WO2007062459A1 - Selective kinase inhibitors based on pyridine scaffold - Google Patents

Abstract

There is described a compound of the general formula (I) or pharmaceutically acceptable prodrugs, salts, hydrates, solvates, crystal forms, and isomeric forms thereof, a pharmaceutical composition comprising a compound of general formula (I), a method for the treatment of a tyrosine kinase-associated disease state and a method of suppressing the immune system using a compound of general formula (I).

Description

SELECTIVE KINASE INHIBITORS BASED ON A PYRIDINE SCAFFOLD

FIELD OF THE INVENTION

The present invention relates to the field of inhibitors of protein tyrosine kinases in particular the JAK family of protein tyrosine kinases.

BACKGROUND OF THE INVENTION

Protein kinases are a family of enzymes that catalyse the phosphorylation of specific residues in proteins. In general, protein kinases fall into several groups; those which preferentially phosphorylate serine and/or threonine residues, those which preferentially phosphorylate tyrosine residues and those which phosphorylate both tyrosine and Ser/Thr residues. Protein kinases are therefore key elements in signal transduction pathways responsible for transducing extracellular signals, including the action of cytokines on their receptors, to the nuclei, triggering various biological events. The many roles of protein kinases in normal cell physiology include cell cycle control and cell growth, differentiation, apoptosis, cell mobility and mitogenesis.

Protein kinases include, for example, but are not limited to, members of the Protein

Tyrosine Kinase family (PTKs), which in turn can be divided into the cytoplasmic PTKs and the receptor PTKs (RTKs). The cytoplasmic PTKS include the SRC family, (including: BLK; FGR; FYN; HCK; LCK; LYN; SRQYES and YRK); the BRK Family (including: BRK; FRK, SAD; and SRM); the CSK family (including: CSK and CTK); the BTK family, (including BTK; ITK; TEC; MKK2 and TXK), the Janus kinase family,

(including: JAKI, JAK2, JAK3 and Tyk2), the FAK family (including, FAK and PYK2); the Fes family (including FES and FER), the ZAP70 family (including ZAP70 and SYK); the ACK family (including ACKl and ACK2); and the AbI family (including ABL and ARG). The RTK family includes the EGF-Receptor family (including, EGFR, HER2, HER3 and HER4); the Insulin Receptor family (including INS-R and IGFl-R ); the PDGF-Receptor family (including PDGFRα, PDGFRβ, CSFlR, KIT, FLK2 ); the VEGF-Receptor family (including; FLTl, FLKl and FLT4); the FGF-Receptor family (including FGFRl, FGFR2, FGFR3 and FGFR4 ); the CCK4 family (including CCK4); the MET family (including MET and RON); the TRK family (including TRKA, TRKB, and TRKC ); the AXL family (including AXL, MER, and SKY); the TIE/TEK family (including TIE and TIE2/TEK); the EPH family (including EPHAl, EPHA2, EPHA3, EPHA4, EPHA5, EPHA6, EPHA7, EPHA8, EPHB 1, EPHB2, EPHB3, EPHB4, EPHB5, EPHB6); the RYK family (including RYK); the MCK family (including MCK and TYROlO); the ROS family (including ROS); the RET family (including RET); the LTK family (including LTK and ALK); the ROR family (including RORl and ROR2); The Musk family (including Musk); the LMR family including LMRl, LMR2 and LMR3); and the SuRTKlOO family (including SuRTKlOo).

Similarly, the serine /threonine specific kinases comprise a number of distinct sub-families, including; the extracellular signal regulated kinases, (p42/ERK2 and p44/ERKI); c-Jun NH2-terminal kinase (JNK); cAMP-responsive element-binding protein kinases (CREBK); cAMP-dependent kinase (CAPK); nitrogen-activated protein kinase-activated protein kinase (MAPK and its relatives); stress-activated protein kinase p38/SAPK2; nitrogen-and stress-activated kinase (MSK); protein kinases, PKA, PKB and PKC inter alia.

Additionally, the genomes of a number of pathogenic organisms possess genes encoding protein kinases. For example, the malarial parasite Plasmodium falciparum and viruses such as HPV and Hepatitis viruses appear to bear kinase related genes.

Inappropriately high protein kinase activity has been implicated in many diseases resulting from abnormal cellular function. This might arise either directly or indirectly, for example by failure of the proper control mechanisms for the kinase, related for example to mutation, over-expression or inappropriate activation of the enzyme; or by over- or under-production of cytokines or growth factors also participating in the transduction of signals upstream or downstream of the kinase. In all of these instances, selective inhibition of the action of the kinase might be expected to have a beneficial effect. Diseases where aberrant kinase activity has been implicated include: diabetes; restenosis; atherosclerosis; fibrosis of the liver and kidney; ocular diseases; myelo- and lymphoproliferative disorders; cancer such as prostate cancer, colon cancer, breast cancer, head and neck cancer, leukemia and lymphoma; and, auto-immune diseases such as Atopic Dermatitis, Asthma, rheumatoid arthritis, Crohn's disease, psoriasis, Crouzon syndrome, achondroplasia, and thanatophoric dysplasia.

The JAK family of protein tyrosine kinases (PTKs) play a central role in the cytokine dependent regulation of the proliferation and end function of several important cell types of the immune system.

A direct comparison of the four currently known mammalian JAK family members reveals the presence of seven highly conserved domains (Harpur et al, 1992). In seeking a nomenclature for the highly conserved domains characteristic of this family of PTKs, the classification used was guided by the approach of Pawson and co-workers (Sadowski et al, 1986) in their treatment of the SRC homology (SH) domains. The domains have been enumerated accordingly with most C-terminal homology domain designated JAK Homology domain 1 (JHl). The next domain N-terminal to JHl is the kinase-related domain, designated here as the JH2 domain. Each domain is then enumerated up to the JH7 located at the N-terminus. The high degree of conservation of these JAK homology (JH) domains suggests that they are each likely to play an important role in the cellular processes in which these proteins operate. However, the boundaries of the JAK homology domains are arbitrary, and may or may not define functional domains. Nonetheless, their delineation is a useful device to aid the consideration of the overall structural similarity of this class of proteins.

The feature most characteristic of the JAK family of PTKs is the possession of two kinase- related domains (JHl and JH2) (Wilks et al, 1991). The putative PTK domain of JAKl (JHl) contains highly conserved motifs typical of PTK domains, including the presence of a tyrosine residue at position 1022 located 11 residues C-terminal to sub-domain VII that is considered diagnostic of membership of the tyrosine-specific class of protein kinases

Alignment of the human JAKl PTK domain (255 amino acids), with other members of the PTK class of proteins revealed homology with other functional PTKs (for example, 28% identity with c-fes (Wilks and Kurban, 1988) and 37% homology to TRK (Kozma et al, 1988)). The JHl domains of each of the JAK family members possess an interesting idiosyncrasy within the highly conserved sub-domain VIII motif (residues 1015 to 1027 in JAK2) that is believed to lie close to the active site, and define substrate specificity. The phenylalanine and tyrosine residues flanking the conserved tryptophan in this motif are unique to the JAK family of PTKs. Aside from this element, the JHl domains of each of the members of the JAK family are typical PTK domains. Furthermore, there is high sequence identity in the JAK family particularly in and around the ATP binding site (Figure 1).

