WO2008068170A1

WO2008068170A1 - Hdac inhibitors

Info

Publication number: WO2008068170A1
Application number: PCT/EP2007/062914
Authority: WO
Inventors: William Paul Jackson
Original assignee: William Paul Jackson
Priority date: 2006-12-04
Filing date: 2007-11-27
Publication date: 2008-06-12
Also published as: GB0624187D0

Abstract

The use of compounds of the formula (I): Ar1-L1-Ar2-L2-C(R3)(R4)N(OR1)C(=Y)-R2 where Y is selected from O or S; R1 is H, a salt or readily hydrolysable substituent; R2 is selected from H or CH3, CH2F, CF2H or CF3; R3 and R4 are selected independently from H, C1-4 alkyl or alkenyl, CF3, CH2F, CF2H and F, with the proviso that if either R3 or R4 is H, then the other is not H; L1 is a linker group; L2 is a linker group comprising an optionally substituted or unsubstituted unsaturated branched or straight chain alkyl group; Ar1 is an optionally substituted or unsubstituted aryl or heterocyclic group; and Ar2 is an optionally substituted or unsubstituted aryl or heterocyclic group, in the treatment of HDAC mediated diseases or diseases provide improved therapies due to the potent inhibition of HDAC and long duration of activity in vivo after oral administration. They are potential useful in diseases in which HDAC has been implicated, e.g. psoriasis, cancer, Alzheimer's disease, Huntington's disease and HIV.

Description

HDAC Inhibitors

FIELD OF THE INVENTION

This invention pertains generally to the field of biologically active compounds, and more specifically to the use of certain hydroxamic acid compounds for the inhibition of HDAC (histone deacetylase), both in vitro and in vivo, and for the prophylaxis or treatment of HDAC implicated indications, e.g. proliferative conditions such as cancer as well as Alzheimer' s disease, Huntington's disease, HIV and psoriasis. The present invention also pertains to certain novel classes of sulphonamide-containing hydroxamic acid compounds.

BACKGROUND OF THE INVENTION

Histone deacetylases (HDACs) have been implicated in the mechanism of action of some diseases and, in particular, has been demonstrated as a potential target in proliferative diseases.

DNA in eukaryotic cells is tightly complexed with proteins (histones) to form chromatin. Histones are small, positively charged proteins which are rich in basic amino acids (positively charged at physiological pH), which contact the phosphate groups (negatively charged at physiological pH) of DNA. There are five main classes of histones, Hl, H2A, H2B, H3, and H4. The amino acid sequences of histones H2A, H2B, H3, and H4 show remarkable conservation between species, whereas Hl varies somewhat, and in some cases is replaced by another histone, e.g., H5. Four pairs of each of H2A, H2B, H3, and H4 together form a disk-shaped octomeric protein core, around which DNA (about 140 base pairs) is wound to form a nucleosome. Individual nucleosomes are connected by short stretches of linker DNA associated with another histone molecule (e.g., Hl, or in certain cases, H5) to form a structure resembling a beaded string, which is itself arranged in a helical stack, known as a solenoid.

The majority of histones are synthesised during the S phase of the cell cycle, and newly synthesised histones quickly enter the nucleus to become associated with DNA. Within minutes of its synthesis, new DNA becomes associated with histones in nucleosomal structures.

A small fraction of histones, more specifically, the amino side chains thereof, are enzymatically modified by post-translational addition of methyl, acetyl, or phosphate groups, neutralising the positive charge of the side chain, or converting it to a negative charge. For example, lysine and arginine groups may be methylated, lysine groups may be acetylated, and serine groups may be phosphorylated. For lysine, the — (CH₂)₄ -NH₂ sidechain may be acetylated, for example by an acetyltransferase enzyme, to give the amide — (CH₂)₄ — NHC(=0)CH₃. Methylation, acetylation, and phosphorylation of amino termini of histones which extend from the nucleosomal core affects chromatin structure and gene expression. (See, for example, Spencer and Davie, Gene, 1999, 240, 1-12).

Acetylation and deacetylation of histones is associated with transcriptional events leading to cell proliferation and/or differentiation. Regulation of the function of transcription factors is also mediated through acetylation. Recent reviews of histone deacetylation include Kouzarides, Curr. Opin. Genet. Dev., 9, 40-48, 1999 and Pazin et al., Cell, 89, 325-328,1997.

The correlation between the acetylation status of histones and the transcription of genes has been known for over 30 years (see, for example, Howe et al., Crit. Rev, Eukaryot. Gene Expr., 9, 231-243,1999). Certain enzymes, specifically acetylases (e.g., histone acetyltransferase, HAT) and deacetylases (e.g., histone deacetylase, HDAC), which regulate the acetylation state of histones have been identified in many organisms and have been implicated in the regulation of numerous genes, confirming the link between acetylation and transcription. See, for example, Davie, Curr. Opin. Genet. Dev., 8, 173-178, 1998. In general, histone acetylation correlates with transcriptional activation, whereas histone deacetylation is associated with gene repression.

A growing number of histone deacetylases (HDACs) have been identified (see, for example, Ng and Bird, Trends Biochem. Soc, 25, 121-126, 2000). The first deacetylase, HDACl, was identified in 1996 (see, for example,

- ? - Tauton et al., Science, 272, 408-411,1996). Subsequently, two other nuclear mammalian deacetylases have been found, HDAC2 and HDAC3 (see, for example, Yang et al., Proc. Natl. Acad. ScL USA, 93, 12845-128-50,1996, and /. Biol. Chem., 272, 28001-28007, 1997, and Emiliani et al., Proc. Natl. Acad. USA, 95, 2795-2800, 1998). See also, Grozinger et al., Proc. Natl. Acad. ScL USA, 96, 4868-4873,1999; Kao et al., Genes Dev., 14, 55-66, 2000; and Van den Wyngaert et al., FEBS Lett., 478, 77-83, 2000.

Eight human HDACs have been cloned so far: HDACl (Genbank Accession No. NP004955) HDAC2 (Genbank Accession No. NP.ooms) HDAC3 (Genbank Accession No. 015739) HDAC4 (Genbank Accession No. AAD29046) HDAC5 (Genbank Accession No. NP.005₄65) HDAC6 (Genbank Accession No. NP 006035) HDAC7 (Genbank Accession No. AAF63491) HDAC8 (Genbank Accession No. AAF73428)

These eight human HDACs fall in two distinct classes: HDACs 1, 2, 3 and 8 are in class I, and HDACs 4,5,6 and 7 are in class II.

There are a number of histone deacetylases in yeast, including the following: RPD3 (Genbank Accession No. NP.0₁₄06₉) HDAl (Genbank Accession No. P53973) HOSl (Genbank Accession No. Q12214) HOS2 (Genbank Accession No. P53096) HOS3 (Genbank Accession No. Q02959). There are also numerous plant deacetylases, for example, HD2, in

Zea mays (Genbank Accession No. AF254073]).

HDACs function as part of large multiprotein complexes, which are tethered to the promoter and repress transcription. Well characterised transcriptional repressors such as Mad (Laherty et al., Cell, 89, 349-356, 1997), pRb (Brehm et al., Nature, 391, 597-601, 1998), nuclear receptors (Wong et al., EMBO J, 17, 520-534,1998) and YYl (Yang et al., /. Biol. Chem., 272, 28001- 28007, 1997) associate with HDAC complexes to exert their repressor function.

The study of inhibitors of histone deacetylases indicates that these enzymes play an important role in cell proliferation and differentiation. The inhibitor Trichostatin A (TSA) (Yoshida et al., J Biol Chem, 265, 17174-

17179,1990) causes cell cycle arrest at both Gl and G2 phases (Yoshida, Exp. Cell.Res. , 177, 122-131, 1988), reverts the transformed phenotype of different cell lines, and induces differentiation of Friend leukaemia cells and others (Yoshida et al., J Antibiot. (Tokyo), 43, 1101-1106, 1990). TSA (and SAHA) have been reported to inhibit cell growth, induce terminal differentiation, and prevent the formation of tumours in mice (Finnin et al., Nature, 401, 188-193, 1999).

