sodium hydroxide, in the presence of a solvent, for example water, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 5 may be synthesised by reaction of a compound of Formula 6:




in which R1 is as previously defined, with a compound of Formula 7:





in the presence of a base, for example sodium methoxide, in a solvent, for example methanol, optionally in the presence of a water scavenger, for example ethyl propionate, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 1 may also be synthesised by reaction of a compound of Formula 8:




in which R1 is as previously defined, with a reagent capable of hydrolysing a nitrile moiety, for example sodium hydroxide, in the presence of a solvent, for example water, at a temperature in the range of 0° C. to the boiling point of the solvent used, followed by reaction of the resulting intermediate with a source of hydrazine, for example hydrazine hydrate, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 8 may be synthesised by reaction of a compound of Formula 9:




in which Ra is a C1-4 alkyl group, with a compound of Formula 6, in the presence of a base, for example triethylamine or lithium hexamethyldisilazide, in the presence of a solvent, for example tetrahydrofuran, at a temperature in the range of −80° C. to the boiling point of the solvent used.

Compounds of Formula 9 may be synthesised by methods analogous to those described in WO 02/26576.
Compounds of Formula 1 may also be synthesised by methods analogous to those described above in which the nitrile moiety in all Formulae is replaced by other moieties capable of generating a carboxylic acid, for example ester or carboxamide moieties.
Compounds of Formula 2 are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of the present invention in which X is CRXRY, in which one of RX or RY is an amido moiety, and which may therefore be represented by Formula 10:




in which n, RC1, RC2, R1 and RX are as previously defined and RN1 and RN2 are each individually selected from the group consisting of H, optionally substituted C1-20 alkyl, C5-20 aryl, C3-20 heterocyclyl, or may together form an optionally substituted C3-7 cycloalkyl or heterocyclyl group, may be synthesised by reaction of a compound of Formula 11:





in which n, RC1, RC2, R1 and RX are as previously defined, with a compound of Formula HNRN1RN2, in which RN! and RN2 are as previously defined, in the presence of a coupling reagent system, for example 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate or (dimethylaminopropyl)ethylcarbodiimide hydrochloride/hydroxybenzotriazole, in the presence of a base, for example diisopropylethylamine, in a solvent, for example dimethylacetamide or dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Alternatively, compounds of Formula 10 may be synthesised by conversion of a compound of Formula 11 into an activated species, for example an acid chloride or an activated ester such as an N-hydroxysuccinimide ester, using well-known methodologies, and reaction of the activated species with a compound of Formula HNRN1RN2.
Compounds of Formula 11 may be synthesised by deprotection of a protected form of a compound of Formula 11, for example a compound of Formula 12:




in which n, RC1, RC2, R1 and RX are as previously defined and R′′ is a C1-4 alkyl group, using well known methodologies, for example base-catalysed hydrolysis in the presence of a source of hydroxide, for example sodium or lithium hydroxide, in the presence of a solvent, for example water and/or tetrahydrofuran, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 12 may be synthesised from compounds of Formula 1 by the previously described methods.
Compounds of Formula HNRN1RN2 are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of the present invention in which X is NH and which may therefore be represented by Formula 13:




in which n, RC1, RC2 and R1 are as previously defined, may be synthesised by deprotection of a protected form of a compound of Formula 13, for example a compound of Formula 14:





in which n, RC1, RC2 and R1 are as previously defined, using well known methodologies, for example acid-catalysed cleavage, in the presence of an acid, for example trifluoroacetic acid or hydrochloric acid, in the presence of a solvent, for example dichloromethane or ethanol and/or water, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula 14 may be synthesised from compounds of Formula 1 by the previously described methods.
Compounds of the present invention in which X is NRX, in which RX is an acyl moiety, and which may therefore be represented by Formula 15:




in which n, RC1, RC2 and R1 are as previously defined and RC3 is selected from the group consisting of optionally substituted C1-20 alkyl, C5-20 aryl and C3-20 heterocyclyl, may be synthesised by reaction of a compound of Formula 13 with a compound of Formula RC3COX, in which RC3 is as previously defined and X is a suitable leaving group, for example a halogen such as chloro, optionally in the presence of a base, for example pyridine, triethylamine or diisopropylethylamine, optionally in the presence of a solvent, for example dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula RC3COX are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of Formula 15 may also be synthesised by reaction of a compound of Formula 13 with a compound of Formula RC3CO2H, in which RC3 is as previously defined, in the presence of a coupling reagent system, for example 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate or (dimethylaminopropyl)ethylcarbodiimide hydrochloride/hydroxybenzotriazole, in the presence of a base, for example diisopropylethylamine, in a solvent, for example dimethylacetamide or dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.
Compounds of Formula RC3CO2H are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of the present invention in which X is NRX, in which RX is an amido or thioamido moiety, and which may therefore be represented by Formula 16:




in which n, RC1, RC2 and R1 are as previously defined, Y is O or S and RN3 is selected from the group consisting of optionally substituted C1-20 alkyl, C5-20 aryl and C3-20 heterocyclyl, may be synthesised by reaction of a compound of Formula 13 with a compound of Formula RN3NCY, in which Y and RN3 are as previously defined, in the presence of a solvent, for example dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula RN3NCY are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of the present invention in which X is NRX, in which RX is a sulfonyl moiety, and which may therefore be represented by Formula 17:




in which n, RC1, RC2 and R1 are as previously defined and RS1 is selected from the group consisting of optionally substituted C1-20 alkyl, C5-20 aryl and C3-20 heterocyclyl, may be synthesised by reaction of a compound of Formula 13 with a compound of Formula RS1SO2Cl, in which RS1 is as previously defined, optionally in the presence of a base, for example pyridine, triethylamine or diisopropylethylamine, in the presence of a solvent, for example dichloromethane, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula RS1SO2Cl are commercially available or may be synthesised by methods reported in the chemical literature.
Compounds of the present invention in which X is NRX, in which RX is selected from the group consisting of optionally substituted C1-20 alkyl or C3-20 heterocyclyl, and which may therefore be represented by Formula 18:




in which n, RC1, RC2 and R1 are as previously defined and Rn and RC5 are each individually selected from the group consisting of H, optionally substituted C2-20 alkyl, C5-20 aryl, C3-20 heterocyclyl, or may together form an optionally substituted C3-7 cycloalkyl or heterocyclyl group, may be synthesised by reaction of a compound of Formula 13 with a compound of Formula RC4CORC5, in which RC4 and RC5 are as previously defined, in the presence of a reducing agent, for example sodium cyanoborohydride or sodium triacetoxyborohydride, in the presence of a solvent, for example methanol, optionally in the presence of an acid catalyst, for example acetic acid, at a temperature in the range of 0° C. to the boiling point of the solvent used.