The central role played by the JAK family of protein tyrosine kinases in the cytokine dependent regulation of the proliferation and end function of several important cell types means that agents which inhibit JAK are useful in the prevention and chemotherapy of disease states dependent on these enzymes. Potent and specific inhibitors of each of the currently known four JAK family members will provide a means of inhibiting the action of those cytokines that drive immune pathologies, such as asthma and as immunosuppressive agents for, amongst others, organ transplants, lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, Alzheimer's disease, and leukemia/lymphoma.

The JAK/STAT Pathway

The delineation of a particularly elegant signal transduction pathway downstream of the non-protein tyrosine kinase cytokine receptors has recently been achieved. In this pathway the key components are: (i) A cytokine receptor chain (or chains) such as the Interleukin-4 receptor or the Interferon γ receptor; (ii) a member (or members) of the JAK family of PTKs; (iii) a member(s) of the STAT family of transcription factors, and (iv) a sequence specific DNA element to which the activated STAT will bind.

A review of the JAK/STAT literature offers strong support to the notion that this pathway is important for the recruitment and marshalling of the host immune response to environmental insults, such as viral and bacterial infection. This is well exemplified in Table 1 and Table 2. Information accumulated from gene knock-out experiments have underlined the importance of members of the JAK family to the intracellular signalling triggered by a number of important immune regulatory cytokines. The therapeutic possibilities stemming from inhibiting (or enhancing) the JAK7STAT pathway are thus largely in the sphere of immune modulation, and as such are likely to be promising drugs for the treatment of a range of pathologies in this area. In addition to the diseases listed in Tables 1 and 2, inhibitors of JAKs could be used as immunosuppresive agents for organ transplants and autoimmune diseases such as lupus, multiple sclerosis, rheumatoid arthritis, Type I diabetes, autoimmune thyroid disorders, Alzheimer's disease and other autoimmune diseases. Additionally, treatment of cancers such as prostate cancer by JAK inhibitors is indicated.

Table 1 - Activation of the JAK/STAT pathway in various pathologies

Table 2: Diseases Potentially Treatable By JAK-Based Drug Therapies

Jak 3 Signalling

Although the other members of the Jak family are expressed by essentially all tissues, JAK3 expression appears to be limited to hematopoietic cells. This is consistent with its essential role in signalling through the receptors for IL-2, IL4, IL-7, IL-9 and BL- 15 by non-covalent association of JAK3 with the gamma chain common to these multichain receptors. Males with X-linked severe combined immunodeficiency (XSCID) have defects in the common cytokine receptor gamma chain (gamma c) gene that encodes a shared, essential component of the receptors of interleukin-2 (EL-2), IL-4, IL-7, IL-9, and IL-15. An XSCID syndrome in which patients with either mutated or severely reduced levels of JAK3 protein has been identified, suggesting that immunosuppression should result from blocking signalling through the JAK3 pathway. Gene Knock out studies in mice have suggested that JAK3 not only plays a critical role in B and T lymphocyte maturation, but that JAK3 is constitutively required to maintain T cell function. Taken together with the biochemical evidence for the involvement of JAK3 in signalling events downstream of the IL-2 and IL-4 receptor, these human and mouse mutation studies suggest that modulation of immune activity through the inhibition of JAK3 could prove useful in the treatment of T- cell and B-cell proliferative disorders such as transplant rejection and autoimmune diseases.

Prolonged immunomodulation through inhibition of JAK3 signalling should have great therapeutic potential as long as JAK3 inhibition was achieved selectively and not accompanied by inhibition of other kinase-dependent signalling processes. In particular, the high degree of sequence identity held in common by members of the JAK family of kinases raises the possibility that a compound which inhibits Jak3 would also inhibit other members of the family with detrimental long term consequences. For example, prolonged inhibition of Jak2 is likely to lead to erythropenia and thrombocytopenia, since the receptors for both erythropoietin and thrombopoietin use only JAK2 for intracellular transmission of signals.

Selective and Irreversible Inhibition

A PTK catalyses the transfer of a phosphate group from a molecule of ATP to a tyrosine residue located on a protein substrate. The inhibitors known in the art are usually competitive with either the ATP or the protein substrate of the kinase (Levitzki 2000). Since the concentration of ATP in a cell is normally very high (millimolar), compounds that are competitive with ATP may lack in vivo activity since it is unlikely that said compounds can reach the concentrations within the cell that are necessary to displace the ATP from its binding site.

An alternative approach which has been attempted in relation to EGFR is to design or select compounds which bind to EGFR TK in an irreversible manner. Such compounds are disclosed in Fry 1998; Discafani 1999; Smaill 1999; Smaill 2000; Tsou 2001; Smaill 2001; Wissner 2003. These compounds function as irreversible inhibitors by virtue of the fact that they can form covalent bonds to amino acid residues located at the active site of the enzyme which results in enhanced potency of the compounds in vitro and in the inhibition of growth of human tumours in vivo models of cancer. A further benefit of such irreversible inhibitors when compared to reversible inhibitors, is that irreversible inhibitors can be used in prolonged suppression of the tyrosine kinase, limited only by the normal rate of receptor turnover.

The high homology between members of the JAK family of kinases makes the design of compounds with acceptable selectivity highly challenging. It is believed that by exploiting the minor differences in the amino acid sequence between the members of this family may allow for the identification of selective inhibitors. Alignment of the four members of the JAK family of protein tyrosine kinases reveals that within the amino acids that comprise the ATP-binding pocket of these kinases there are very few amino acid differences that could be used to target potential inhibitors towards one family member or another. Interestingly, JAK3 alone amongst this sub-family of kinases possesses a Cysteine residue close to the front lip of the ATP-binding cavity. It was hypothesised, by the present inventors, that this may provide a means to develop highly specific JAK3 inhibitors

(Figure 2), by targeting this Cysteine with a functionality bearing an alkylating group such as a Michael acceptor, or other such group that can react reversibly or irreversibly with the thiol moiety of this Cysteine residue.