Cell cycle arrest by TSA correlates with an increased expression of gelsolin (Hoshikawa et al., Exp. Cell. Res., 214, 189-197, 1994), an actin regulatory protein that is down regulated in malignant breast cancer (Mielnicki et al., Exp. Cell. Res., 249, 161-176, 1999). Similar effects on cell cycle and differentiation have been observed with a number of deacetylase inhibitors (Kim et al., Oncogene, 18, 2461-2470,1999).

Recently, certain compounds that induce differentiation have been reported to inhibit histone deacetylases. Several experimental antitumour compounds, such as trichostatin A (TSA), trapoxin, suberoylanilide hydroxamic acid (SAHA), and phenylbutyrate have been reported to act, at least in part, by inhibiting histone deacetylase (see, e.g., Yoshida et al., J Antibiot. (Tokyo), 43, 1101-1106,1990; Richon et al., Proc. Natl. Acad. ScL USA, 93, 5705-5708, 1998; Kijima et al., /. Biol. Chem., 268, 22429-22435,1993). Additionally, diallyl sulfide and related molecules (see, e.g., Lea et al., Int. J. Oncol., 2, 347- 352,1999), oxamflatin (see, e.g., Kim et al., Oncogene, 18, 2461-2470, 1999), MS-27-275, a synthetic benzamide derivative (see, e.g., Saito et al., Proc. Natl. Acad. ScL USA, 96, 4592-4597,1999; Suzuki et al., /. Med. Chem, 42, 3001-3003, 1999; note that MS-27-275 was later re-named as MS-275), butyrate derivatives (see, e.g., Lea, Int J Oncol, 2, 347-352, 1995), FR901228 (see, e.g., Nakajima et al., Exp. Cell. Res., 241, 126-133,1998), depudecin (see, e.g., Kwon et al., Proc. Natl. Acad. ScL USA, 95, 3356-3361,1998), and m-carboxycinnamic acid bishydroxamide (see, e.g., Richon et al., Proc. Natl. Acad. Sci. USA, 95, 3003- 3007, 1998) have been reported to inhibit histone deacetylases. In vitro, some of these compounds are reported to inhibit the growth of fibroblast cells by causing cell cycle arrest in the Gl and G2 phases, and can lead to the terminal differentiation and loss of transforming potential of a variety of transformed cell lines (see, e.g., Richon et al, Proc. Natl. Acad. ScL USA, 93, 5705-5708). SAHA is reported to be effective in preventing the formation of mammary tumours in rats, and lung tumours in mice (see, e.g., Desai et al., Proc. AACR, 40, abs 2396,1999). The clear involvement of HDACs in the control of cell proliferation and differentiation suggests that aberrant HDAC activity may play a role in cancer. The most direct demonstration that deacetylases contribute to cancer development comes from the analysis of different acute promyelocytic leukaemias (APL). In most APL patients, a translocation of chromosomes 15 and 17 (t(15;17)) results in the expression of a fusion protein containing the N- terminal portion of PML gene product linked to most of RAR. alpha, (retinoic acid receptor). In some cases, a different translocation (t(l l;17)) causes the fusion between the zinc finger protein PLZF and RAR.alpha.. In the absence of ligand, the wild type RAR.alpha. represses target genes by tethering HDAC repressor complexes to the promoter DNA. During normal hematopoiesis, retinoic acid

(RA) binds RAR.alpha. and displaces the repressor complex, allowing expression of genes implicated in myeloid differentiation. The RAR.alpha. fusion proteins occurring in APL patients are no longer responsive to physiological levels of RA and they interfere with the expression of the RA-inducible genes that promote myeloid differentiation. This results in a clonal expansion of promyelocytic cells and development of leukaemia. In vitro experiments have shown that TSA is capable of restoring RA-responsiveness to the fusion RAR.alpha. proteins and of allowing myeloid differentiation. These results establish a link between HDACs and oncogenesis and suggest that HDACs are potential targets for pharmaceutical intervention in APL patients. (See, for example, Kitamura et al., Br. J. Haematol., 108, 696-702, 2000).

Furthermore, different lines of evidence suggest that HDACs may be important therapeutic targets in other types of cancer. Cell lines derived from many different cancers (prostate, colorectal, breast, neuronal, hepatic) are induced to differentiate by HDAC inhibitors (Yoshida, Ann. N. Y. Acad. ScL, 886, 23-36, 1999). A number of HDAC inhibitors have been studied in animal models of cancer. They reduce tumour growth and prolong the lifespan of mice bearing different types of transplanted tumours, including melanoma, leukaemia, colon, lung and gastric carcinomas, etc. (Ueda et al.,/ Antibiot. (Tokyo), 47, 315-323, 1994; Kim et al., Oncogene, 18, 2461-2470, 1999). Psoriasis is a common chronic disfiguring skin disease which is characterised by well-demarcated, red, hardened scaly plaques: these may be limited or widespread. The prevalence rate of psoriasis is approximately 2%, i.e., 12.5 million sufferers in the triad countries (US/Europe/Japan). While the disease is rarely fatal, it clearly has serious detrimental effects upon the quality of life of the patient: this is further compounded by the lack of effective therapies. Present treatments are either ineffective, cosmetically unacceptable, or possess undesired side effects. There is therefore a large unmet clinical need for effective and safe drugs for this condition.

Psoriasis is a disease of complex etiology. Whilst there is clearly a genetic component, with a number of gene loci being involved, there are also undefined environmental triggers. Whatever the ultimate cause of psoriasis, at the cellular level, it is characterised by local T-cell mediated inflammation, by keratinocyte hyperproliferation, and by localised angiogenesis. These are all processes in which histone deacetylases have been implicated (see, e.g., Saunders et al., Cancer Res., 59,399-404,1999; Bernhard et al, FASEB J., 13, 1999-

2001,1999; Takahashi et al, /. Antibiot. (Tokyo), 49, 453-457, 1996; Kim et al , Nature Medicine, 1, 437-443, 2001). Therefore HDAC inhibitors may be of use in therapy for psoriasis. Candidate drugs may be screened, for example, using proliferation assays with T-cells and/or keratinocytes. In view of the implication of HDAC in certain diseases, there have been several attempts to find pharmaceutically acceptable HDAC inhibitors. Among these, several hydroxamic acid derivatives have been described. US 5,534,654 describes a novel class of hydroxamic acid compounds capable of cell growth and vascularisation inhibition. In particular, it discloses a sulphonamide-containing hydroxamic acid of the structure below, known as Oxamflatin, which is used extensively in biological studies.

(2£)-/V-h yd ro xy-5-{3- [(p hen yl sulf onyl) arn mo ]p hen yl }p ent-2-e n-4-y na rni de

Oxarnflatiπ

WO-A-01/18171 describes a class of HDAC inhibiting hydroxamic acid and specifically discloses a single sulphonamide linked molecule.

WO-A-011/38322 (Delorme et al) relates to compounds for the inhibition of histone deacetylase (HDAC) enzymatic activity and methods for treating cell proliferation diseases and conditions. The compounds described therein according to the general formula are all 'normal' hydroxamic acids, substituted amides and derivatives thereof. Among exemplified compounds are a number of hydroxamic acid compounds containing sulphonamide linker groups, such as the molecule below.

More recently, in US 2004/0077726A1, a series of sulphonamide linked carbamic acid compounds as HDAC inhibitors for the treatment of cancer and psoriasis have been described. Among the described compounds are ones in which the sulphonamide linkage has been "reversed", as illustrated in the molecule below which is currently undergoing clinical trials.