Compounds of Formula RC4CORC5 are commercially available or may be synthesised by methods reported in the chemical literature.
Use
The present invention provides active compounds, specifically, active in inhibiting the activity of PARP.
The term “active” as used herein, pertains to compounds which are capable of inhibiting PARP activity, and specifically includes both compounds with intrinsic activity (drugs) as well as prodrugs of such compounds, which prodrugs may themselves exhibit little or no intrinsic activity.
One assay which may conveniently be used in order to assess the PARP inhibition offered by a particular compound is described in the examples below.
The present invention further provides a method of inhibiting the activity of PARP in a cell, comprising contacting said cell with an effective amount of an active compound, preferably in the form of a pharmaceutically acceptable composition. Such a method may be practised in vitro or in vivo.
For example, a sample of cells may be grown in vitro and an active compound brought into contact with said cells, and the effect of the compound on those cells observed. As examples of “effect”, the amount of DNA repair effected in a certain time may be determined. Where the active compound is found to exert an influence on the cells, this may be used as a prognostic or diagnostic marker of the efficacy of the compound in methods of treating a patient carrying cells of the same cellular type.
The term “treatment”, as used herein in the context of treating a condition, pertains generally to treatment and therapy, whether of a human or an animal (e.g. in veterinary applications), in which some desired therapeutic effect is achieved, for example, the inhibition of the progress of the condition, and includes a reduction in the rate of progress, a halt in the rate of progress, amelioration of the condition, and cure of the condition. Treatment as a prophylactic measure (i.e. prophylaxis) is also included.
The term “adjunct” as used herein relates to the use of active compounds in conjunction with known therapeutic means. Such means include cytotoxic regimens of drugs and/or ionising radiation as used in the treatment of different cancer types. In particular, the active compounds are known to potentiate the actions of a number of cancer chemotherapy treatments, which include the topoisomerase class of poisons and most of the known alkylating agents used in treating cancer.
Active compounds may also be used as cell culture additives to inhibit PARP, for example, in order to sensitize cells to known chemotherapeutic agents or ionising radiation treatments in vitro.
Active compounds may also be used as part of an in vitro assay, for example, in order to determine whether a candidate host is likely to benefit from treatment with the compound in question.
Administration
The active compound or pharmaceutical composition comprising the active compound may be administered to a subject by any convenient route of administration, whether systemically/peripherally or at the site of desired action, including but not limited to, oral (e.g. by ingestion); topical (including e.g. transdermal, intranasal, ocular, buccal, and sublingual); pulmonary (e.g. by inhalation or insufflation therapy using, e.g. an aerosol, e.g. through mouth or nose); rectal; vaginal; parenteral, for example, by injection, including subcutaneous, intradermal, intramuscular, intravenous, intraarterial, intracardiac, intrathecal, intraspinal, intracapsular, subcapsular, intraorbital, intraperitoneal, intratracheal, subcuticular, intraarticular, subarachnoid, and intrasternal; by implant of a depot, for example, subcutaneously or intramuscularly.
The subject may be a eukaryote, an animal, a vertebrate animal, a mammal, a rodent (e.g. a guinea pig, a hamster, a rat, a mouse), murine (e.g. a mouse), canine (e.g. a dog), feline (e.g. a cat), equine (e.g. a horse), a primate, simian (e.g. a monkey or ape), a monkey (e.g. marmoset, baboon), an ape (e.g. gorilla, chimpanzee, orangutang, gibbon), or a human.
Formulations
While it is possible for the active compound to be administered alone, it is preferable to present it as a pharmaceutical composition (e.g., formulation) comprising at least one active compound, as defined above, together with one or more pharmaceutically acceptable carriers, adjuvants, excipients, diluents, fillers, buffers, stabilisers, preservatives, lubricants, or other materials well known to those skilled in the art and optionally other therapeutic or prophylactic agents.
Thus, the present invention further provides pharmaceutical compositions, as defined above, and methods of making a pharmaceutical composition comprising admixing at least one active compound, as defined above, together with one or more pharmaceutically acceptable carriers, excipients, buffers, adjuvants, stabilisers, or other materials, as described herein.
The term “pharmaceutically acceptable” as used herein pertains to compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of a subject (e.g. human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, excipient, etc. must also be “acceptable” in the sense of being compatible with the other ingredients of the formulation.
Suitable carriers, diluents, excipients, etc. can be found in standard pharmaceutical texts. See, for example, “Handbook of Pharmaceutical Additives”, 2nd Edition (eds. M. Ash and I. Ash), 2001 (Synapse Information Resources, Inc., Endicott, N.Y., USA), “Remington's Pharmaceutical Sciences”, 20th edition, pub. Lippincott, Williams & Wilkins, 2000; and “Handbook of Pharmaceutical Excipients”, 2nd edition, 1994.
The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active compound with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active compound with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product.
Formulations may be in the form of liquids, solutions, suspensions, emulsions, elixirs, syrups, tablets, losenges, granules, powders, capsules, cachets, pills, ampoules, suppositories, pessaries, ointments, gels, pastes, creams, sprays, mists, foams, lotions, oils, boluses, electuaries, or aerosols.
Formulations suitable for oral administration (e.g., by ingestion) may be presented as discrete units such as capsules, cachets or tablets, each containing a predetermined amount of the active compound; as a powder or granules; as a solution or suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion; as a bolus; as an electuary; or as a paste.
A tablet may be made by conventional means, e.g. compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active compound in a free-flowing form such as a powder or granules, optionally mixed with one or more binders (e.g. povidone, gelatin, acacia, sorbitol, tragacanth, hydroxypropylmethyl cellulose); fillers or diluents (e.g. lactose, microcrystalline cellulose, calcium hydrogen phosphate); lubricants (e.g. magnesium stearate, talc, silica); disintegrants (e.g. sodium starch glycolate, cross-linked povidone, cross-linked sodium carboxymethyl cellulose); surface-active or dispersing or wetting agents (e.g., sodium lauryl sulfate); and preservatives (e.g., methyl p-hydroxybenzoate, propyl p-hydroxybenzoate, sorbic acid). Molded tablets may be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active compound therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.
Formulations suitable for topical administration (e.g. transdermal, intranasal, ocular, buccal, and sublingual) may be formulated as an ointment, cream, suspension, lotion, powder, solution, past, gel, spray, aerosol, or oil. Alternatively, a formulation may comprise a patch or a dressing such as a bandage or adhesive plaster impregnated with active compounds and optionally one or more excipients or diluents.
Formulations suitable for topical administration in the mouth include losenges comprising the active compound in a flavored basis, usually sucrose and acacia or tragacanth; pastilles comprising the active compound in an inert basis such as gelatin and glycerin, or sucrose and acacia; and mouthwashes comprising the active compound in a suitable liquid carrier.
Formulations suitable for topical administration to the eye also include eye drops wherein the active compound is dissolved or suspended in a suitable carrier, especially an aqueous solvent for the active compound.
Formulations suitable for nasal administration, wherein the carrier is a solid, include a coarse powder having a particle size, for example, in the range of about 20 to about 500 microns which is administered in the manner in which snuff is taken, i.e. by rapid inhalation through the nasal passage from a container of the powder held close up to the nose. Suitable formulations wherein the carrier is a liquid for administration as, for example, nasal spray, nasal drops, or by aerosol administration by nebuliser, include aqueous or oily solutions of the active compound.
Formulations suitable for administration by inhalation include those presented as an aerosol spray from a pressurised pack, with the use of a suitable propellant, such as dichlorodifluoromethane, trichlorofluoromethane, dichoro-tetrafluoroethane, carbon dioxide, or other suitable gases.
Formulations suitable for topical administration via the skin include ointments, creams, and emulsions. When formulated in an ointment, the active compound may optionally be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active compounds may be formulated in a cream with an oil-in-water cream base. If desired, the aqueous phase of the cream base may include, for example, at least about 30% w/w of a polyhydric alcohol, i.e., an alcohol having two or more hydroxyl groups such as propylene glycol, butane-1,3-diol, mannitol, sorbitol, glycerol and polyethylene glycol and mixtures thereof. The topical formulations may desirably include a compound which enhances absorption or penetration of the active compound through the skin or other affected areas. Examples of such dermal penetration enhancers include dimethylsulfoxide and related analogues.
When formulated as a topical emulsion, the oily phase may optionally comprise merely an emulsifier (otherwise known as an emulgent), or it may comprises a mixture of at least one emulsifier with a fat or an oil or with both a fat and an oil. Preferably, a hydrophilic emulsifier is included together with a lipophilic emulsifier which acts as a stabiliser. It is also preferred to include both an oil and a fat. Together, the emulsifier(s) with or without stabiliser(s) make up the so-called emulsifying wax, and the wax together with the oil and/or fat make up the so-called emulsifying ointment base which forms the oily dispersed phase of the cream formulations.
Suitable emulgents and emulsion stabilisers include Tween 60, Span 80, cetostearyl alcohol, myristyl alcohol, glyceryl monostearate and sodium lauryl sulphate. The choice of suitable oils or fats for the formulation is based on achieving the desired cosmetic properties, since the solubility of the active compound in most oils likely to be used in pharmaceutical emulsion formulations may be very low. Thus the cream should preferably be a non-greasy, non-staining and washable product with suitable consistency to avoid leakage from tubes or other containers. Straight or branched chain, mono- or dibasic alkyl esters such as di-isoadipate, isocetyl stearate, propylene glycol diester of coconut fatty acids, isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate, 2-ethylhexyl palmitate or a blend of branched chain esters known as Crodamol CAP may be used, the last three being preferred esters. These may be used alone or in combination depending on the properties required. Alternatively, high melting point lipids such as white soft paraffin and/or liquid paraffin or other mineral oils can be used.
Formulations suitable for rectal administration may be presented as a suppository with a suitable base comprising, for example, cocoa butter or a salicylate.
Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active compound, such carriers as are known in the art to be appropriate.
Formulations suitable for parenteral administration (e.g., by injection, including cutaneous, subcutaneous, intramuscular, intravenous and intradermal), include aqueous and non-aqueous isotonic, pyrogen-free, sterile injection solutions which may contain anti-oxidants, buffers, preservatives, stabilisers, bacteriostats, and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents, and liposomes or other microparticulate systems which are designed to target the compound to blood components or one or more organs. Examples of suitable isotonic vehicles for use in such formulations include Sodium Chloride Injection, Ringer's Solution, or Lactated Ringer's Injection. Typically, the concentration of the active compound in the solution is from about 1 ng/ml to about 10 μg/ml, for example from about 10 ng/ml to about 1 μg/ml. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules, and tablets. Formulations may be in the form of liposomes or other microparticulate systems which are designed to target the active compound to blood components or one or more organs.
Dosage
It will be appreciated that appropriate dosages of the active compounds, and compositions comprising the active compounds, can vary from patient to patient. Determining the optimal dosage will generally involve the balancing of the level of therapeutic benefit against any risk or deleterious side effects of the treatments of the present invention. The selected dosage level will depend on a variety of factors including, but not limited to, the activity of the particular compound, the route of administration, the time of administration, the rate of excretion of the compound, the duration of the treatment, other drugs, compounds, and/or materials used in combination, and the age, sex, weight, condition, general health, and prior medical history of the patient. The amount of compound and route of administration will ultimately be at the discretion of the physician, although generally the dosage will be to achieve local concentrations at the site of action which achieve the desired effect without causing substantial harmful or deleterious side-effects.
Administration in vivo can be effected in one dose, continuously or intermittently (e.g., in divided doses at appropriate intervals) throughout the course of treatment. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used for therapy, the purpose of the therapy, the target cell being treated, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician.
In general, a suitable dose of the active compound is in the range of about 100 μg to about 250 mg per kilogram body weight of the subject per day. Where the active compound is a salt, an ester, prodrug, or the like, the amount administered is calculated on the basis of the parent compound and so the actual weight to be used is increased proportionately.
Synthesis Data
General Experimental Methods
Preparative HPLC
Samples were purified with a Waters mass-directed purification system utilising a Waters 600 LC pump, Waters Xterra C18 column (5 μm 19 mm×50 mm) and Micromass ZQ mass spectrometer, operating in positive ion electrospray ionisation mode. Mobile phases A (0.1% formic acid in water) and B (0.1% formic acid in acetonitrile) were used in a gradient; 5% B to 100% over 7 min, held for 3 min, at a flow rate of 20 ml/min.
Analytical HPLC-MS
Analytical HPLC was typically carried out with a Spectra System P4000 pump and Jones Genesis C18 column (4 μm, 50 mm×4.6 mm). Mobile phases A (0.1% formic acid in water) and B (acetonitrile) were used in a gradient of 5% B for 1 min rising to 98% B after 5 min, held for 3 min at a flow rate of 2 ml/min. Detection was by a TSP UV 6000LP detector at 254 nm UV and range 210-600 nm PDA. The Mass spectrometer was a Finnigan LCQ operating in positive ion electrospray mode.
NMR
1H NMR and 13C NMR were typically recorded using Bruker DPX 300 spectrometer at 300 MHz and 75 MHz respectively. Chemical shifts were reported in parts per million (ppm) on the δ scale relative to tetramethylsilane internal standard. Unless stated otherwise all samples were dissolved in DMSO-d6.
Synthesis of Key Intermediates
a. 3-(4-Oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A)