SUMMARY OF THE INVENTION

The present inventors have found that a group of compounds based upon a disubstituted pyridine scaffold which may include an alkylating group such as a Michael acceptor are selective inhibitors of the enzyme Janus Kinase 3 and as such may be useful in therapy as immunosuppressive agents for organ transplants, lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, asthma, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, Alzheimer's disease, and other indications where immunosuppression would be desirable. Furthermore, it is believed that these compounds may find application in therapeutic treatments for proliferative diseases such as Leukaemia and Lymphoma where JAK3 is hyperactivated. Accordingly, in a first aspect the present invention provides a compound of the general formula I:

I

or pharmaceutically acceptable prodrugs, salts, hydrates, solvates, crystal forms, and isomeric forms selected from the group consisting of conformational isomers, enantiomeric forms, diastereomeric forms, Optical isomers, stereoisomers, tautomers and mixtures thereof, wherein:

A can be a bond, NH, O, S, S(O)_n, or can be selected from:

where * represents the point of attachment to the pyridine ring,

where n = 1 or 2;

and Rl and R2 are independently selected from H, C_1-4 alkyl, C_2-4alkyl0H,

C_2-4alkylNR3R4; B is alkyl, Cs-scycloalkyl, aryl, hetaryl, Ci_-4alkylaryl, C_1-4alkylhetaryl, cyclohetalkyl, substituted with 0-3 substituents independently selected from halogen, C_1-4alkyl, CF₃, CN, aryl, hetaryl, OH, OCF₃, OC_1-4alkyl, OC_{2- 5}alkylNR3R4, Oaryl, Ohetaryl, C0R3, CO₂R3, CONR3R4, NR3R4, C_{1- 4}alkylNR3R4, NR5C_2-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4,

NR3SO₂R4;

R3, R4 are each independently H, C_1-4alkyl, C_1-4alkylcyclohetalkyl, aryl, hetaryl, C_1-4alkylaryl, C_1-4 alkylhetaryl, or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR6;

R5 and R6 are independently selected from H, C_1-4 alkyl;

D is a bond, NH, O, C(O), S(0)_m, C_1-4alkyl, C_2-4alkenyl, alkylcycloalkyl, C_1-4alkylNR7, C_1-4alkylO, C_1-4alkylS(O)_m, where m = 0,1,2;

R7 is selected from H, C_1-4 alkyl, C_2-4alkylOH, C_2-4alkylNR3R4;

E is aryl, hetaryl, optionally substituted with 0-2 substituents independently selected from halogen, C_1-4 alkyl, CF₃, CN, OH, OCF₃, OC_1-4alkyl, OC_2-5alkylNR3R4, COR3, CO₂R3, CONR3R4, NR3R4, C_1-4alkylNR3R4, NR5C_1-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4, NR3COOR3, C_1-4alkylNR3COOR3, NR3SO₂R4; and R3, R4, R5 are as described previously;

G is H or selected from:

where # is point of attachment to E;

W is NR8, O or a bond;

p is 0-4;

R8 is selected from H, C_1-4 alkyl;

R9 and RlO are independently selected from H, C_1-4 alkyl, aryl, hetaryl, C_1-4alkylNR12R13, C_1-4 alkylOR12, C_1-4 alkylhetaryl or may be joined to form a 5-8 membered ring optionally containing an atom selected from O, S, SO, SO₂, NR14;

RIl is selected from OH, OC_1-4 alkyl, NR12R13;

where R12 and R13 are independently selected from H, C ₁.₄ alkyl, or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR14;

R14 is independently selected from H, C_1-4 alkyl; Y is 0-2 substituents selected from C_1-4alkyl, NR15R16, OH, halogen, C_1-4alkylNR15Rl6;

R15 and R16 are independently selected from H, C_1-4 alkyl.

In a second aspect the present invention provides a pharmaceutical composition comprising a compound according to the first aspect.

In a third aspect the present invention provides a method for the treatment of a tyrosine kinase-associated disease state comprising administering a therapeutically effective amount of a compound according to the first aspect or a therapeutically effective amount of a pharmaceutical composition according to the second aspect.

According to a fourth aspect there is provided a use of a compound according to the first aspect or a pharmaceutical composition according to the second aspect in the manufacture of a medicament for the treatment of a tyrosine kinase-associated disease state.

In a fifth aspect, the present invention provides a method of suppressing the immune system of a subject, the method comprising administering a therapeutically effective amount of at least one compound according to the first aspect or a therapeutically effective amount of a pharmaceutical composition according to the second aspect.

According to a sixth aspect there is also provided a use of a compound according to the first aspect or a therapeutically effective amount of a pharmaceutical composition according to the second aspect in the preparation of a medicament for suppressing the immune system of a subject.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the amino acid sequence alignment of selected Jak Kinases

Figure 2 shows a model of the J ak3 kinase ATF binding pocket displaying the Cysteine residue. DETAILED DESCRIPTION OF THE INVENTION

According to a first aspect of the invention there is provided a compound of the general formula I

I

or pharmaceutically acceptable prodrugs, salts, hydrates, solvates, crystal forms, and isomeric forms selected from the group consisting of conformational isomers, enantiomeric forms, diastereomeric forms, optical isomers, stereoisomers, tautomers and mixtures thereof, wherein:

A can be a bond, NH, O, S, S(O)_n, or can be selected from:

where * represents the point of attachment to the pyridine ring,

where n = 1 or 2; and Rl and R2 are independently selected from H, C_1-4 alkyl, C_2-4alkyl0H, C_2-4alkylNR3R4;

B is alkyl, Q.scycloalkyl, aryl, hetaryl, C_1-4alkylaryl, Cι_-4alkylhetaryl, cyclohetalkyl, substituted with 0-3 substituents independently selected from halogen, C_1-4alkyl, CF₃, CN, aryl, hetaryl, OH, OCF₃, OC_1-4alkyl, OC_2-

₅alkylNR3R4, Oaryl, Ohetaryl, COR3, CO₂R3, CONR3R4, NR3R4, C_{1- 4}alkylNR3R4, NR5C_2-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4, NR3SO₂R4;

R3, R4 are each independently H, C_1-4alkyl, C_1-4alkylcyclohetalkyl, aryl, hetaryl, C_1-4alkylaryl, C_1-4 alkylhetaryl, or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR6;

R5 and R6 are independently selected from H, C_1-4 alkyl;

D is a bond, NH, O, C(O), S(0)_m, C_1-4alkyl, C_2-4alkenyl, alkylcycloalkyl, C_1-4alkylNR7, C_1-4alkylO, C_1-4alkylS(O)_m, where m = 0,1,2;

R7 is selected from H, C_1-4 alkyl, C_2-4alkyl0H, C_2-4alkylNR3R4;

E is aryl, hetaryl, optionally substituted with 0-2 substituents independently selected from halogen, C_1-4 alkyl, CF₃, CN, OH, OCF₃, OCi_-4alkyl, OC_2-5alkylNR3R4, COR3, CO₂R3, CONR3R4, NR3R4, C_1-4alkylNR3R4, NR5C_1-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4, NR3COOR3,

C_1-4alkylNR3COOR3, NR3SO₂R4; and R3, R4, R5 are as described previously;

G is H or selected from:

where # is point of attachment to E;

W is NR8, 0 or a bond;

p is 0-4;

R8 is selected from H, C_1-4 alkyl;

R9 and RlO are independently selected from H, C_1-4 alkyl, aryl, hetaryl, C_1-4alkylNR12R13, C_1-4alkylOR12, C_1-4 alkylhetaryl or may be joined to form a 5-8 membered ring optionally containing an atom selected from O, S, SO, SO₂, NR14;

Rl 1 is selected from OH, OC_1-4 alkyl, NR12R13;

where R 12 and Rl 3 are independently selected from H, C_1-4 alkyl. or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR14;

R14 is independently selected from H, C_1-4 alkyl; Y is 0-2 substituents selected from C_1-4alkyl, NR15R16, OH, halogen, C_1-4alkylNRl5R16;

R15 and R16 are independently selected from H, C_1-4 alkyl.