WO 2007/039403 (Atlanta Pharma) discloses a class of 'normal' hydroxamic acids having N-sulphonyl pyrrole functionalities, which compounds are described as being crystalline and having HDAC inhibitory activity.

Other biologically active hydroxamic acid derivatives have been described in the prior art, but not as HDAC inhibitors. For example, there are several disclosures of hydroxamic acid derivatives as 5 -lipoxygenase inhibitors. US 4,977,188 and US 4,988,733 disclose a series of 'normal' and 'reverse' hydroxamic acid derivatives as inhibitors of 5-lipoxygenase. The second of these patents refers to a series of compounds in which L is a trans-olefin and X is oxygen. However, in neither of the patents, is a sulphonamide linking group disclosed. The preferred compounds in this case have an oxygen linking the two aryl units, e.g.

WO-A-2005/061448 is concerned with methods of treating vascular diseases, and particularly with the treatment of aneurysm, using known compounds such as amiloride and oxamflatin as well as some novel sulphonamide-containing hydroxamic acid derivatives. Among the hydroxamic acid derivatives falling within the scope of the general formula disclosed are 'reversed' hydroxamic acids (i.e. -N(OH)-COR). Whilst most specified compounds were 'normal' hydroxamic acids, one specifically stated (although not exemplified) 'reverse' hydroxamic acid structure is:

Despite the activities in this area, there are no satisfactory pharmaceutical treatments that act via HDAC inhibition. There remains a need for well tolerated and more efficacious inhibitors of HDACs.

PROBLEM TO BE SOLVED BY THE INVENTION

There is therefore a continuing problem in providing effective treatments for certain proliferative diseases such as cancer and psoriasis and other indications implicating HDAC.

It is an object of this invention to provide a pharmaceutical treatment for such proliferative diseases such as cancer and psoriasis and other indications implicating HDAC.

It is a further object of the invention to provide novel compounds that provide the desired biological activity and pharmaceutical stability to enable effective treatment of proliferative diseases, e.g. antiproliferative compounds acting via HDAC inhibition.

Thus, it is a further object of the invention to provide compounds which are potent inhibitors of histone deacetylases (HDACs). Such molecules, especially in the treatment and/or prophylaxis of certain cancers, desirably have one or more of the following properties and/or effects: (a) easily gain access to and act upon tumour cells; (b) down-regulate HDAC activity; (c) inhibit the formation of HDAC complexes; (d) inhibit the interactions of HDAC complexes; (e) inhibit tumour cell proliferation; (e) promote tumour cell apoptosis; (f) inhibit tumour growth; and, (g) complement the activity of traditional chemo therapeutic agents. SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention, there is provided a compound according to Formula I for use in the inhibition of HDAC for the treatment or prophylaxis of diseases which are HDAC mediated or in which HDAC is implicated

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (I) where

Y is selected from O or S R¹ is H, a salt or readily hydrolysable substituent;

R² is selected from H or CH₃, CH₂F, CF₂H or CF₃; R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CF₃, CH₂F, CF₂H and F, with the proviso that if either R³ or R⁴ is H, then the other is not H; L¹ is a linker group;

L is a linker group comprising an optionally substituted or unsubstituted unsaturated branched or straight chain alkyl group;

Ar¹ is an optionally substituted or unsubstituted aryl or heterocyclic group; and Ar is an optionally substituted or unsubstituted aryl or heterocyclic group.

In a second aspect of the invention, there is provided a compound of the formula (II)

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (II) where

Y is selected from O or S;

R¹ is H, a salt or readily hydrolysable substituent; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃; R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CH₂F, CF₂H, CF₃ and F, with the proviso that both R³ and R⁴ are not H; L¹ is NHSO₂, SO₂NH;

L² is an unsaturated C2-6 optionally substituted or unsubstituted branched or straight chain alkyl group;

Ar¹ is an optionally substituted or unsubstituted aryl or heterocyclic group; and

AArr²² : is an optionally substituted or unsubstituted aryl or heterocyclic group.

In a third aspect of the invention, there is provided a compound according to Formula II above for use in therapy.

In a fourth aspect of the invention, there is provided a compound according to Formula II above for use in the treatment or prophylaxis of cancer or psoriasis.

In a fifth aspect of the invention, there is provided a compound according to Formula II or Formula I above for use in the inhibition of HDAC in therapy.

In a sixth aspect of the invention, there is provided a compound according to Formula II above for use in the treatment of HDAC mediated diseases or diseases implicating HDAC by inhibition of HDAC. In a seventh aspect of the invention, there is provided a pharmaceutical formulation comprising the compound according to Formula II above and a pharmaceutically acceptable excipient.

In an eighth aspect of the invention, there is provided a use of a compound according to Formula I or Formula II above in the manufacture of a medicament for the treatment or prophylaxis of a disease in which HDAC is implicated by inhibition of HDAC.

In a ninth aspect of the invention, there is provided a method for the treatment of the human or animal body, said method comprising the step of administering to a patient exhibiting symptoms of a disease in which HDAC is implicated a therapeutically effective amount of a compound according to Formula I or Formula II above. ADVANTAGES OF THE INVENTION

The invention provides compounds for use in medical treatment by inhibition of HDAC, which compounds are inhibitors of HDAC whilst having excellent pharmaceutical stability. The invention further provides novel compounds having good biological profile and potent HDAC inhibitory activity. It is believed that by providing compounds with HDAC inhibitory activity and a long duration of activity in vivo, there is provided improved HDAC inhibitors without unacceptable toxicity. The compounds defined herein provide improved treatments of HDAC implicated indications, especially certain forms of cancer, such as non small cell lung cancer, and psoriasis, Alzheimers, Huntington's and HIV.

DETAILED DESCRIPTION OF THE INVENTION

The classes of compounds used according to the invention and the novel class of compounds defined herein are 'reverse' hydroxamic acid derivatives which are defined below. By 'reverse' hydroxamic acids, it is meant that the hydroxamic acid derivative function -N(OR)C(O)R' is formed from a 'simple' acid and a 'complex' hydroxy lamine whilst a 'normal' hydroxamic acid will have the formula -C(O)NR(OR') which is derived from a 'complex' acid and a 'simple' hydroxylamine. By simple acid, it is meant a low molecular weight carboxylic acid with minimal substituents, such as acetic acid, trifluoroacetic acid or formic acid. By simple hydroxylamine, it is meant a hydroxylamine with a low molecular weight and simple substituents, such as hydroxylamine with an NH or N-Io wer alkyl/cycloalkyl group. 'Complex' acids and hydroxy lamines will have more substantial and complex substituents. Accordingly, in a 'reverse' hydroxamic acid, the hydroxylamine portion will have a significantly higher molecular weight than the acid portion. In the case of sulphonamide-containing reverse hydroxamic acids, for example, the sulphonamide group will form part of the complex hydroxylamine portion of the molecule.

As mentioned above, the compounds according the first aspect of the invention are for use the inhibition of HDACs, by which it is meant one or more of the HDACs, and for use in the treatment or prophylaxis of diseases in which one or more HDAC is implicated or that are HDAC mediated, which treatment or prophylaxis should be effected by inhibition of HDAC.

Compounds according to the first aspect of the invention, as stated above may be defined according to the following formula I.

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (I) where

Y is selected from O or S R¹ is H, a salt or readily hydrolysable substituent, such as a hydroly sable ester, a -CH₂-ester group or a -CH₂-O-PO(OH)₂ group; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃;

R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CF₃, CH₂F, CF₂H and F, with the proviso that if either R³ or R⁴ is H, then the other is not H; L¹ is a linker group, which may be any suitable linker but is preferably selected from O, S, NHSO₂, SO₂NH;

L² is a linker group comprising an optionally substituted or unsubstituted unsaturated branched or straight chain alkyl group;

Ar¹ is an aryl or heterocyclic group, which may, for example, be an optionally substituted or unsubstituted phenyl or 5 or 6 membered heterocycle having 1-4 heteroatoms;

Ar² is an aryl or heterocyclic group, which may, for example, be an optionally substituted or unsubstituted phenyl or a 5 or 6 membered heterocycle having 1-4 heteroatoms and optionally either or both of Ar¹ and Ar² incorporate L¹ within its structure.