A mixture of 27% sodium methoxide solution in methanol (400 g, 2 mol) and methanol (150 ml) was added dropwise between ambient temperature and 30° C. over 15 minutes to a stirred mixture of phthalide (67 g, 0.5 mol), 3-formylbenzonitrile (65.5 g, 0.5 mol) and ethyl propionate (250 ml), the mixture was stirred at ambient temperature for 40 minutes and at reflux temperature for 1 hour, then it was allowed to cool to ambient temperature. The resulting red solid was collected by filtration, washed with ethyl acetate (2×50 ml) and dissolved in water (1800 ml). The solution was acidified by the addition of acetic acid (60 ml) and the resulting red solid was collected by filtration, washed with water (2×200 ml) and dried in vacuo to give 3-(1,3-dioxoindan-2-yl)benzonitrile (83.2 g) as a dark red solid, m.pt. 179-182° C., m/z (M+H)+. 248, which was used without further purification.
3-(1,3-Dioxoindan-2-yl)benzonitrile (74.18 g, 0.3 mol) was added in portions to a solution of sodium hydroxide (36 g, 0.9 mol) in water (580 ml), the resulting dark red suspension was stirred at reflux temperature for 5 hours, then it was cooled to ambient temperature and washed with ethyl acetate (3×300 ml). The aqueous solution was acidified by the dropwise addition of concentrated hydrochloric acid (110 ml), the mixture was stirred at ambient temperature for 1 hour, then the resulting solid was collected by filtration, washed with water (2×200 ml) and dried in vacuo to give a 1:1 mixture of 3-(1,3-dioxoindan-2-yl)benzoic acid, (M+H)+. 267, and 2-[2-(3-carboxyphenyl)acetyl]benzoic acid, (M+H)+. 285, (69.32 g), which was used without further purification.
The mixture obtained in the previous step (52.8 g) was added to a solution of triethylamine (37.55 g, 0.372 mol) in industrial methylated spirit (500 ml) and the resulting cloudy solution was filtered through a pad of filter-aid to give a clear solution. Hydrazine monohydrate (9.3 g, 0.186 mol) was added in one portion at ambient temperature, the stirred mixture was heated under reflux for 1 hour, then it was concentrated in vacuo to approximately 250 ml and added to a solution of sodium acetate (41 g, 0.5 mol) in water (500 ml). The mixture was brought to pH 7 by the dropwise addition of concentrated hydrochloric acid, then it was stirred at ambient temperature for 3 hours. The resulting solid was collected by filtration, washed with water (50 ml) and dried in vacuo to give a white solid (15.62 g). The combined filtrate and washings were acidified to pH 6 by the addition of hydrochloric acid, then the mixture was stirred at ambient temperature for 3 hours. The resulting solid was collected by filtration, washed with water (50 ml) and dried in vacuo to give a second crop of off-white solid (17.57 g). The combined filtrate and washings from the second crop were readjusted to pH 6 and treated as before to give a third crop of pale orange solid (6.66 g). The three crops were combined to give essentially pure 3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A), (M+H)+. 281, δH 4.4 (2H, s), 7.2-7.4 (1H, m), 7.5-7.6 (1H, m), 7.7-8.0 (5H, m), 8.1-8.2 (1H, m), 12.6 (1H, s)
b. 2-Fluoro-5-(4-oxo-3,4-dihydro-phthalazin-1-ylmethyl)benzoic acid (B)