The compounds of formula I may reversibly or irreversibly inhibit JAK 3. Generally, the strength of binding of reversible inhibitors of an enzyme is measured by the IC₅₀ value which is a reflection of the equilibrium constant of the interaction between the inhibitor and the active site of the enzyme. Irreversible inhibitors display an apparent IC₅₀ because once the inhibitor is bound it will not leave the active site and the measured IC₅₀ will therefore improve (i.e. number will decrease) over time.

Preferably, the compound of formula I selectively inhibits JAK 3 with respect to JAK 1 or JAK 2. The term "selectively inhibits" is defined to mean that the apparent IC₅₀ of the compound for JAK 3 is more than ten-fold lower (i.e. more potent) than the IC₅₀ for JAK 1 or JAK 2.

The compounds of this invention include all conformational isomers (eg. cis and trans isomers). The compounds of the present invention have asymmetric centres and therefore exist in different enantiomeric and diastereomeric forms. This invention relates to the use of all optical isomers and stereoisomers of the compounds of the present invention, and mixtures thereof, and to all pharmaceutical compositions and methods of treatment that may employ or contain them. The compounds of formula I may also exist as tautomers. This invention relates to the use of all such tautomers and mixtures thereof.

This invention also encompasses pharmaceutical compositions containing prodrugs of compounds of the formula I. This invention also encompasses methods of treating or preventing disorders that can be treated or prevented by the inhibition of protein kinases, such as JAK comprising administering prodrugs of compounds of the formula I. Compounds of formula I having free amino, amido, hydroxy or carboxylic groups can be converted into prodrugs. Prodrugs include compounds wherein an amino acid residue, or a polypeptide chain of two or more (eg, two, three or four) amino acid residues which are covalently joined through peptide bonds to free amino, hydroxy and carboxylic acid groups of compounds of formula I. The amino acid residues include the 20 naturally occurring amino acids commonly designated by three letter symbols and also include, A- hydroxyproline, hydroxylysine, demosine, isodemosine, 3-methylhistidine, norvlin, beta- alanine, gamma-aminobutyric acid, citrulline, homocysteine, homoserine, ornithine and methioine sulfone. Prodrugs also include compounds wherein carbonates, carbamates, amides and alkyl esters which are covalently bonded to the above substituents of formula I through the carbonyl carbon prodrug sidechain. Prodrugs also include phosphate derivatives of compounds of formula I (such as acids, salts of acids, or esters) joined through a phosphorus-oxygen bond to a free hydroxyl of compounds of formula I.

Where the compound possesses a chiral centre the compound can be used as a purified isomer or as a mixture of any ratio of isomers. It is however preferred that the mixture comprises at least 70%, 80%, 90%, 95%, or 99% of the preferred isomer.

In a still further preferred embodiment the compound is selected from the compounds set out in Table 3.

In a second aspect the present invention consists in a pharmaceutical composition comprising a carrier and at least one compound of the first aspect of the invention.

In a third aspect the present invention consists in a method of treating a tyrosine kinase- associated disease state, the method comprising administering a therapeutically effective amount of at least one compound of the first aspect of the invention or a therapeutically effective amount of a composition of the second aspect of the invention.

In a further preferred embodiment the tyrosine kinase-associated disease state involves JAKl, JAK2, JAK3 or TYK2.

In a preferred embodiment of the present invention the disease state is selected from the group consisting of Atopy, such as Allergic Asthma, Atopic Dermatitis (Eczema), and Allergic Rhinitis; Cell Mediated Hypersensitivity, such as Allergic Contact Dermatitis and Hypersensitivity Pneumonitis; Rheumatic Diseases, such as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis, Juvenile Arthritis, Sjogren's Syndrome, Scleroderma, Polymyositis, Ankylosing Spondylitis, Psoriatic Arthritis; Other autoimmune diseases such as Type I diabetes, autoimmune thyroid disorders, and Alzheimer's disease; Viral Diseases, such as Epstein Barr Virus (EBV), Hepatitis B, Hepatitis C, HIV, HTLV 1, Varicella-Zoster Virus (VZV), Human Papilloma Virus (HPV), Cancer, such as Leukaemia, Lymphoma and Prostate Cancer.

As used herein the term "tyrosine kinase-associated disease state" refers to those disorders which result from aberrant tyrosine kinase activity, in particular JAK activity and/or which are alleviated by inhibition of one or more of these enzymes.

In a further aspect the present invention provides the use of the compounds and pharmaceutical composition described in the preparation of medicaments for the treatment of JAK3-associated disease states.

In a yet further aspect, the present invention provides for a method of suppressing the immune system of a subject, the method comprising administering a therapeutically effective amount of at least one compound of the first aspect of the invention or a therapeutically effective amount of a composition of the second aspect of the invention.

Preferably, the method of suppressing the immune system is for the treatment of disease states selected from lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, asthma, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, and Alzheimer's disease.

Preferably, the method of suppressing the immune system is to modify the immune system response to a transplant into a subject. More preferably, the transplant is an organ transplant or tissue transplant.

In another aspect, the present invention provides a use of a compound of general formula I or a therapeutically effective amount of a pharmaceutical composition comprising a compound of general formula I in the preparation of a medicament for suppressing the immune system of a subject.

The present invention provides pharmaceutical compositions comprising at least one of the compounds of the formula I capable of treating a JAK3-associated disorder in an amount effective therefore, and a pharmaceutically acceptable vehicle or diluent. The compositions of the present invention may contain other therapeutic agents as described below, and may be formulated, for example, by employing conventional solid or liquid vehicles or diluents, as well as pharmaceutical additives of a type appropriate to the mode of desired administration (for example, excipients, binders, preservatives, stabilizers, flavours, etc.) according to techniques such as those well known in the art of pharmaceutical formulation.

The compounds of the formula I may be administered by any suitable means, for example, orally, such as in the form of tablets, capsules, granules or powders; sublingually; buccally; parenterally, such as by subcutaneous, intravenous, intramuscular, or intracisternal injection or infusion techniques (e.g., as sterile injectable aqueous or non-aqueous solutions or suspensions); nasally such as by inhalation spray; topically, such as in the form of a cream or ointment; or rectally such as in the form of suppositories; in dosage unit formulations containing non-toxic, pharmaceutically acceptable vehicles or diluents. The compounds may, for example, be administered in a form suitable for immediate release or extended release. Immediate release or extended release may be achieved by the use of suitable pharmaceutical compositions comprising the present compounds, or, particularly in the case of extended release, by the use of devices such as subcutaneous implants or osmotic pumps.