The compounds defined by formula I as set out above are now discussed in more detail, with further examples of each of the features of the compounds defined.

Any aryl-containing group may form Ar¹ and Ar², which may be bound to the adjacent linker group via a substituent group, but is preferably directly bonded via an aryl carbon or heteroatom. The groups Ar¹ and Ar² may independently be any suitable aryl group and may independently represent aromatic hydrocarbon and fused aromatic hydrocarbon ring structures, aromatic and non-aromatic heterocyclic groups, each of which may be substituted or unsubstituted. For example, Ar¹ and Ar² may independently represent an optionally substituted or unsubstituted C6-10 aryl group or an optionally substituted or unsubstituted aromatic or non-aromatic 5 to 10 membered heterocyclic group. The C6-10 aryl group may be selected from, for example, a phenyl or naphthyl group or tetrahydronaphthyl group, which may be substituted or unsubstituted. The 5 to 10 membered heterocyclic group may be an aromatic heterocyclic group, for example 5 or 6 membered ring structures comprising at least one ring heteroatom and optionally two, three or four heteroatoms, which may for example be selected from O, S and N. Examples of such heterocyclic groups include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, imidazolyl, pyrazolidinyl, pyrrolyl, oxadiazolyl, oxazyl, isoxazyl, thiadiazolyl, thiazolyl, 1,2,3-triazolyl, 1 ,2,4-triazolyl, tetrazolyl and pyrazolyl. Alternatively, the 5 to 10 membered heterocycle is non-aromatic, i.e. saturated or partially unsaturated, C5-10 carbocyclic ring having one or more, e.g. 2, 3 or 4, heteroatoms, which, for example, may be selected from O, S or N. Examples of such heterocylces include piperidinyl, piperazinyl, morpholinyl, pyrrolidinyl, tetrahydrofuranyl, imidazolidinyl, thiazolidinyl, 1,4-dioxanyl and 1,3-dioxanyl. Each of the above heterocycles may be substituted or unsubstituted.

The aryl, aromatic heterocycle and non-aromatic heterocyclic groups may optionally be substituted or unsubstituted, as mentioned above. If substituted, they may be substituted with any suitable substituents, which may be selected from, for example, Cl-IO alkyl, C2-10 alkenyl, C2-10 alkynyl, Cl-IO alkoxy, Cl-IO thioalkoxy, hydroxyl, Cl-IO hydroxyalkyl, halo, Cl-10 haloalkyl, amino, Cl-10 alkylamino, di(Cl-10 alkyl)amino, amido, nitro, cyano, (Cl-10 alkyl)carbonyloxy, (Cl-10 alkoxy)carbonyl, (Cl-10 alkyl)carbonyl, (Cl-10 alkyl)thiocarbonyl, (Cl-10 alkyl)sulfonylamino, aminosulfonyl, (Cl-10 alkyl)sulfinyl, (Cl-10 alkyl) sulfonyl or Cl-10 alkyl substituted by amino, Cl-10 alkoxy, Cl-10 alkylamino or di(Cl-10 alkyl)amino. Preferably the substituents may independently be selected from Cl-4 alkyl, Cl-4 alkoxy, amino, Cl-4 alkylamino, di(Cl-4 alkyl)amino), halo, Cl-4alkyl substituted by one, two or three chlorine or fluorine atoms, (Cl-4 alkoxy)carbonyl or Cl-4 alkyl substituted by amino, Cl-2 alkoxy, Cl-2 alkylamino, di(Cl-2 alkyl)amino, cyano, amido or nitro. Still more preferably the substituents may be selected from methyl, ethyl, methoxy, ethoxy, dimethylamino, bromo, chloro, fluoro, trifluoromethyl, difluoromethyl, fluoromethyl, methoxymethyl, ethoxymethyl, aminomethyl, methylaminomethyl or dimethylaminomethyl. Preferably, at least Ar² and more preferably both Ar¹ and Ar² are selected from aromatic aryl or heterocyclic systems. More preferably Ar¹ and Ar² independently represent: i) napthyl, tetrahydronapthyl, thienyl or pyridyl, any of which is optionally unsubstituted or substituted by one or more of the substituents identified above; or ii) phenyl optionally unsubstituted or substituted by one or more (e.g. two, three or four) of the substituents identified above.

More preferably, at least Ar² and still more preferably both Ar¹ and

Ar² are phenyl groups which independently are optionally unsubstituted or substituted as defined above, but preferably with one or more bromo, chloro or fluoro substituent.

Where Ar² comprises a phenyl ring, it may be linked to L¹ and L² by any two atoms but preferably meta (1,3 arrangement) or para (1,4 arrangement). Where Ar¹ comprises a substituted phenyl ring, the substitution arrangement is such that at least one substituent is meta (1,3) or para (1,4) to the bond with L¹.

L¹ is a linker group. The linker group may be any suitable group for linking Ar¹ to Ar² and for example may be selected from a single bond, -

C(R⁵)=N-, -N=C(R⁵)-, C(R⁵)(R⁶)-NR⁷-, -NR⁷-C(R⁵)(R⁶)-, -CO-NR⁵-, NR⁵-CO-, - SO₂-NR⁵-, -NR⁵-SO₂-, -C(R⁵)(R⁶)-O-, -O-C(R⁵)(R⁶)-, -C(R⁵)(R⁶)-S-, -S- C(R⁵XR⁶)-, -CONH-, NHCO-, -CO-, -SO-, -SO₂-, O, S, -[C(R⁵)R⁶]_P- (especially - CH₂-), -NH-SO₂- or -SO₂NH-, wherein R⁵, R⁶ and R⁷ each independently represents hydrogen, Cl-6 alkyl, C6-10 aryl or a 5 to 10 membered heterocyclic group and p is an integer of from 1 to 4. Preferably, L¹ is selected from O, S, NHSO₂ or SO₂NH or sulfonamide derivative. More preferably, L¹ is a sulfonamide or derivative. Optionally the -NH group of the sulfonamide forms a part of an adjacent aryl group Ar¹ or Ar². For example, the -NH group may form part of the ring structure of a pyrrole or other nitrogen containing heterocycle and form part of the linker group L¹ by being directly bound to an SO₂ group. L² is an optionally substituted or unsubstituted unsaturated branched or straight chain alkyl group and comprises one or more alkene and/or alkyne moieties. The straight chain preferably comprises C2-C6, more preferably C2-C4 and most preferably is a C2 group. Preferably, L is an ethenyl or ethynyl group. Most preferably, L² is an (E) -CH=CH- group.

One preferred class of compounds is that according to formula I in which Ar¹ is phenyl optionally substituted by one or more substituents independently selected from C 1-4 alkyl (which may be substituted by one or more halogen atoms) and halogen; Ar² is a 1,3 or 1,4 phenylene group; L¹ is O; L² is an ethenyl group, preferably the trans (E) stereoisomer; R¹ is H; R² is H or Cl-4 alkyl; R³ is H or Cl-4 alkyl; and R⁴ is Cl-4 alkyl. Preferably, the compounds of this class are in high purity enantiomeric form, preferably the S enantiomer. A particularly preferred member of this class of compounds is (E) N{ l(S)-methyl-3- [3-(4-fluorophenoxy)phenyl]prop-2-en-l-yl} acetohydroxamic acid (as disclosed in EP-A-0351214).