Dimethyl phosphite (22.0 g, 0.2 mol) was added drop-wise to a solution of sodium methoxide (43.0 g) in methanol (100 ml) at 0° C. 2-Carboxybenzaldehyde (21.0 g, 0.1 mol) was then added portion-wise to the reaction mixture as a slurry in methanol (40 ml), with the temperature kept below 5° C. The resulting pale yellow solution was warmed to 20° C. over 1 hour. Methanesulphonic acid (21.2 g, 0.22 mol) was added to the reaction drop-wise and the resulting white suspension was evaporated in vacuo. The white residue was quenched with water and extracted into chloroform (3×100 ml). The combined organic extracts were washed with water (2×100 ml), dried over MgSO4, and evaporated in vacuo to yield (3-oxo-1,3-dihydro-isobenzofuran-1-yl)phosphonic acid dimethyl ester as a white solid (32.0 g, 95%, 95% purity). This was then used without further purification in the next stage.
To a mixture of (3-oxo-1,3-dihydro-isobenzofuran-1-yl)phosphonic acid dimethyl ester (35.0 g, 0.14 mol) in tetrahydrofuran (200 ml) and 2-fluoro-5-formylbenzonitrile (20.9 g, 0.14 mol) in tetrahydrofuran (130 ml) was added triethylamine (14 ml, 0.14 mol) drop-wise over 25 min, with the temperature kept below 15° C. The reaction mixture was warmed slowly to 20° C. over 1 hour and concentrated in vacuo. The white residue was slurried in water (250 ml) for 30 minutes, filtered, washed with water, hexane and ether, and dried to yield 2-fluoro-5-(3-oxo-3H-isobenzofuran-1-ylidenemethyl)benzonitrile as a 50:50 mixture of E and Z isomers (37.2 g, 96%); m/z [M+1]+ 266 (98% purity)
To a suspension of 2-fluoro-5-(3-oxo-3H-isobenzofuran-1-ylidenemethyl)benzonitrile in water (200 ml) was added aqueous sodium hydroxide (26.1 g in 50 ml water) solution and the reaction mixture was heated under nitrogen to 90° C. for 30 minutes. The reaction mixture was partially cooled to 70° C., and hydrazine hydrate (100 ml) was added and stirred for 18 hours at 70° C. The reaction was cooled to room temperature and acidified with 2M HCl to pH 4. The mixture was stirred for 10 min and filtered. The resulting solid was washed with water, hexane, ether, ethyl acetate and dried to yield 2-fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid as a pale pink powder (30.0 g, 77%). m/z [M+1]+ 299 (96% purity), δH 4.4 (2H, s), 7.2-7.3 (1H, m), 7.5-7.6 (1H, m), 7.8-8.0 (4H, m), 8.2-8.3 (1H, m), 12.6 (1H, s).
c. 1-[3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]piperidine-4-carboxylic acid (C)




3-(4-Oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A) (7.0 g, 0.25 mol), ethyl isonipecotate (5 ml, 0.32 mol), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) (12.3 g, 0.32 mol) and N,N,-diisopropylethylamine (10.0 ml, 0.55 mol) were added to dimethylacetamide (40 ml) and stirred for 18 h. Water (100 ml) was added to the reaction mixture and the product was extracted into dichloromethane (4×50 ml). The combined organic layers were washed with water (3×100 ml), dried over MgSO4, filtered and evaporated in vacuo to yield an oil. To a solution of the oil in tetrahydrofuran (100 ml) was added 10% aqueous sodium hydroxide solution (20 ml) and the reaction was stirred for 18 hours. The reaction was concentrated, washed with ethyl acetate (2×30 ml) and acidified with 2M HCl to pH 2. The aqueous layer was extracted with dichloromethane (2×100 ml), then the extracts were dried over MgSO4, filtered and evaporated to yield 1-[3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]piperidine-4-carboxylic acid (C) as a yellow solid (7.0 g, 65%), m/z [M+1]+ 392 (96% purity), δH 1.3-1.8 (5H, m), 2.8-3.1 (4H, m), 4.4 (2H, s), 7.2-7.3 (1H, m), 7.3-7.4 (1H, m), 7.7-8.0 (5H, m), 8.2-8.3 (1H, m), 12.6 (1H, s).
d. 1-[2-Fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]piperidine-4-carboxylic acid (D)




2-Fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (B)(3.1 g, 0.14 mol), ethyl isonipecotate (1.7 ml, 0.11 mol), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) (5.1 g, 0.13 mol) and N,N,-diisopropylethylamine (10.0 ml, 0.55 mol) were added to dimethylacetamide (15 ml) and stirred for 18 hours. Water (100 ml) was added to the reaction mixture and the product was extracted into dichloromethane (4×50 ml). The combined organic layers were, filtered, washed with water (3×100 ml), dried over MgSO4, filtered and evaporated in vacuo to yield an orange oil. The oil was purified by flash chromatography (ethyl acetate) to yield 1-[2-fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]piperidine-4-carboxylic acid as the methyl ester (1.5 g, 33%, 96% purity). To a solution of the methyl ester in tetrahydrofuran:water (2:1, 40 ml) was added sodium hydroxide (0.3 g, 0.075 mol) and the reaction was stirred for 18 h. The reaction was concentrated, washed with ethyl acetate (2×20 ml) and acidified with 2M HCl to pH 2. The aqueous layer was extracted with dichloromethane (2×20 ml), and the combined extracts were dried over MgSO4 and evaporated to yield 1-[3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]piperidine-4-carboxylic acid (D) as a yellow solid (0.6 g, 65%), m/z [M+1]+ 392 (96% purity)
EXAMPLE 1
a. Synthesis of 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1)




3-(4-Oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A)(5.0 g, 0.17 mol), tert-butyl 1-piperazinecarboxylate (3.9 g, 0.21 mol), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) (8.6 g, 0.22 mol) and N,N,-diisopropylethylamine (6.7 ml, 0.38 mol) were added to dimethylacetamide (40 ml) and stirred for 18 hours. Water (100 ml) was added and the reaction mixture was heated to 100° C. for 1 hour. The suspension was cooled to room temperature, filtered and dried to yield a white solid. The solid was dissolved in a solution of 6M HCl and ethanol (2:1, 50 ml) and stirred for 1 hour. The reaction was concentrated, basified with ammonia to pH 9, and the product was extracted into dichloromethane (2×50 ml). The combined organic layers were washed with water (2×50 ml), dried over MgSO4, and evaporated in vacuo to yield 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1) as a yellow crystalline solid (4.0 g, 77%); m/z [M+1]+ 349 (97% purity), δH 2.6-3.8 (8H, m), 4.4 (2H, s), 7.2-7.5 (4H, m), 7.7-8.0 (3H, m), 8.2-8.3 (1H, m), 12.6 (1H, s)
b. Synthesis of 4-[4-Fluoro-3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (2)




The synthesis was carried out according to the method described in (a) above using 2-fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (B) to yield 4-[4-fluoro-3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (2) as a white crystalline solid (4.8 g, 76%); m/z [M+1]+ 367 (97% purity), δH 2.6-3.8 (8H, m), 4.4 (2H, s), 7.2-7.5 (3H, m), 7.7-8.0 (3H, m), 8.2-8.3 (1H, m), 12.6 (1H, s).
c. Synthesis of 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3)




The synthesis was carried out according to the method described in (a) above using 3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A) and tert-butyl 1-homopiperazine carboxylate to yield 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3) as a grey crystalline solid (5.3 g, 97%); m/z [M+1]+ 363 (97% purity); δH 2.6-3.8 (10H, m), 4.4 (2H, s), 7.2-7.5 (4H, m), 7.7-8.0 (3H, m), 8.2-8.3 (1H, m), 12.6 (1H, s).
d. Synthesis of 4-[3-([1,4]diazepane-1-carbonyl)-4-fluorobenzyl]-2H-phthalazin-1-one (4)




The synthesis was carried out according to the method described in (a) above using 2-fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (B) and tert-butyl 1-homopiperazinecarboxylate to yield 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (4) as a yellow crystalline solid (5.3 g, 68%); m/z [M+1]+ 381 (97% purity); δH 2.6-3.8 (10H, m), 4.4 (2H, s), 7.2-7.5 (3H, m), 7.7-8.0 (3H, m), 8.2-8.3 (1H, m), 12.6 (1H, s).
EXAMPLE 2
a. 4-{3-[4-(6-Chlorobenzothiazol-2-yl)-1,4-diazepan-1-ylcarbonyl]benzyl}-1(2H)-phthalazinone