In addition to primates, such as humans, a variety of other mammals can be treated according to the method of the present invention. For instance, mammals including, but not limited to, cows, sheep, goats, horses, dogs, cats, guinea pigs, rats or other bovine, ovine, equine, canine, feline, rodent or murine species can be treated. However, the method can also be practiced in other species, such as avian species (e.g., chickens).

Diseases and conditions associated with inflammation and infection can be treated using the method of the present invention. In a preferred embodiment, the disease or condition is one in which the actions of eosinophils and/or lymphocytes are to be inhibited or promoted, in order to modulate the inflammatory response. 01799

23.

The subjects treated in the above methods, in whom which JAK3 inhibition is desired, are mammals, including, but not limited to, cows, sheep, goats, horses, dogs, cats, guinea pigs, rats or other bovine, ovine, equine, canine, feline, rodent or murine species, and preferably a human being, male or female.

The term "therapeutically effective amount" means the amount of the subject composition that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician.

The term "composition" as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. By "pharmaceutically acceptable" it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The terms "administration of" and or "administering a" compound should be understood to mean providing a compound of the invention to the individual in need of treatment.

The pharmaceutical compositions for the administration of the compounds of this invention may conveniently be presented in dosage unit form and may be prepared by any of the methods well known in the art of pharmacy. All methods include the step of bringing the active ingredient into association with the carrier which constitutes one or more accessory ingredients. In general, the pharmaceutical compositions are prepared by uniformly and intimately bringing the active ingredient into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product into the desired formulation. In the pharmaceutical composition the active object compound is included in an amount sufficient to produce the desired effect upon the process or condition of diseases. As used herein, the term "composition" is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. The pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavouring agents, colouring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate may be employed. They may also be coated to form osmotic therapeutic tablets for control release.

Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxy-propylmethylcellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n- propyl, p-hydroxybenzoate, one or more colouring agents, one or more flavouring agents, and one or more sweetening agents, such as sucrose or saccharin.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavouring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavouring and colouring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally- occurring gums, for example gum acacia or gum tragacanth, naturally- occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening and flavouring agents. Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavouring and colouring agents.

The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleagenous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally- acceptable diluent or solvent, for example as a solution in 1,3-butane diol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or diglycerides. hi addition, fatty acids such as oleic acid find use in the preparation of injectables.

The compounds of the present invention may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non- irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.

For topical use, creams, ointments, jellies, solutions or suspensions, etc., containing the compounds of the present invention are employed. (For purposes of this application, topical application shall include mouthwashes and gargles.)

The compounds of the present invention can also be administered in the form of liposomes. As is known in the art, liposomes are generally derived from phospholipids or other lipid substances. Liposomes are formed by mono- or multilamellar hydrated liquid crystals that are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable and metabolisable lipid capable of forming liposomes can be used. The present compositions in liposome form can contain, in addition to a compound of the present invention, stabilisers, preservatives, excipients and the like. The preferred lipids are the phospholipids and phosphatidyl cholines, both natural and synthetic. Methods to form liposomes are known in the art.

The pharmaceutical composition and method of the present invention may further comprise other therapeutically active compounds as noted herein which are usually applied in the treatment of the above mentioned pathological conditions. Selection of the appropriate agents for use in combination therapy may be made by one of ordinary skill in the art, according to conventional pharmaceutical principles. The combination of therapeutic agents may act synergistically to effect the treatment or prevention of the various disorders described above. Using this approach, one may be able to achieve therapeutic efficacy with lower dosages of each agent, thus reducing the potential for adverse side effects.

Examples of other therapeutic agents include the following:

cyclosporins (e.g., cyclosporin A), CTLA4-Ig, antibodies such as ICAM-3, anti-IL-2 receptor (Anti-Tac), anti-CD45RB, anti-CD2, anti-CD3 (OKT-3), anti-CD4, anti-CD80, anti-CD86, agents blocking the interaction between CD40 and gp39, such as antibodies specific for CD40 and/or gp39 (i.e., CD154), fusion proteins constructed from CD40 and gp39 (CD401g and CD8gp39), inhibitors, such as nuclear translocation inhibitors, of NF-kappa B function, such as deoxyspergualin (DSG), cholesterol biosynthesis inhibitors such as HMG CoA reductase inhibitors (lovastatin and simvastatin), non-steroidal antiinflammatory drugs (NSAIDs) such as ibuprofen, aspirin, acetaminophen, leflunomide, deoxyspergualin, azathioprine and cyclooxygenase inhibitors such as rofecoxib and celecoxib, steroids such as prednisolone or dexamethasone, gold compounds, antiproliferative agents such as methotrexate, FK506 (tacrolimus, Prograf), mycophenolate mofetil, cytotoxic drugs such as azathioprine, VP- 16, etoposide, fludarabine, cisplatin and cyclophosphamide, TNF-a inhibitors such as tenidap, anti-TNF antibodies or soluble TNF receptor, and rapamycin (sirolimus or Rapamune) or derivatives thereof.

When other therapeutic agents are employed in combination with the compounds of the present invention they may be used for example in amounts as noted in the Physician Desk Reference (PDR) or as otherwise determined by one of ordinary skill in the art. In the treatment or prevention of conditions which require protein tyrosine kinase inhibition an appropriate dosage level will generally be about 0.01 to 500 mg per kg patient body weight per day which can be administered in single or multiple doses. Preferably, the dosage level will be about 0.1 to about 250 mg/kg per day; more preferably about 0.5 to about 100 mg/kg per day. A suitable dosage level may be about 0.01 to 250 mg/kg per day, about 0.05 to 100 mg/kg per day, or about 0.1 to 50 mg/kg per day. Within this range the dosage may be 0.05 to 0.5, 0.5 to 5 or 5 to 50 mg/kg per day. For oral administration, the compositions are preferably provided in the form of tablets containing 1.0 to 1000 milligrams of the active ingredient,^" particularly 1.0, 5.0, 10.0, 15.0. 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 milligrams of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.

It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

In order that the nature of the present invention may be more clearly understood, preferred forms thereof will now be described with reference to the following non-limiting examples.

EXAMPLES

MATERIALS AND METHODS:

Compound Synthesis

The present compounds may be prepared in general by methods known to those skilled in the art, as illustrated by Schemes and the synthetic examples shown below. The formation of the amide II is typically achieved by coupling an amine with the nicotinic acid I using coupling reagents such as dicyclohexylcarbodiimide, l-(3- dimethylaminopropyl)-3-ethylcarbodiimide, diisopropylcarbodiimide or carbonyldiimidazole in solvents such as dichloromethane, tetrahydrofuran or 1,4-dioxane.