A more preferred class of compounds according the first aspect of the invention is a class of novel compounds described and claimed herein in accordance with a second aspect of the invention, which compounds are defined according to the formula II:

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (II) where

Y is selected from O or S;

R¹ is H, a salt or readily hydrolysable substituent, such as a hydrolysable ester, a -CH₂-ester group or a -CH₂-O-PO(OH)₂ group; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃; R³ and R⁴ are selected independently from H, Cl-4 alkyl or alkenyl, CH₂F, CF₂H, CF₃ and F, with the proviso that both R³ and R⁴ are not H;

L¹ is NHSO₂ or SO₂NH; L² is an unsaturated C2-6, preferably C2-4, optionally substituted or unsubstituted branched or straight chain alkyl group; Ar¹ is an aryl or heterocyclic group, which may, for example, be an optionally substituted or unsubstituted phenyl or 5 or 6 membered heterocycle having 1-4 heteroatoms;

Ar is an aryl or heterocyclic group, which may, for example, be an optionally substituted or unsubstituted phenyl or a 5 or 6 membered heterocycle having 1-4 heteroatoms and optionally either or both of Ar¹ and Ar² incorporate L¹ within its structure.

Ar¹ and Ar² may be any group as defined for Ar¹ and Ar² for formula I above and the preferred groups. They may each independently be optionally substituted phenyl groups or heterocycle groups, e.g. Ar² may be a thienyl, pyrrolyl or furyl group whilst Ar¹ may be a pyridyl group.

L² is preferably a C2 alkenyl or alkynyl group, more preferably ethenyl and still more preferably trans (E) ethenyl.

C(R³XR⁴) is preferably a -CH(CH₃) group. R¹ which may be H, a salt or readily hydroly sable substituent, such as a hydrolysable ester, a -CH₂-ester group or a -CH₂-O-PO(OH)₂ group, is preferably H.

Y is preferably O. R² is preferably CH₃. The compounds according to this aspect of the invention are novel and have the benefit of potent inhibition of HDAC and, at the same time, have a long duration of activity in vivo after oral administration.

In a preferred embodiment of this aspect of the invention are compounds according to the formula III

Ph¹-L¹-Ph²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (III) where

Y is selected from O or S;

R¹ is H, a salt or readily hydrolysable substituent, such as a hydrolysable ester, a -CH₂-ester group or a -CH₂-O-PO(OH)₂ group; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃; R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CH₂F, CF₂H, CF₃ and F, with the proviso that both R³ and R⁴ are not H;

L¹ is NHSO₂ or SO₂NH;

L² is an unsaturated C2-4 optionally substituted or unsubstituted branched or straight chain alkyl group;

Ph¹ is an optionally substituted or unsubstituted phenyl group

Ph² is an optionally substituted or unsubstituted phenyl group

When substituted, the phenyl groups Ph¹ and Ph² may be substituted with any of the substituents mentioned with respect to Ar¹ and Ar² above, but are preferably substituted with halides, e.g. one or more of each of F, Cl, Br or I, but preferably one or more of Br, Cl and/or F. The substitution arrangement of Ph¹ (where there is at least one substituent) is that at least one substituent relative to the bond to L¹ is in a 1,3 or 1,4 phenyl substitution pattern, but preferably 1,4. The substitution arrangement of Ph² of L² relative to L¹ is preferably 1,3 or 1,4, but more preferably 1,3. Ph² may be substituted or unsubstituted (aside from the linking groups L¹ and L²), but is preferably unsubstituted.

The following structures are particularly preferred compounds according to this aspect of the invention.

Λ/-P-(3-{[(4-fluorophenyl)sulfonyl]amιno}phenyl)-1-rnethylprop-2-yn-1-yl]-Λ/-hydroxyacetarnιde H

/V-[3-(3-{[(4-chlorophenyl)sulfonyl]aιnιno}phenyl)-1 -methylprop-2-yn-1-yl]-W-hydroxyacetaιnιde

A/-[(2£)-3-(3-{[(4-fluorophθnyl)sulfonyl]arnιno}phθnyl)-1-rnθthylprop-2-θn-1-yl]-A/-hydroxyacetarnιdθ

/V-[(2£)-3-(3-{[(4-chlorophenyl)sulfonyl]amιno}phenyl)-1 -methylprop-2-en-1-yl]-/V-hydroxyacetarnιde

/V-[3-(4-{[(4-fluorophenyl)sulfonyl]arnιno}phenyl)-1 -rnethylprop-2-yn-1-yl]-/V-hydroxyacetamιde

A/-p-(4-{[(4-chlorophenyl)sulfonyl]amino}phenyl)-1-rnethylprop-2-yn-1-yl]-A/-hydroxyacetarnide

/V-[(2£)-3-(4-{[(4-fluorophenyl)sulfonyl]arnιno}phenyl)-1-rnethylprop-2-en-1-yl]-/V-hydroxyacetarrιide

/V-[(2£)-3-(4-{[(4-fluorophenyl)sulfonyl]arnino}phenyl)-1-rnethylprop-2-en-1-yl]-/V-hydroxyacetamide

/V-[3-(4-{[(4-fluorophenyl)sulfonyl]amιno}phenyl)-1 -methylprop-2-yn-1 -yl]-/V-hydroxyethanethιoarnιde

/V-|3-(4-{[(4-chlorophenyl)sulfonyl]amιno}phenyl)-1-rnethylprop-2-yn-1-yl]-/V-hydroxyethanethιoamιde

Λ/-[(2£)-3-(4-{[(4-fluorophenyl)sulfonyl]arnιno}phenyl)-1-rnethylprop-2-en-1-yl]-Λ/-hydroxyethanethιoarnιde

- 99 -

/V-(3-{4-[(4-fluorophenyl)sulfarnoyl]phenyl)-1-methylprop-2-yn-1-yl)-/V-hycJroxyacetarnιde

/V-(3-{4-[(4-chlorophenyl)sulfarnoyl]phenyl}-1 -rnethylprop-2-yn-1-yl)-/V-hydroxyacetarnιde

/V-[(2E)-3-{4-[(4-fluorophenyl)sulfamoyl]phenyl)-1-methylprop-2-en-1-yl]-/V-hydroxyacetainide

/V-[(2£)-3-{4-[(4-fluorophenyl)sulfarnoyl]phenyl)-1-rnethylprop-2-en-1-yl]-/V-hydroxyacetarrιide

/V-(3-{3-[(4-fluorophenyl)sulfamoyl]phenyl}-1 -rnethylprop-2-yn-1-yl)-/V-hydroxyethanethιoarnιde

A/-(3-{3-[(4-chlorophθnyl)sulfarnoyl]phenyl)-1-rnθthylprop-2-yn-1 -yl)-Ai-hydroxyθthanθthιoaniιde

/V-[(2£)-3-{3-[(4-fluorophenyl)sulfarnoyl]phenyl)-1-methylprop-2-en-1 -yl]-/V-hydroxyethanethioamide

Λ/-[(2£)-3-{3-[(4-chlorophenyl)sulfamoyl]phenyl}-1-rnethylprop-2-en-1-yl]-Λ/-hydroxyethanethιoarnιde A/-[(2£)-3-{3-[(4-chlorophenyl)sulfamoyl]phenyl}-1-rnethylprop-2-en-1-yl]-A/-hydroxyacetamιde The compounds may be in the racemic form or, more preferably, in the (R) or (S) optically active forms.