2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (150 mg, 0.47 mmol), diisopropylethylamine (102 mg, 0.8 mmol) and 6-chloro-2-(1,4-diazepan-1-yl)-1,3-benzothiazole (115 mg, 0.43 mmol) were added sequentially at ambient temperature to a stirred solution of 3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A) (100 mg, 0.36 mmol) in dry dimethylacetamide (1 ml), the mixture was stirred at ambient temperature for 1 hour and allowed to stand at ambient temperature for 16 hours, then it was added dropwise to stirred cold water (10 ml). After 30 minutes, the resulting solid was collected by filtration, washed with water (2×1 ml) and hexane (1 ml), dried in vacuo and purified using preparative HPLC to give the desired compound (5)(166 mg) as a grey solid; HPLC purity 90%; HPLC Retention time 4.21 minutes; m/z (M+H)+. 530.
b. The following compounds were synthesised in a manner analogous to that described in (a) above, but using appropriate alternative amine starting materials.
















 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





 6




4.18
508
90


 


 7




3.22
551
90


 


 8




4.13
508
90


 


 9




3.95
483
90


 


 10




3.79
465
90


 


 11




3.76
406
90


 


219




2.80
407
90

























 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





12 (Note 1)




3.56
494
100


 


13




3.71
451
90


 


14




4.39
538
90


 


15




3.66
498
90


 


16




4.33
533
90





Note 1:


12 did not require purification via preparative scale


HPLC-the product from the reaction was essentially pure.






















 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





17




4.64
526
90


 


18




3.99
482
90


 


19




4.00
452
90


 


20




4.15
466
90









EXAMPLE 3
a. 4-{3-[4-(4-fluorophenyl)piperazin-1-ylcarbonyl]benzyl}-1(2H)-phthalazinone (21)




2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (150 mg, 0.47 mmol), diisopropylethylamine (102 mg, 0.8 mmol) and 1-(4-fluorophenyl)piperazine (65 mg, 0.47 mmol) were added sequentially at ambient temperature to a stirred solution of 3-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A)(100 mg, 0.36 mmol) in dry dimethylacetamide (1 ml), the mixture was stirred at ambient temperature for 4 hours and allowed to stand at ambient temperature for 16 hours, then it was added dropwise to stirred cold water (10 ml). After 30 minutes, the resulting solid was collected by filtration, washed with water (2×1 ml) and hexane (1 ml), dried in vacuo and purified using preparative HPLC to give 4-{3-[4-(4-fluorophenyl)piperazin-1-ylcarbonyl]benzyl}-1(2H)-phthalazinone (21)(76 mg) as a cream solid; m/z (M+H)+. 443; HPLC Purity 90%; HPLC Retention time 4.00 minutes.
b. The following compounds were synthesised in a manner analogous to that described in (a) above, but using appropriate alternative amine starting materials.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





22




4.00
470
90


 


23




4.26
486
90


 


24




3.18
504
85


 


25




3.78
473
90


 


26




4.46
583
90


 


27




4.96
509
90


 


28




3.73
511
90


 


29




3.78
553
90


 


30




3.71
459
90


 


31




3.94
546
90


 


32




3.84
485
90


 


33




4.37
552
90


 


34




3.77
485
90


 


220 (Note 2)




2.89
440
100





Note 2:


220 did not require purification via preparation scale


HPLC-the product from the reaction was essentially pure.






EXAMPLE 4
1-[3-(4-oxo-3,4-dihydro-phthalazin-1-ylmethyl)-benzoyl]-piperidine-4-carboxylic acid (C) (0.24 mmol) was added to a solution of the appropriate amine (0.2 mmol) in dimethylacetamide (2 ml). 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (0.3 mmol) and Hunigs base (0.4 mmol) were then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





 











35




4.39
572
90


 


36




3.71
496
90


 


37




3.63
474
80


 


38




3.76
474
90


 


39




3.56
502
90


 


40




3.58
568
90


 


41




3.81
508
90


 


42




4.39
531
90


 


43




3.52
460
85


 


44




3.77
508
90


 


45




3.59
488
90


 


46




3.83
488
90


 


47




3.85
488
90


 


48




3.47
448
90


 


49




3.36
446
90


 


50




3.77
488
90


 


51




3.74
472
90


 


52




3.82
498
90


 


53




3.52
460
90


 


54




3.86
510
90


 


55




3.75
546
90


 


56




3.01
565
90


 


57




3.93
549
90


 


373




4.17
663
90


 


374




3.08
595
90


 


375




4.16
551
90


 


376




4.3
565
90


 


377




4.1
571
90


 


378




3.64
567
90


 


379




3.62
579
90


 


380




4.27
605
90


 


381




3.89
555
90


 


382




3.84
565
90


 


3.83




2.92
565
90


 


3.84




3.02
543
90









EXAMPLE 5
The appropriate sulphonyl chloride (0.24 mmol) was added to a solution of 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1) (0.2 mmol) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





58




3.85
504
90


 


59




3.44
442
90


 


60




4.09
558
90


 


61




3.93
525
90


 


62




3.73
543
90


 


63




4.38
532
90


 


64




3.76
509
90


 


65




3.82
470
90









EXAMPLE 6
The appropriate acid chloride (0.24 mmol) was added to a solution of 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1) (0.2 mmol) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC


Com-

(mi-

Purity


pound
R
nutes)
M + 1
(%)














66




4.04
530
85


 


67




3.71
460
90


 


68




3.69
506
90


 


69




3.19
450
85


 


70




3.44
478
90


 


71




3.94
538
90


 


72




3.68
526
90


 


73




3.6
464
90


 


74




3.63
472
90


 


75




3.73
535
80


 


76




3.49
530
90


 


77




3.5
512
85


 


78




3.52
459
90


 


79




4.01
588
90


 


80




4.05
406
90


 


81




3.84
513
90


 


82




4.07
520
90


 


83




4.41
671
90


 


84




3.62
582
90


 


85




3.82
508
90


 


86




3.81
507
90


 


87




3.33
445
90


 


88




4.08
571
90


 


89




3.67
480
90


 


90




3.54
577
90


 


91




3.49
498
90


 


92




4.04
510
90


 


93




3.75
512
90


 


94




3.67
482
90


 


95




3.54
474
90


 


96




3.52
537
90


 


97




4.13
475
90


 


98




3.8
512
85


 


99




4.09
544
90


 


100




3.63
486
90


 


101




3.91
502
90


 


102




3.61
511
90


 


103




3.57
474
90


 


104




3.67
504
90


 


105




4.02
508
90


 


106




3.81
500
90


 


107




4.11
540
90


 


108




4.19
560
90


 


109




3.61
468
90


 


110




3.69
582
90


 


111




3.85
549
85


 


112




4.37
573
90


 


113




3.84
496
90


 


114




3.62
573
90


 


115




3.72
500
90


 


116




3.8
500
85


 


117




3.9
496
90


 


118




4.03
560
90


 


119




4.16
560
90


 


120




4.71
472
80


 


121




3.47
526
90


 


122




3.78
632
90


 


123




3.27
506
90


 


124




3.92
590
90


 


125




4.76
706
90


 


126




4.27
605
90


 


127




3.71
557
90


 


128




3.98
551
90


 


129




3.9
496
90


 


130




3.57
454
90


 


131




3.21
450
90


 


132




3.61
446
90


 


133




3.39
418
85


 


134




3.81
494
90


 


135




3.31
418
90


 


136




3.38
444
90


 


137




3.56
506
85


 


138




3.48
484
90


 


139




3.84
510
90


 


140




3.56
472
90


 


141




3.34
476
90


 


142




3.56
490
90


 


143




3.53
488
90


 