Scheme 1

Alternatively, the nicotinic acid I can be converted to the respective acid chloride using thionyl chloride, oxalyl chloride, bis(trichloromethyl)carbonate or cyanuric chloride, or to the mixed anhydride species using, for example, t-butyl chloroformate, using procedures well known to those skilled hi the art. The acid chloride or mixed anhydride derivatives can then be reacted with the desired amine preferably in the presence of a base such as triethylamine, diisopropylethylarnine or solid phase equivalent in a solvent such as dichloromethane, tetrahydrofuran, dioxane or ethyl acetate at ambient or elevated temperatures, to generate the desired nicotinamide II. The acid chloride may also react with the required amine under aqueous conditions preferably in the presence of an inorganic base such as sodium hydroxide, potassium hydroxide or sodium carbonate to generate the desired nicotinamide II.

As a further alternative, the nicotinic acid I can be converted to the corresponding active ester intermediate, such as the N-hydroxysuccinimidyl, pentafluorophenyl or p-nitrophenyl esters. This can be achieved by coupling the nicotinic acid 1 with N-hydroxysuccinimide, pentafluorophenol or p-nitrophenol using coupling reagents such as dicyclohexylcarbodiimide, l-(3-dmiethylaminopropyl)-3-ethylcarbodiimide, diisopropylcarbodiimide or carbonyldiimidazole in solvents such as dichloromethane and tetrahydrofuran. Active acyl intermediates can also be formed directly by. reaction of the 5-arylnicotinic acid derivatives with reagents such as diphenylphosphoryl azide, pentafluorophenyl acetate, pentafluorophenyl diphenylphosphinate, diphenylphosphinyl chloride or cyanuric chloride using methods well known to those skilled in the art. The active ester thus formed is then reacted, either in situ, or after isolation, with the desired amine preferably in the presence of a base such as triethylamine, diisopropylethylamine or solid phase equivalent in a solvent such as dichloromethane, tetrahydrofuran, dimethylformamide, dioxane or ethyl acetate at ambient or elevated temperatures, to generate the desired nicotinamide II.

The synthesis of carbamates III and ureas IV may be undertaken also starting from nicotinic acid I by formation of the acyl azide V (Scheme 2). Acyl azide V may be prepared from I by reaction with diphenylphosphoryl azide generally in a solvent such as toluene or tetrahydrofuran in the presence of a base such as triethylamine or diisopropylethylamine. Other routes to acyl azides include reaction of the acid chloride, derived from I, with sodium azide, reaction of nitrous acid and acid hydrazides derived from I, and reaction of the mixed carboxylic-carbonic anhydride, derived from I and ethyl chlorocarbonate, with sodium azide. Heating the acyl azide V in the presence of an alcohol or amine then leads to the desired carbamate III or urea IV, respectively, via a modified Curtius rearrangement.

Scheme 2

IV

The t-butyl carbonate III (R = t-Bu) may also be used in the preparation of ureas IV. For example, reaction of III with a non-nucleophilic base such as DMAP or 4- pyrrolidinopyridine followed by addition of an amine, following the procedure of Knolker et al (Knolker 1996), may furnish the ureas IV. Alternatively, treatment of the t-butyl carbonate III (R = t-Bu) with an acid such as trifluoroacetic acid or hydrochloric acid will generate the primary amine VI (Scheme 3). Generally such a reaction is carried out neat or in a solvent such as dichloromethane or tetrahydrofuran, at room temperature to reflux. Methods to convert an aniline VI to a urea are well-known to those skilled in the art and include reaction with isocyanates and reaction with phosgene (or a phosgene equivalent) followed by addition of an amine.

Scheme 3

The aniline VI may also be used in the preparation of compounds of formula VII, where B is defined as above. For example, the aniline may react as a nucleophile in a classical nucleophilic substitution reaction with a suitable partner. Suitable reaction partners would include heteroaromatic halides and cycloalkyl halides. Such reactions are typically carried out in solvents such as acetonitrile, dimethylformamide or xylene at reflux, or neat at elevated temperatures, typically in the presence of a base such as sodium carbonate, potassium carbonate, caesium carbonate, diisopropylethylamine or pyridine (Scheme 4).

Scheme 4

VII

If B is aryl or heteroaryl, then it may be prepared from the aniline VI by coupling of VI with a suitable aryl or hetaryl coupling partner. Such coupling partners include aryl and hetaryl halides and triflates and the reaction is generally performed using catalytic systems typically selected from Pd(OAc)₂/P(t-Bu)₃, Pd₂(dba)₃/BINAP, Pd(O Ac)₂/B INAP, CuFK₂CO₃, Cu₂O, Cu(PPh₃)₃Br, Cu(phen)(PPh₃)Br.

Alternatively compounds VII can be prepared by a copper catalysed reaction between the aniline VI and an organometallic reagent (see for example Finet, 2002). Preferable organometallic reagents are boronic acids.

Amides VIII are preferably prepared from the aniline VI by methods well known to those skilled in the art (Scheme 5). Preferable methods include coupling the aniline VI with respective acids I using coupling reagents such as dicyclohexylcarbodiimide, l-(3- dimethylaminopropyl)-3-ethylcarbodiimide, diisopropylcarbodiimide or carbonyldiimidazole in solvents such as dichloromethane, tetrahydrofuran or 1,4-dioxane. Alternatively, the acid may be activated by conversion to an acid chloride (using methods outlined above) or to mixed anhydride species (using procedures described above) or to active ester intermediates (using procedures described above). The active species thus formed is reacted with the aniline VI preferably in the presence of a base such as triethylamine, diisopropylethylamine or solid phase equivalent in a solvent such as dichloromethane, tetrahydrofuran, dioxane or ethyl acetate at ambient or elevated temperatures, to generate the desired amide VIII.

Scheme 5

The bromopyridine species prepared above are then reacted further such that the bromine is replaced by the groups D-E-G (described above). For example, the bromine can be substituted for an aryl or hetaryl ring via a transition metal mediated cross-coupling reaction. For example, the formation of the amides X from the 5-bromonicotinamide II is achieved by reaction with a suitably functionalised coupling partner IX. Typical coupling partners are boronic acids or esters (Suzuki coupling: see for example Miyaura and Suzuki 1995), organostannanes (Stille coupling: see for example Stille 1986), Grignard reagents (Kumada coupling: Kumada, Tamao and Sumitani 1988) or organozinc species (Negishi coupling: Negishi 2002) (Scheme 6).

Scheme 6

The Suzuki coupling is the preferred coupling method and is typically performed in a solvent such as DME, THF, DMF, ethanol, propanol, toluene, or 1,4-dioxane in the presence of a base such as potassium carbonate, sodium carbonate, lithium hydroxide, caesium carbonate, sodium hydroxide, potassium fluoride or potassium phosphate. The reaction may be carried out at elevated temperatures and the palladium catalyst employed may be selected from Pd(PPh₃)₄, Pd(OAc)₂, [PdCl₂(dppf)], Pd₂(dba)₃/P(t-Bu)₃, Pd/C, Pd(OH)₂/C.