/V- (3-{4-[(4-f luorop hen yl)sulfarnoyl]p hen y I }— 1 - methyl pro p-2-yn-1-yl)- /V- hydroxyethanethioa mid e

/V-(3-{4-[(4-chlorophenyl)sulfamoyl]phenyl}-1 -methylprop-2-yn-1-yl)-/V-hydroxyethanethιoamιde

/V- [(2 £)-3-{4-[(4-f luorop he nyl)sulfa mo yl]p he nyl)-1- methyl prop- 2- en- 1-yl]- /V- hydroxyethanethioa mi de

/V- [(2 £)-3-{4-[(4-f luorop he nyl)sulfa mo yl]p he nyl)-1- methyl prop- 2- en- 1-yl]- /V- hydroxyethanethioa mi de In the above general formulae, the R¹ group is defined as being a hydrogen, in order to form an N-OH group, or a derivative, bio-precursor or prodrug thereof. The R¹ group may therefore be a metal ion such as Ca⁺ or Na⁺ (or other suitable counter-ion) in order to form a salt of the N-O^" group. Alternatively, the R¹ group may be any suitable pro-drug or protective group which may be readily cleaved in vivo, e.g. by hydrolysis. Suitable such groups may be provided when R¹ represents, for example, a -CH₂-ester group or a -CH₂- 0-PO(OH)₂ or when R¹ represents the acid portion of an ester group with the O of -N-OH. Such bio-precursors or pro-drugs may further be such as to comprise any suitable substituent as the R¹ group which can be converted in vivo to the free compound or physiologically acceptable salt thereof.

The compounds described above may also be used as pharmaceutically acceptable salts thereof. A pharmaceutically acceptable salt, as referred to herein, is a salt with a pharmaceutically acceptable acid or base. Pharmaceutically acceptable acids include both inorganic acids such as hydrochloric, sulphuric, phosphoric, diphosphoric, hydrobromic or nitric acid and organic acids such as citric, fumaric, maleic, malic, acorbic, succinic, tartaric, benzoic, acetic, methanesulphonic, ethanesulphonic, benzenesulphonic or p- toluenesulphonic acid. Pharmaceutically acceptable bases include alkali metal (e.g. sodium or potassium), alkali earth metal (e.g. calcium or magnesium), zinc and iron hydroxides and organic bases such as Cl-6 alkyl amines, aralkyl amines or heterocyclic amines. An example of a primary amine salt can be the cyclohexylammonium salt, a suitable secondary amine salt may be the piperidine salt and a tertiary amine salt may be the triethylamine salt. The compounds of the invention may contain one or more chiral centre, although in the preferred embodiment of the invention it contains a single chiral centre. For the avoidance of doubt, the chemical structures depicted here are intended to embrace all stereoisomers of the compounds shown, including racemic and non-racemic mixtures and pure enantiomers and/or diastereomers. The compounds of the invention and used in accordance with the invention may be in racemic form or, preferably, in optically active form. For example, in the preferred embodiment according to formula II in which the compounds have a single chiral centre, the compounds used may include an R enantiomer in substantially pure form, an S enantiomer in substantially pure form or enantiomeric mixtures which contain an excess of the R enantiomer or an excess of the S enantiomer. Preferably, the compound has a chiral centre at the alpha position to the hydroxylamine moiety, which is in enantiomerically high purity and is preferably the S enantiomer.

The compounds of formula II and III may be prepared by, or in adapted form, procedures known and previously described in the literature. A compound of formula II or III may be prepared, for example (in a non limiting sequence) according to Scheme I below or the methods described in the examples.

Either racernic or chiral

Scheme 1 The olefinic compounds may be prepared by substituting the appropriate olefin, e.g. butenol. The thiohydroxamic acids may be prepared from the hydroxylamine using methods outlined in Synthesis, 1971, 110-130 and Heteroatom Chemistry, 13, 2002, 169-194. The broader class of compounds of formula I may be prepared by known methods, such as that above and those set out in EP-A-0299761 and EP-A- 0351214. In a further aspect of the invention, there is provided a process for the manufacture of a compound according to formula II, said process being derived from the above exemplified method. In accordance with a further aspect of the invention, there is provided a compound as defined in formula II above for use in therapy and/or diagnosis.

In accordance with a further aspect of the invention, the compounds defined above are for use in the treatment and/or prophylaxis of HDAC-mediated diseases or diseases and disorders in which HDAC is implicated. The treatment or prophylaxis is effected by administering to a patient in need thereof a therapeutically effective amount of any one of the compounds defined above. The condition and/or symptoms associated with the condition can thereby be improved. The compounds of the invention may be effective inhibitors of class I, II or III HDACs, but preferably are effective by inhibition of class I and/or class II HDACs.

HDAC mediated diseases that may be treated according to the present invention include, for example, cancer, such as breast cancer, colon cancer, colorectal cancer, esophageal cancer, glioma, leukemia, lung cancer including non-small cell lung cancer, prostate cancer, thoracic cancer, melanoma, ovarian cancer, cervical cancer, testicular cancer and renal cancer; cardiac hypertrophy; and hematological disorders such as hameoglobinopathies, thalessemia and sickle cell anemia. Further particular HDAC implicated conditions include Rubinstein-Taybi syndrome, acute promyelocytic leukaemia, acute myelogenous leukaemia and non-hodgekins lymphoma. The HDAC inhibitors of the invention may further be used for treating lupus erythematosus, stimulating hematopoietic cells, ameliorating protozoal parasitic infection, accelerating wound healing and protecting hair follicles. Other HDAC mediated disorders which may be treated according to the present invention include Alzheimer's disease, Huntington's disease, HIV infections and psoriasis and related disorders. Preferably, the compounds of the present invention may be used in the treatment of HDAC mediated or implicated proliferative disorders. In particular, it may be used in treatment of cancer by targeting cancer cell proliferation (e.g. by repression of certain cyclin dependent kinases). The compounds of the invention may, in some circumstances, be advantageously used in combination with other therapies and in particular with other drug therapies. Optionally the compounds described herein can be coadministered together with or sequentially with a second drug. The combination therapy resulting may have a synergistic benefit. For example, in the treatment of cancer, the compounds described herein may optionally be co-administered with, for example, platinum drugs such as cis-platin, alkylating agents such as chlorambucil or temozolomide, topoisomerase inhibitors such as the Topo II inhibitor etoposide, kinase cdk inhibitors such as flavopiridol or roscovitine, bcr-abl kinase inhibitors such as Glivec (RTM), hsp 90 inhibitors, telomerase inhibitors and/or carbamylating agents. Other chemotherapeutic or antineoplastic agents that may be coadministered with compounds described herein include, for example, mitoxantron, Vinca alkaloids such as vincristine and vinblastine, anthracycline antibiotics, taxanes such as paclitaxel, antifolates such as methotrexate and camptothecins such as irinotecan.

Preferably, in order to efficiently target proliferative cancer cells via apoptosis the compounds of the invention may be co-administered with a topoisomerase II inhibitor such as etoposide or with roscovotine.

The compounds described herein may be co-administered with other HDAC inhibitors, for example TSA or SAHA. The compounds described herein may be co-administered with other psoriasis therapies such as, for example, biologies such as TNF alpha inhibitors Remicade (RTM) and Enbrel, systemic therapies such as cyclosporine and topical applications such as Dovonex (RTM) or topical steroids. For medical use, the amount required of a compound defined above

(hereinafter referred to as the active ingredient) to achieve a therapeutic effect will very much depend upon the particular compound used, the route of administration and with the particular disorder or disease being treated or prevented. Nevertheless, a suitable dose of a compound of formula (I) or (II) or a physiologically acceptable salt or derivative thereof for a mammal suffering from or at risk of suffering from any condition as described herein before (i.e. mediated by or implicating HDAC) is in the range 0.1 μg to 500 mg of the compound per kg of bodyweight. In the case of systemic administration, a suitable dose may be 0.5 mg to 500 mg per kg bodyweight, preferably 0.5 mg to 50 mg, for example from 5 mg to 25 mg per kg, administered, for example, three times daily. In the case of topical administration, a suitable dose is in the range of 0.1 ng to 100 μg per kg bodyweight, typically about 0.1 μg/kg.

In the case of oral dosing, a preferred dosage may be, for example, 1 mg to lOmg of compound per kg bodyweight, more preferably lmg to 5mg per kg, for example 1 mg to 2 mg per kg.