144




3.99
523
90


 


145




3.7
468
90


 


192




3.11
392
90


 


350




3.16
462
90


 


351




2.77
474
90









EXAMPLE 7
The appropriate isocyanate (0.24 mmol) was added to a solution of 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1) (0.2 mmol) in dichloromethane (2 ml). The reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














146




3.34
435
85


 


147




3.76
483
90


 


148




3.49
449
90


 


149




3.57
487
90


 


150




4.03
537
90


 


151




3.77
519
85


 


152




3.72
487
90


 


153




3.57
505
90


 


154




4.08
537
80


 


155




3.68
497
85


 


156




4.03
553
90


 


157




3.93
497
90


 


158




3.62
494
90


 


159




3.68
497
90


 


160




3.73
475
90


 


161




3.9
513
90


 


162




4.11
511
90


 


163




3.58
483
90


 


164




3.71
517
90


 


165




3.34
435
85


 


166




3.7
497
90


 


167




3.56
513
90


 


168




4.04
552
90


 


169




4
547
90


 


170




3.54
507
90


 


171




3.42
497
90


 


172




3.95
552
90


 


173




3.79
541
85


 


174




3.66
529
90


 


175




3.92
527
85


 


176




3.62
527
90


 


177




4.28
569
90


 


178




3.81
610
90


 


352




3.73
555
90


 


353




3.79
541
90









EXAMPLE 8
The appropriate isothiocyanate (0.24 mmol) was added to a solution of 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1) (0.2 mmol) in dichloromethane (2 ml). The reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 















LC


Com-

LC RT

Purity


pound
R
(minutes)
M + 1
(%)














179




3.68
515
90


 


180




4.05
513
90


 


181




3.94
465
90


 


182




3.55
449
90


 


183




4.21
575
90


 


184




3.79
543
90


 


185




4.28
557
85


 


186




3.63
527
90


 


187




3.18
528
90


 


188




3.32
423
90


 


189




3.69
485
80


 


190




3.68
515
90


 


191




3.72
503
90


 


354




4.67
542
90


 


355




3.96
543
90









EXAMPLE 9
3-(4-Oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (A) (0.24 mmol) was added to a solution of the appropriate amine (0.2 mmol) in dimethylacetamide (2 ml). 2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (0.3 mmol) and Hunigs base (0.4 mmol) were then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





193
*—CH3
2.72
378
90


 


221




2.77
407
90

























 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














194




2.96
427
90


 


195




4.08
444
90


 


196




3.9
456
95


 


197




3.83
450
95


 


198




2.98
432
90


 


199




4.17
440
90


 


200




2.9
449
90


 


201




4.31
460
90


 


202




3.63
468
90


 


203




3.78
456
90


 


204




3.08
378
90

























 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





205




2.88
432
90


 


206




3.61
421
95


 


207




3.96
397
90


 


356




4.34
564
90


 


357




3.84
554
90









EXAMPLE 10
2-Fluoro-5-(4-oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoic acid (B) (0.24 mmol) was added to a solution of the appropriate amine (0.2 mmol) in dimethylacetamide (2 ml). 2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (0.3 mmol) and Hunigs base (0.4 mmol) were then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














208
*—CH3
2.8
396
90


 


359




2.78
425
85

























 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














209




3.9
456
95


 


210




3.97
467
90


 


211




2.84
426
90


 


212
*—CH3
3.46
368
90


 


222




5.07
461
90


 


223




4.46
511
90


 


224




2.96
499
90


 


225




3.55
445
85


 


226




4.19
457
90


 


227




4.34
471
90


 


228




2.88
466
90


 


229




4.23
477
90


 


230




4.03
473
90


 


231




3.07
500
90


 


232




3.92
473
90


 


233




4.55
471
90


 


234




4.32
477
90


 


235




3.94
443
90


 


236




4.03
461
90


 


237




2.69
411
90


 


238




2.76
438
90


 


239




2.77
494
90


 


240




2.91
444
90


 


358




4.59
472
90

























 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





213




3.81
439
90


 


214




3.95
415
90

























 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





360




4.08
472
90









EXAMPLE 11
An appropriate aldehyde (0.2 mmol) and 4-[3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (1)(0.24 mmol) were dissolved in dichloromethane (2 ml). Sodium triacetoxyborohydride (0.28 mmol) and glacial acetic acid (6.0 mmol) were then added and stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





215




2.89
406
90


 


216




2.91
406
90


 


217




3.16
493
90


 


218




3.09
479
90


 


361




2.98
419
90


 


362




2.74
377
90


 


363




3.04
419
90


 


364




2.82
391
85


 


365




2.84
403
90


 


366




2.96
419
90


 


367




3.15
445
90


 


368




3.04
419
90


 


369




2.75
391
85









EXAMPLE 12
An appropriate aldehyde (0.2 mmol) and 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (4)(0.24 mmol) were dissolved in dichloromethane (2 ml). Sodium triacetoxyborohydride (0.28 mmol) and glacial acetic acid (6.0 mmol) were then added and stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





241




2.9
437
90


 


242




3.05
451
90


 


243




2.84
409
90


 


244




3.12
465
90


 


245




3.16
451
90


 


246




2.86
423
90


 


247




2.89
435
90


 


248




3.04
451
90


 


249




3.23
477
90


 


250




3.09
451
90


 


370




2.80
423
90









EXAMPLE 13
An appropriate aldehyde (0.2 mmol) and 4-[4-fluoro-3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (2)(0.24 mmol) were dissolved in dichloromethane (2 ml). Sodium triacetoxyborohydride (0.28 mmol) and glacial acetic acid (6.0 mmol) were then added and stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














251




2.97
423
90


 


252




3.06
437
90


 


253




2.8
395
90


 


254




3.11
451
90


 


255




3.09
437
90


 


256




2.87
409
90


 


257




2.89
421
90


 


258




3.01
437
90


 


259




3.14
463
90


 


260




3.08
437
90


 


261




2.83
458
90


 


262




3.04
464
90


 


263




2.79
409
90









EXAMPLE 14
The appropriate acid chloride (0.24 mmol) was added to a solution of 4-[4-fluoro-3-(piperazine-1-carbonyl)benzyl]-2H-phthalazin-1-one (2) (0.2 mmol) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC 

LC 


Com-

RT

Purity


pound
R
(minutes)
M + 1
(%)





264
*—CH3
3.89
409
90


 


265




4.17
462
85


 


266




4.04
423
90


 


267




4.03
417
90


 


268




3.19
480
90


 


269




2.84
492
90


 


270




2.71
521
90


 


271




2.83
508
90


 


272




2.86
478
90


 


273




2.63
521
90









EXAMPLE 15
An appropriate aldehyde (0.2 mmol) and 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3)(0.24 mmol) were dissolved in dichloromethane (2 ml). Sodium triacetoxyborohydride (0.28 mmol) and glacial acetic acid (6.0 mmol) were then added and stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





274




2.92
419
90


 


275




3.04
433
90


 


276




2.78
391
90


 


277




3.09
433
90


 


278




2.86
405
90


 


279




2.88
417
90


 


280




2.99
433
90


 


281




3.11
459
90


 


282




3.06
433
90


 


283




2.93
443
90


 


284




2.92
451
90


 


285




2.99
459
90


 


286




2.94
441
90


 


287




3.36
589
85


 


288




2.72
487
85


 


289




3.24
499
90


 


290




3.14
497
90


 


291




3.9
483
85


 


292




3.22
493
90


 


293




2.91
419
90


 


294




3.08
511
90


 


295




2.92
443
90


 


296




3.03
478
90


 


297




3.48
501
90


 


298




3.93
545
90


 


299




3.06
456
90


 


300




3.8
483
90


 


301




3.08
472
90


 


302




3.22
506
90


 


303




3.13
522
90


 


304




3.29
533
90


 


305




3.39
589
90


 


306




3.07
492
90


 


307




3.41
589
90


 


308




2.87
460
85


 


309




3.06
496
90


 