Replacement of the bromine atom in the compounds described above with a thiol moiety may be achieved by a palladium catalysed reaction between triisopropylsilylthiol and the appropriate bromide following the method of Soderquist (Soderquist, 1994). The thiol thus formed can then react under copper-catalysis with aryl and hetaryl boronic acids to give pyridyl aryl thioethers or pyridyl hetaryl thioethers (see for example, Herradura, 2000). Alternatively, such thioethers may be prepared directly from the copper-catalysed coupling of the bromides described above and appropriate aryl and hetaryl thiols (see for example, Bates 2002). Scheme 7

The bromine atom of the bromopyridine species prepared above may also be replaced through transition metal mediated coupling with anilines or phenols, using procedures known to those skilled in the art. For example, anilines XI (X = NH₂) can couple with the bromopyridine species described above under palladium catalysis, such as Pd₂(dba)₃ and Pd(dppf)Cl₂, in the presence of phosphine ligands such as BINAP and in the presence of a base such as sodium t-butoxide or caesium carbonate (Buchwald-Hartwig reaction: see for example Hartwig 1998) (Scheme 8). Similarly, the reaction can be performed using copper catalysis (Ullmann reaction: see for example Lindley, 1984)

Likewise, diaryl ethers XII (X = O) can be prepared by palladium or copper catalysis (using procedures analogous to those reported above for the synthesis of diaryl amines XII [X = NH]) using phenols XI (X = OH) as the coupling partner (Scheme 8). Scheme 8

The thiol reactive moiety present in compounds 1 of the invention may be already present in the functionalities employed in the synthetic processes described above or may be introduced at the final stage of the synthetic procedure. For example, the thiol reactive moiety may be introduced in compounds XIII (W = OH, NH₂) by coupling with a suitable acid. This is typically achieved using coupling reagents such as dicyclohexylcarbodiimide, 1 -(3 -dimethylaminopropyl)-3 -ethylcarbodiimide, diisopropylcarbodiimide or carbonyldiimidazole in solvents such as dichloromethane, tetrahydrofuran or 1,4-dioxane. Alternatively, suitable mixed anhydride species of the acid, formed using, for example, t- butyl chloroformate, using procedures well known to those skilled in the art, or a suitable acid chloride derivative, can be reacted with the amine or alcohol XIII in the presence of a base such as triethylamine, diisopropylethylamine or solid phase equivalent in a solvent such as dichloromethane, tetrahydrofuran, dioxane or ethyl acetate at ambient or elevated temperatures, to generate the desired compound of general formula XIV. (Scheme 9)

Scheme 9

As another alternative, the suitable acid derivatives can be converted to the corresponding active ester intermediates, such as the succinimidyl, pentafluorophenyl or p-nitrophenyl esters. This can be achieved by coupling the corresponding acid derivatives with N- hydroxysuccinimide, pentafluorophenol or p-nitrophenol using coupling reagents such as dicyclohexylcarbodiimide, l-(3-dimemylammopropyl)-3-ethylcarbodiimide, diisopropylcarbodiimide or carbonyldiimidazole in solvents such as dichloromethane and tetrahydrofuran. Active acyl intermediates can also be formed directly by reaction of the suitable acid derivatives with reagents such as diphenylphosphoryl azide, pentafluorophenyl acetate, pentafluorophenyl diphenylphosphinate or cyanuric chloride using methods well known to those skilled in the art.

Those skilled in the art will appreciate that the order of the reactions described for the syntheses above may be changed in certain circumstances and that certain functionalities may need to be derivatised (i.e. protected) in certain instances for the reactions described above to proceed with reasonable yield and efficiency. The types of protecting functionality are well-known to those skilled in the art and are described for example in Greene (Greene, 1999). The products formed from the reaction sequences described above may be further derivatised using techniques well known to those skilled in the art.

Representative syntheses are reported below.

Example 1

5-Bromo-N-(2,6-dimethylphenyl)nicotinamide

Thionyl chloride (6OmL) was added to 5-bromonicotinic acid (12g, 59.4mmoi) followed by N,N-dimethylformamide (3 drops, cat.) and the mixture was heated to reflux for 16 hours. The reaction mixture was allowed to cool and then the excess thionyl chloride was removed by distillation. To the residue was added toluene (3OmL) and the toluene removed under reduced pressure on a rotary evaporator. This step was repeated to produce 5-bromonicotinoyl chloride (13.Og). The crude acid chloride was dissolved in anhydrous 1,4-dioxane (10OmL) to which was added 2,6-dimethylaniline (7.15g, 58.97mmol). After stirring at room temperature for 15 min. diisopropylethylamine (11.92mL, 68.41mmol) was added and the resultant solution was stirred at room temperature for 5 hours. The volatiles were then removed under reduced pressure on a rotary evaporator. The crude residue was dissolved in ethyl acetate (10OmL) and washed with IN HCl solution (2xl00mL), waiter (10OmL), saturated sodium bicarbonate solution (10OmL) and brine (10OmL), dried (Na₂SO₄) and re-concentrated in vacuo. The residue was recrystallized from ethyl acetate/ether to afford the product.

Example 2

5-(3-Aminophenyl)-N-(2, 6-dimethylphenyl)nicotinamide

To a solution of 2,6-dimethylphenyl 5-bromonicotinamide (2.Og, 6.55mmol) in a mixture of toluene (6OmL) and 1-propanol (3OmL) was added 3-aminophenylboronic acid (1.46g, 9.44mmol), 2M aqueous sodium carbonate (6.75mL, 13.5mmol) and tetrakis(triphenyl- phosphine)palladium(O) (0.757g, 0.66mmol). The reaction mixture was placed under an atmosphere of nitrogen and heated to reflux for 16 hours. The reaction mixture was allowed to cool, and then concentrated under reduced pressure. The residue was dissolved in ethyl acetate (20OmL), washed with water (2xl00mL) and brine (10OmL), then dried (Na₂SO₄) and concentrated under reduced pressure. The crude residue was recrystallized from ethyl acetate/ether to provide 1.54g of product.