Whilst it may be possible for the compounds defined above to be administered alone, it is preferable to present it as a pharmaceutical formulation, which is provided as a further aspect of the present invention, and which comprises a compound of the formula I or formula II or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient. Typically, the active ingredient comprises from 0.1 to 99.9% by weight of the formulation. Unit doses may comprise from 0.1 mg to 1 g of the active ingredient. For topical administration, the active ingredient preferably constitutes from 1% to 2% by weight of the formulation, but may constituted as much as 10% w/w. Formulations suitable for nasal or buccal administration typically comprise from 0.1 to 20% w/w, for example 2% w/w of active ingredient. The pharmaceutical acceptable carrier or excipient should be compatible with other ingredients of the formulation and not detrimental to the recipient.

Formulations according to the invention include those in a form suitable for oral, pulmonary, ophthalmic, rectal parenteral (including subcutaneous, intramuscular and intravenous), intra-articular, topical, nasal or buccal administration. Formulations suitable for oral administration may be in the form of discrete units such as capsules, tablets or lozenges, each containing a predetermined amount of active ingredient; in the form of a powder or granules; in the form of a solution or suspension in an aqueous or non-aqueous liquid; or in the form of an oil-in-water or water-in-oil emulsion. Formulations for rectal administration may be in the form of a suppository incorporating the active ingredient, or in the form of an enema. Formulations for parenteral administration typically comprise a sterile aqueous preparation of the active ingredient, which is preferably isotonic with the blood of the recipient. Formulations for intra- articular administration may be in the form of a sterile aqueous preparation of the active ingredient, which may be in microcrystalline form. Formulations suitable for topical administration include liquid and semi liquid preparations such as liniments, lotions and applications; oil-in-water and water-in-oil emulsions such as creams, ointments and pastes; and solutions and suspensions such as drops.

In addition to the aforementioned ingredients, the formulations of the invention may include one or more additional ingredients such as diluents, buffers, flavouring agents, binders, surface active agents, thickeners, lubricants, preservatives, emulsifying agents and the like. According to a further aspect, the invention provides the use of the above defined compounds in the manufacture of a medicament for the treatment or prophylaxis of a disease in which HDAC is implicated by inhibition of HDAC. The disease in which HDAC is implicated may be, for example selected from the HDAC implicated diseases mentioned above, but is preferably is selected from cancer and psoriasis. Where the disease is cancer, this may be, for example, one or more of breast cancer, colon cancer, colorectal cancer, esophageal cancer, glioma, lung cancer including non-small cell lung cancer, prostate cancer, thoracic cancer, ovarian cancer, cervical cancer, testicular cancer, renal cancer, Rubinstein- Taybi syndrome, acute promyelocytic leukaemia, acute myelogenous leukaemia and non-Hodgekins lymphoma. There is further provided a use of a compound as defined in Formulae I and II above and/or a second anti-cancer drug in the manufacture of a medicament comprising the compound of Formulae I or II and said second anti-cancer drug for the treatment of cancer by a combination or dual mechanism therapy, said second anti -cancer drug being preferably selected from for example, platinum drugs such as cis-platin, alkylating agents such as chlorambucil or temozolomide, topoisomerase inhibitors such as the Topo II inhibitor etoposide, kinase cdk inhibitors such as flavopiridol or roscovitine, bcr- abl kinase inhibitors such as Glivec (RTM), hsp 90 inhibitors, telomerase inhibitors and/or carbamylating agents, mitoxantron, Vinca alkaloids such as vincristine and vinblastine, anthracycline antibiotics, taxanes such as paclitaxel, antifolates such as methotrexate and camptothecins such as irinotecan.

Compounds described herein, and preferred compounds, especially those of formula II above, are particularly effective in the treatment of HDAC mediated diseases, it is believed, and without being bound by theory, because the 'reverse' hydroxamic acid classes described herein surprisingly have very good HDAC inhibitory activity, surprisingly well retained over the 'normal' hydroxamic acid HDAC inhibitors, whilst having improved duration of action in vivo as a result of reduced metabolism by 'reversing' the hydroxamic acid moiety. Furthermore, the alpha-methylene substituent provides improved duration of action, whilst the preferred linker groups and their arrangement provide surprisingly improved activity and duration of action.

The invention will now be described in more detail, without limitation, with reference to the Examples.

EXAMPLES The following examples are provided as an illustration of the preparation of the compounds of the invention and are non-limiting. Example 1

4-Iodoaniline (Hg) was dissolved in dichloroethane (150ml). Triethylamine (20ml) was added and the mixture cooled to 0-5 ⁰C. A- Chlorobenzensulphonyl chloride (16g) was added in potions over Ih. After a further Ih, the mixture was washed with dilute hydrochloric acid, the DCE layer separated and dried. After removal of the solvent and treating the residue with isopropyl ether, 16.5g coupled product was obtained.

The iodide (7.9g) was mixed with butyn-2-ol (2g), copper (I) iodide (250mg), tetra-kis-triphenyl phosphine Pd (0) (0.5g) and ethyl acetate (40ml) under nitrogen. Triethylamine (6ml) was added, during which time the solids dissolved and there was an exotherm. After Ih (complete reaction) the mixture was washed with dilute HCl and the solution was dried over magnesium sulphate. After filtration (also removes Cu salts), the solvent was removed and the crude product triturated with isopropyl ether to give the product (6.5g). The alcohol (3g) was dissolved in dichloromethane (25ml) together with bis-BOC hydroxylamine (2.65g) and triphenylphosphine (2.9g). After cooling in an ice bath, di-isopropyl azocarboxylate (2.4g) was added dropwise. After 2h, the solvent was removed and the residue treated with 10% toluene in hexane. After adding a trace of silica gel, the phosphine oxide:hydrazine complex crystallised and was then filtered. The residue was purified by chromatography (1: 1 DCM:hexane then 2:1) to give 2.3g product.

The bis-BOC product (l.lg) was dissolved in 5ml DCM and 2.5ml trifluoroacetic acid added. After 3h, the mixture was poured on to sodium bicarbonate/water. The hydroxylamine was extracted with DCM and dried. After removal of the solvent, the residue was treated with isopropyl ether to give the hydroxylamine (mpt, 155-156 ⁰C).

The hydroxylamine (650mg) was treated with 2 equivalents of acetyl chloride in pyridine (3ml) and dichloromethane (5ml). After 3h, the mixture was diluted with dichloromethane and washed with dilute HCl. After drying, the residue was dissolved in methanol (10ml) and treated with potassium carbonate (0.5g). After Ih, the solvent was removed, dilute HCl added and the residue isolated into dichloromethane. After drying and concentration to low volume, the product was filtered to afford 380mg, mpt 173-174. The 3 -acetylenes may be similarly prepared.

The compounds may also be prepared by coupling with the bis-Boc acetylene.

Example 2

The olefinic compounds may be prepared as shown below:

The iodide (4g), triethylamine (2.5ml), palladium acetate (230mg), triphenyl phosphine (0.52g) and the olefin (2.5g- prepared by a Mitsunobu reaction between the alcohol and bis-acetyl hydroxylamine) were dissolved in acetonitrile (15ml) and DMF (4ml) and warmed to reflux for 4h. The solvent was removed and replaced by toluene (20ml). After washing with dilute HCl, the toluene was removed and replaced with methanol (10ml). Sodium hydroxide (ImI, 18M) was added and the mixture stirred for Ih. The methanol was removed, water added and the aqueous washed with diethyl ether. After acidification, the aqueous layer was extracted with DCM. After drying, the solvent was removed and the residue purified by chromatography (ethyl acetate) to give 62mg product as a glass.