310




3.13
513
90


 


311




2.96
459
90


 


312




2.98
453
90


 


313




3.09
501
90


 


314




2.76
405
90









EXAMPLE 16
The appropriate sulphonyl chloride (0.24 mmol) was added to a solution of 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3) (0.2 mmol) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC 

LC 


Com-

RT

Purity


pound
R
(minutes)
M + 1
(%)





315




4.15
571
90


 


316




4.36
579
90


 


317




3.68
483
90


 


371




3.71
523
90









EXAMPLE 17
The appropriate acid chloride (0.24 mmol) was added to a solution of 4-[(3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 











Compound
R
LC RT (minutes)
M + 1
LC Purity (%)





318




3.84
533
90


 


319




3.23
458
90


 


320




3.63
532
90


 


321




3.61
525
90


 


322




3.63
495
90


 


323




3.62
513
90


 


324
*—CN
3.16
415
90


 


325




3.52
459
90


 


326




3.95
489
90


 


327




3.89
549
90


 


328




4.00
557
90









EXAMPLE 18
The appropriate isocyanate (0.24 mmol) was added to a solution of 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3) (0.2 mmol) in dichloromethane (2 ml). The reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)














329




3.4
512
90


 


330




3.95
550
90


 


331




3.76
510
90


 


332




3.58
526
90


 


333




4.04
582
90









EXAMPLE 19
The appropriate isothiocyanate (0.24 mmol) was added to a solution of 4-[3-([1,4]diazepane-1-carbonyl)benzyl]-2H-phthalazin-1-one (3) (0.2 mmol) in dichloromethane (2 ml). The reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.
















 













LC 

LC 


Com-

RT

Purity


pound
R
(minutes)
M + 1
(%)














334




3.86
512
90


 


335




3.75
516
90


 


336




3.66
556
90


 


337




3.57
540
90


 


338




4.17
569
90


 


339




3.56
540
90


 


340




3.1
541
90


 


341




3.84
498
90


 


342




3.64
556
90


 


343




3.53
528
90


 


344




3.92
556
90


 


345




4.09
566
90


 


346




3.64
516
90


 


347




3.57
528
90


 


348




3.78
512
90


 


349




3.62
512
90









EXAMPLE 20
The appropriate acid chloride (0.24 mmol) was added to a solution of 4-[3-([1,4]diazepane-1-carbonyl)-4-fluorobenzyl]-2H-phthalazin-1-one (4) in dichloromethane (2 ml). Hunigs base (0.4 mmol) was then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.


















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





372




2.81
466
80


 


385




3.19
495
90









EXAMPLE 21
1-[2-Fluoro-5-(4-Oxo-3,4-dihydrophthalazin-1-ylmethyl)benzoyl]-piperidine-4-carboxylic acid (D) (0.24 mmol) was added to a solution of the appropriate amine (0.2 mmol) in dimethylacetamide (2 ml). 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (0.3 mmol) and Hunigs base (0.4 mmol) were then added and the reaction was stirred at room temperature for 16 hours. The reaction mixtures were then purified by preparative HPLC.
The compounds synthesised are set out below.


















 













LC RT

LC Purity


Compound
R
(minutes)
M + 1
(%)





386




3.21
480
90









EXAMPLE 22
In order to assess the inhibitory action of the compounds, the following assay was used to determine IC50 values (Dillon, et al., JBS., 8 (3), 347-352 (2003)).
Mammalian PARP, isolated from Hela cell nuclear extract, was incubated with Z-buffer (25 mM Hepes (Sigma); 12.5 mM MgCl2 (Sigma); 50 mM KCl (Sigma); 1 mM DTT (Sigma); 10% Glycerol (Sigma) 0.001% NP-40 (Sigma); pH 7.4) in 96 well FlashPlates (TRADE MARK) (NEN, UK) and varying concentrations of said inhibitors added. All compounds were diluted in DMSO and gave final assay concentrations of between 10 and 0.01 μM, with the DMSO being at a final concentration of 1% per well. The total assay volume per well was 40 μl.
After 10 minutes incubation at 30° C. the reactions were initiated by the addition of a 10 μl reaction mixture, containing NAD (5 μM), 3H-NAD and 30mer double stranded DNA-oligos. Designated positive and negative reaction wells were done in combination with compound wells (unknowns) in order to calculate % enzyme activities. The plates were then shaken for 2 minutes and incubated at 30° C. for 45 minutes.
Following the incubation, the reactions were quenched by the addition of 50 μl 30% acetic acid to each well. The plates were then shaken for 1 hour at room temperature.
The plates were transferred to a TopCount NXT (TRADE MARK) (Packard, UK) for scintillation counting. Values recorded are counts per minute (cpm) following a 30 second counting of each well.
The % enzyme activity for each compound is then calculated using the following equation:




  
    %
    ⁢
    
      
    
    ⁢
    Inhibition
  
  =
  
    100
    -
    
      (
      
        100
        ×
        
          
            (
            
              
                cpm
                ⁢
                
                  
                
                ⁢
                of
                ⁢
                
                  
                
                ⁢
                unknowns
              
              -
              
                mean
                ⁢
                
                  
                
                ⁢
                negative
                ⁢
                
                  
                
                ⁢
                cpm
              
            
            )
          
          
            (
            
              
                mean
                ⁢
                
                  
                
                ⁢
                positive
                ⁢
                
                  
                
                ⁢
                cpm
              
              -
              
                mean
                ⁢
                
                  
                
                ⁢
                negative
                ⁢
                
                  
                
                ⁢
                cpm
              
            
            )
          
        
      
      )
    
  