Example 3

The following experimental sets out a procedure, as a non-limiting illustration, for preparing 'reverse sulfonamide' (relative to Examples 1 and 2) linked (L¹) acetylene linked (L²) hydroxamic acid derivatives according to the present invention. Stage 1

3-b rorn o- U- (4-fl uoroph enyl) benzene sulfon ami de

3-Bromobenzene sulphonyl chloride (25.5g, 0.1 mole) is dissolved in dichloromethane (150ml) and sodium bicarbonate added (17g, 0.2 mole). 4- Fluoroaniline (22.6g, 0.2 mole) is added and the mixture stirred overnight. Water is added and the DCM phase separated, washed twice with 100ml 3M HCl. The solution is dried and the solvent removed to afford the crude sulphonamide in essentially quantitative yield.

Stage 2

U- (4- flu oro phe ny I) -3- (3-h yd rox yb ut-1 -y n- 1 -y I) be niene sulfon ami de

The crude stage 1 product is dissolved in DMF (250ml) and copper (I) iodide (Ig) is added. Triethylamine (21ml, 1.5eq) is added followed by 3- butyn-2-ol (11ml, 1.5eq). The mixture is warmed to 80 ⁰C under nitrogen for 0.5h then cooled to 50 ⁰C and bis(acetonitrile) palladium (II) chloride (1.3g, 5%) added. The mixture is then heated at 80 ⁰C for approximately 6h or until the bromide is consumed (tic analysis). The mixture is quenched with 1 litre water and the product extracted with 3 x 150ml toluene. The combined toluene fractions are washed with water. The solvent is removed and the product used without further purification.

Stage 3

A/- (4-flu oro ph enyl)-3-[3- (h yd ro xyarmin o) but- 1 -yn-1 -yl]ben zene sulfona mi de

The crude stage 2 product is dissolved in dichloromethane (400ml). Pyridine (16ml, 2eq) and DMAP (200mg) are added and the mixture cooled to 0 ⁰C. Methane sulphonyl chloride (10ml, 1.25eq) is added dropwise over about 0.5h and the mixture is allowed to warm to room temperature until the reaction is complete (approximately 4h). The mixture is washed with 2M HCl (2 x 200ml) and water. The solvent is removed and the crude product dissolved in NMP (200ml). Aqueous hydroxylamine solution is added (30ml, 15g, 4.5eq) and the mixture stirred for 4h. 1.5 litres of water were added and the product extracted with dichloromethane (2 x 200ml). The dichloromethane layer is washed twice with water and dried. After removal of the drying agent, the solution is used directly in the next reaction.

Stage 4

A/- (3-{3-[(4-fluorop hen yl)su lfarn oyl]phenyl}-1 -m ethylp rop-2-yn- 1 -yl)-A/-hyd ro xya cetarnι de

The solution from stage 3 is mixed with pyridine (25ml) and cooled in an ice bath. Acetyl chloride (10ml) is added dropwise over about 15 mins. The mixture is stirred at room temperature for 2h. 2M Hydrochloric acid (150ml) is added and the organic phase separated, washed with water and dried. After removal of solvent, the crude product is dissolved in 200ml methanol and treated with potassium carbonate (Ig). After 2h, the methanol is removed, the product extracted into dichloromethane (200ml) and washed with water. After drying and removal of solvent, the product is passed through a short silica column eluting with ethyl acetate/ hexane. The isloated product is crystallised from ethyl acetate/hexane. HPLC purity >99%.

The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.

Claims

CLAIMS:

1. A compound according to Formula I for use in the inhibition of HDAC for the treatment or prophylaxis of diseases which are HDAC mediated or in which HDAC is implicated

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (I) where

Y is selected from O or S R¹ is H, a salt or readily hydrolysable substituent;

2. A compound as claimed in claim 1, wherein R² is methyl.

3. A compound as claimed in claim 1 or claim 2, wherein R³ is H and R⁴ is methyl.

4. A compound as claimed in any one of claims 1 to 3, wherein L¹ is selected from CH₂O, OCH₂, CH₂, CONH, NHCO, O, S, SO₂NH and NHSO₂.

5. A compound as claimed in any one of the preceding claims, wherein Ar¹ and Ar² are optionally substituted or unsubstituted phenyl groups.

6. A compound of the formula (II)

Ar¹-L¹-Ar²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (II) where

Y is selected from O or S;

R¹ is H, a salt or readily hydrolysable substituent; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃;

R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CF₃, CH₂F, CF₂H and F, with the proviso that if either R³ or R⁴ is H, then the other is not H;

L¹ is NHSO₂, SO₂NH; L² is an unsaturated C2-6 optionally substituted or unsubstituted branched or straight chain alkyl group;

Ar² is an optionally substituted or unsubstituted aryl or heterocyclic group.

7. A compound as claimed in claim 6, wherein R² is methyl.

A compound as claimed in claim 6 or claim 7, wherein R³ is H and R⁴ is methyl.

9. A compound as claimed in claim 6, which is further defined according to the formula (III)

Ph¹-L¹-Ph²-L²-C(R³)(R⁴)N(OR¹)C(=Y)-R² (III) where Y is selected from O or S;

R¹ is H, a salt or readily hydrolysable substituent; R² is selected from H or CH₃, CH₂F, CF₂H or CF₃; R³ and R⁴ are selected independently from H, C 1-4 alkyl or alkenyl, CH₂F, CF₂H, CF₃ and F, with the proviso that both R³ and R⁴ are not H; L¹ is NHSO₂ or SO₂NH;

Ph¹ is an optionally substituted or unsubstituted phenyl group Ph is an optionally substituted or unsubstituted phenyl group

10. A compound as claimed in claim 9, wherein R is methyl.

11. A compound as claimed in claim 9 or claim 10, wherein R³ is H and R⁴ is methyl.

12. A compound as claimed in any one of claims 9 to 11, wherein Ph² has a 1,3 or 1,4 substitution arrangement with respect to L¹ and L².

13. A compound as claimed in any one of claims 9 to 12, wherein Ph¹ comprises at least one substituent which is selected from F, Cl or Br.

14. A compound as claimed in claim 13, wherein the at least one substituent of Ph¹ forms a 1,4 substitution arrangement on Ph¹ with L¹.

15. A compound as claimed in any one of claims 6 to 14, wherein L² is a trans ethylene group.

16. A compound as claimed in any one of claims 6 to 15, which is present in high purity enantiomeric form.

17. A compound as defined in claims 6 to 16 for use in therapy.

18. A compound as defined in claims 6 to 16 for use in the treatment or prophylaxis of cancer, psoriasis, Alzheimer's, Huntington's disease or HIV.

19. A compound as defined in claims 1 to 16 for use in the inhibition of HDAC in therapy.

20. A compound as defined in claims 6 to 16 for use in the treatment of HDAC mediated diseases or diseases implicating HDAC by inhibition of HDAC.

21. A pharmaceutical formulation comprising the compound as defined in any one of claims 6 to 16 and a pharmaceutically acceptable excipient.

22. A pharmaceutical formulation as claimed in claim21 for oral administration.

23. A pharmaceutical formulation as claimed in claim 21 for topical administration.

24. Use of a compound as defined in any one of claims 1 to 16 in the manufacture of a medicament for the treatment or prophylaxis of a disease in which HDAC is implicated by inhibition of HDAC.

25. A use as claimed in claim 21, wherein the disease in which HDAC is implicated is selected from cancer, psoriasis, Alzheimer's disease, Huntington's disease and HIV.

26. A use as claimed in claim 24 or claim 25 wherein the disease in which HDAC is implicated is selected from breast cancer, colon cancer, colorectal cancer, esophageal cancer, glioma, lung cancer including non-small cell lung cancer, prostate cancer, thoracic cancer, ovarian cancer, cervical cancer, testicular cancer, renal cancer, Rubinstein-Taybi syndrome, acute promyelocytic leukaemia, acute myelogenous leukaemia and non-Hodgekins lymphoma.

27. A method for the treatment of the human or animal body, said method comprising the step of administering to a patient exhibiting symptoms of a disease in which HDAC is implicated a therapeutically effective amount of a compound as defined in any one of claims 1 to 16.