IC50 values (the concentration at which 50% of the enzyme activity is inhibited) were calculated, which are determined over a range of different concentrations, normally from 10 μM down to 0.001 μM. Such IC50 values are used as comparative values to identify increased compound potencies.
All compounds tested had a IC50 of less than 0.1 μM.
The following compounds have an IC50 of less than 0.01 μM: 2-5, 9, 10, 12-20, 24, 26-28, 30, 32-35, 38, 39, 42, 44-47, 49, 51, 58-68, 80-82, 84, 86, 88-90, 94-97, 100-105, 113-116, 121-123, 126, 132, 136, 138-140, 142-144, 147, 149, 151, 152, 156, 158, 159, 161-164, 166-175, 177-180, 182-184, 186-190, 194, 199, 202, 205, 207, 208, 213, 221-223, 225, 233-236, 239-274, 277, 279, 287, 288, 292, 293, 301-303, 306, 315, 316, 318-323, 325, 327-336, 338-350, 352-357, 359, 361, 363, 365 and 367-370.
The following compounds, as well as those above, have an IC50 of less than 0.02 μM: 1, 6-8, 11, 21-23, 25, 31, 36, 37, 40, 41, 43, 48, 52-54, 56, 57, 69-79, 83, 87, 91-93, 98, 99, 106, 109, 110, 111, 117, 118, 120, 124, 128-130, 133-135, 137, 141, 145, 146, 148, 150, 153-155, 157, 160, 165, 176, 181, 185, 191, 192, 195, 196, 197, 201, 203, 204, 206, 211, 212, 215-217, 219, 220, 224, 226, 227, 229-232, 237, 238, 275, 276, 278, 281-286, 289-291, 294, 295, 297-299, 304, 305, 307-309, 311, 314, 317, 324, 326, 337, 351, 358, 360, 362, 364, 366, 371 and 372.
The Potentiation Factor (PF50) for compounds is calculated as a ratio of the IC50 of control cell growth divided by the IC50 of cell growth+PARP inhibitor. Growth inhibition curves for both control and compound treated cells are in the presence of the alkylating agent methyl methanesulfonate (MMS). The test compounds were used at a fixed concentration of 0.2 micromolar. The concentrations of MMS were over a range from 0 to 10 μg/ml.
Cell growth was assessed using the sulforhodamine B (SRB) assay (Skehan, P., et al., (1990) New colorimetric cytotoxicity assay for anticancer-drug screening. J. Natl. Cancer Inst. 82, 1107-1112). 2,000 HeLa cells were seeded into each well of a flat-bottomed 96-well microtiter plate in a volume of 100 μl and incubated for 6 hours at 37° C. Cells were either replaced with media alone or with media containing PARP inhibitor at a final concentration of 0.5, 1 or 5 Cells were allowed to grow for a further 1 hour before the addition of MMS at a range of concentrations (typically 0, 1, 2, 3, 5, 7 and 10 μg/ml) to either untreated cells or PARP inhibitor treated cells. Cells treated with PARP inhibitor alone were used to assess the growth inhibition by the PARP inhibitor.
Cells were left for a further 16 hours before replacing the media and allowing the cells to grow for a further 72 hours at 37° C. The media was then removed and the cells fixed with 100 μl of ice cold 10% (w/v) trichloroacetic acid. The plates were incubated at 4° C. for 20 minutes and then washed four times with water. Each well of cells was then stained with 100 μl of 0.4% (w/v) SRB in 1% acetic acid for 20 minutes before washing four times with 1% acetic acid. Plates were then dried for 2 hours at room temperature. The dye from the stained cells was solubilized by the addition of 100 μl of 10 mM Tris Base into each well. Plates were gently shaken and left at room temperature for 30 minutes before measuring the optical density at 564 nM on a Microquant microtiter plate reader.
All the compounds tested had a PF50 at 200 nM of at least 2.0.
EXAMPLE 23
To assess the stand alone activity of a PARP inhibitor on Braca 1 and 2 deficient cells the following protocols were used.
Small Molecule Inhibitors of PARP:
Compound (4) was dissolved in DMSO at 10 mM and stored at −20° C. in the dark.
Cell Lines
VC8 cells and the mouse Brca2 BAC complemented derivatives were as described in M. Kraakman-van der Zwet, et al., Mol Cell Biol 22, 669-79 (2002)). ES cells defective in Brca2 function have been described previously (Tutt, et al., EMBO Rep 3, 255-60 (2002)). The construction of ES cells defective in Brca1 will be described elsewhere but have previously been validated (Foray, et al., Embo J, 22, 2860-71 (2003)).
Clonogenic Assays
For measurement of cellular sensitivity to a PARP inhibitor (compound 4), cell cultures in exponential growth were trypsinised and seeded at various densities in 6-well plates onto Mitomycin C inactivated mouse embryonic fibroblasts and where appropriate treated with the test compound after 18 hours. For continuous exposure, cells were re-fed every 4 days with fresh medium and inhibitor. After 10-14 days, cells were washed with PBS, fixed in methanol and stained with crystal violet. Colonies containing greater than approximately 50 cells were counted. Experiments were performed at least three times in triplicate.
Results
Reduction in the viability of BRCA1 and BRCA2 deficient cells Compound 4 was used to probe the sensitivity of cells deficient in Brca1 or Brca2 to the inhibition of PARP activity. Clonogenic assays showed that both Brca1 and Brca2 deficient cell lines were extremely sensitive to compound 4 compared to otherwise isogenic cells (FIG. 1A, 1B). The SF50 (dosage at which 50% of cells survived) for Compound 4 was 1.5×10−8M for cells deficient in Brca1, whilst the SF50 for matched wild type cells was 7×10−6M (FIG. 1A). This represents a factor of 467 fold enhanced sensitivity of Brca1 mutant cells compared to wild type cells.
The SF50 for Compound 4 was 1.2×10−8M for cells deficient in Brca2 whilst the SF50 for matched wild type cells was 1.8×10−5M (FIG. 1B). This represents a factor of 1,500 fold enhanced sensitivity of Brca2 mutant cells compared to wild type cells. Similar results were obtained with Chinese hamster ovary cells deficient in Brca2 (VC8) compared to a Brca2-complemented derivative (VC8-BAC)(FIG. 2). The SF50 for Compound 4 was 5×10−8M for the Brca2 deficient VC8 line whilst the SF50 for matched control, VC8-BAC, was 3×105M (FIG. 2). This represents a factor of 600 fold enhanced sensitivity of Brca2 mutant cells compared to wild type cells.

## Claims

1. A method of treatment for breast or ovarian cancer deficient in a HR dependent DNA DSB repair pathway comprising administering to a subject a therapeutically effective amount of a compound of formula (Ib):



or an isomer or salt thereof, or a mixture of any thereof, wherein:
A and B together represent a fused aromatic ring, optionally substituted with one or more substituent groups selected from halo, nitro, hydroxyl, ether, thiol, thioether, amino, C1-7 alkyl, C5-20 aryl and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur;
RX is selected from H, C1-20 alkyl, C5-20 aryl, amido, thioamido, ester, acyl, sulfonyl groups and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur, wherein the acyl, C1-20 alkyl, C5-20 aryl or heterocyclyl group is optionally substituted with one or more substituent groups selected from C1-20 alkyl, C5-20 aryl, halo, hydroxyl, ether, nitro, cyano, acyl, carboxy, ester, amido, amino, acylamido, ureido, acyloxy, thiol, thioether, sulfoxide, sulfonyl, thioamido, sulfonamido and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur;
RC1 and RC2 are both hydrogen; and
R1 is selected from H and halo;
wherein the cancer is breast cancer or ovarian cancer; and
wherein the cancer comprises one or more cancer cells having a reduced or abrogated ability to repair DNA DSB by HR relative to normal cells.

2. The method of claim 1, wherein the fused aromatic ring represented by A and B together is benzene.

3. The method of claim 1, wherein R1 is selected from H, Cl, and F.

4. The method of claim 1, wherein RX is selected from H, C1-20 alkyl, C5-20 aryl, acyl, sulfonyl, amido, and thioamido groups, wherein the acyl, C1-20 alkyl or C5-20 aryl group is optionally substituted with one or more substituent groups selected from C1-20 alkyl, C5-20 aryl, halo, hydroxyl, ether, nitro, cyano, acyl, carboxy, ester, amido, amino, acylamido, ureido, acyloxy, thiol, thioether, sulfoxide, sulfonyl, thioamido, sulfonamido and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur.

5. The method of claim 1, wherein the compound of formula (Ib) or an isomer or salt thereof, or a mixture of any thereof, is a compound of formula (II):



or an isomer or salt thereof, or a mixture of any thereof, wherein:
RC3 is selected from C1-7 alkyl, C5-20 aryl, and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur, wherein the C1-7 alkyl, C5-20 aryl or heterocyclyl group is optionally substituted with one or more substituent groups selected from C1-20 alkyl, C5-20 aryl, halo, hydroxyl, ether, nitro, cyano, acyl, carboxy, ester, amido, amino, acylamido, ureido, acyloxy, thiol, thioether, sulfoxide, sulfonyl, thioamido, sulfonamido and a heterocyclyl group having from 3 to 7 ring atoms, of which from 1 to 4 are selected from nitrogen, oxygen and sulfur.

6. The method of claim 1, wherein the compound of formula (Ib) or an isomer or salt thereof, or a mixture of any thereof, is a compound of formula (III):



or an isomer or salt thereof, or a mixture of any thereof, wherein R is selected from:

7. The method of claim 1, wherein the compound of formula (Ib) or an isomer or salt thereof, or a mixture of any thereof, is a compound of formula (IV),



or an isomer or salt thereof, or a mixture of any thereof.

8. The method of claim 1, further comprising identifying the subject as having a cancer condition that is deficient in a HR dependent DNA DSB repair pathway.

9. The method of claim 1, further comprising administering ionizing radiation, a chemotherapeutic agent, or a combination thereof to the subject.

10. The method of claim 1, wherein the one or more cancer cells has a BRCA1 or BRCA2 deficient phenotype.

11. The method of claim 10, wherein the one or more cancer cells are deficient in BRCA1 or BRCA2.

12. The method of claim 1, wherein the subject is heterozygous for a mutation in a gene encoding a component of the HR dependent DNA DSB repair pathway.