Example 3

5-[3-(Acryloylamino)phenyl]-N-(2,6-dimethylphenyl)nicotinamide

To a solution of acrylic acid (17.4 mg, 0.24mmol) in 1,4-dioxane (0.5mL) was added a solution of cyanuric chloride (14.9mg, 0.08mmol) in dioxane (1.OmL) followed by triethylamine (34μL, 0.24mmol). The mixture was shaken for 15 min. at ambient temperature, then a solution of 5-(3-aminophenyl)-N-(2,6-dimethylphenyl)nicotinamide (40mg, 0.12mmol) in 1,4-dioxane (1.OmL) was added. The resultant mixture was shaken whilst heating at 50°C for 16 hours. The cooled mixture was filtered through a bed of silica gel and then concentrated in vacuo to give the desired product. Example 4

tert-Butyl 3-(5-{[(2, 6-dimethylphenyl)amino]carbonyl}pyridin~3-yl)benzyl carbamate

tert-Butyl 3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-benzyl carbamate (1.73g, 5.19mmol) and 5-bromo-N-(2,6-dimethylphenyl)nicotinamide (l.lg, 3.60mmol) were reacted together using the procedure outlined in Example 2. The crude material was recrystallized from ethyl acetate/ether to provide the product.

Example 5

5-[(3-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide

tert-Butyl 3-(5-{ [(2,6-dimethylphenyl)amino]carbonyl}pyridin-3-yl)benzyl carbamate from the previous example was treated with a 20% solution of trifiuoroacetic acid in dichloromethane (2OmL) and stirred at ambient temperature for 1.5 hours. The reaction solution was concentrated under reduced pressure then re-dissolved in dichloromethane and washed with saturated sodium bicarbonate solution, dried (MgSO₄) and concentrated in vacuo. This provided 1.65g of the title compound.

Example 6

5-{3-[(Acryloylamino)methyl]phenyl}-N-(2,6-dimethylphenyl)nicotinamide

5-[(3-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide (40mg, 0.12mmol) and acrylic acid (17mg, 0.24mmol) were reacted together as described in Example 3. The crude product was filtered through a bed of silica gel to provide 14.7 mg of the title compound.

Example 7

N-(2,6-Dimethylphenyl)-5-f3-[(vinylsulfonyl)amino]phenylJnicotinamide

To a solution of 5-(3-aminophenyl)-N-(2,6-dimethylphenyl)nicotinamide (50mg, O.lόmmol) and diisopropylethylamine (24.4mg, 0.19mmol) in dichloromethane (ImL) was added a solution of 2-chloroethanesulfonyl chloride (22mg, 0.17mmol) in dichloromethane (0.5mL). The reaction vial was sealed and heated to 6O⁰C for 16 hours whilst shaking, then allowed to cool to ambient temperature. The reaction mixture was then washed with saturated NaHCO₃ solution (2x5mL), dried (Na₂CO₃) and concentrated under reduced pressure. Purification by chromatography on silica gel provided the title compound.

Example 8

N-(2,6-Dimethylphenyl)-5-(3-{[(vinylsulfonyl)amino]methyl}phenyl)nicotinamide

5-[(3-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide (lOOmg, 0.3mmol) and 2-chloroethanesulfonyl chloride (32μL, 0.33mmol) were reacted together as described in Example 7. The crude material was chromatographed on silica gel to provide the title compound.

Example 9

5-(4-Aminophenyl)-N-(2, 6-dimethylphenyl)nicotinamide

2,6-Dimethylphenyl 5-bromonicotinamide (2.7g, 8.85mmol) and 4-aminophenylboronic acid (2.79g, 12.74mmol) were reacted together using the method described in Example 2. The crude product was recrystallized from ethyl acetate/ether to give the title compound.

Example 10

tert-Butyl 4-(5-f[(2, 6-dimethylphenyl)amino]carbonyl}pyridin-3-yl)benzyl carbamate

tert-Butyl 4-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-benzyl carbamate (1.73g, 5.19mmol) and 5-bromo-N-(2,6-dimethylphenyl)nicotinamide (l.lg, 3.60mmol) were reacted together using the procedure outlined in Example 2. The crude material was chromatographed on silica gel to provide 2.Og of the title compound. Example 11

5-[(4-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide

tert-Butyl 4-(5-{ [(2,6-dimethylphenyl)amino]carbonyl}pyridin-3-yl)benzyl carbamate from the previous example was treated with a 20% solution of trifluoroacetic acid in dichloromethane (2OmL) as described in Example 5 to give 1.65g of product.

Example 12

5-[4-(Acryloylamino)phenyl]-N-(2,6-dimethylphenyl)nicotinamide

5-(4-aminophenyl)-N-(2,6-dimethylphenyl)nicotinamide (50mg, O.lθmmol) and acrylic acid (22μL, 0.32mmol) were reacted together as described in Example 3. The crude product was chromatographed on silica gel (3:2 ethyl acetate:pet. ether) to provide 6.7mg of the title compound.

Example 13

5-{4-[(Acryloylamino)methyl]phenyl}-N-(2,6-dimethylphenyl)nicotinamide

5-[(4-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide (40mg, 0.12mmol) and acrylic acid (17.4mg, 0.24mmol) were reacted together as described in Example 3. This provided 14.0 mg of the title compound.

Example 14

N-(2,6-Dimethylphenyl)-5-{4-[(vinyl$ulfonyl)amino]phenyl}nicotinamide

5-(4-aminoplienyl)-N-(2,6-dimethylphenyl)nicotinamide (50mg, O.lόmmol) and 2-chloroethanesulfonyl chloride (22mg, 0.17mmol) were reacted together as described in Example 7. The crude material was chromatographed on silica gel to provide the title compound. Example 15

N-(2,6-Dimethylphenyl)-5-(4-{[(vinylsulfonyl)amino]methylJphenyl)nicotinamide

5-[(4-Aminomethyl)phenyl]-N-(2,6-dimethylphenyl)nicotinamide (lOOmg, 0.3mmol) and 2-chloroethanesulfonyl chloride (32μL, O.33mmol) were reacted together as described in Example 7. The crude material was chromatographed on silica gel to provide the title compound.

Compound Characterisation

LC-MS data was acquired on a Waters 2795 Alliance HPLC coupled to a Waters 2996 Photodiode Array Detector (set to 210-400 nm) and Integrity TMD Electron Impact Mass Spectrometer operating under control of Waters Millenium software version 4.0 with the settings outlined below.

Mass spectrometer parameters: Helium flow of approximately 0.36 L/min; acquisition mode set to scan; sampling rate of 1 spectra/sec; source temperature 200°C; nebuliser temperature 80°C; expansion region temperature 75°C; mass range m/z 100-550.

HPLC parameters: Flow rate: 0.25 rnL/min; column temperature: ambient (~25°C);

Column: XTerra MS C₁₈, 3.5 micron, 3.0 x 100 mm; or Alltima HP C₁₈, 5 micron 2.1 x l^'50 mm.

Solvent gradient:

Time % MiIIiQ water % ACN Curve

0 90 10

7 0 100 6

9 0 100 6

10 90 10 6

13 90 10 6 Selected ¹H-NMR Data for compounds in Table 3

Compound 1 (C22H21N3O3S):

¹H-NMR(CDCl₃): δ 9.13(m, IH), 8.99(m, IH), 8.43(m, IH), 7.46(m, 4H), 7.16(m, 3H), 6.60(dd, IH), 6.34(d, IH), 6.00(d, IH), 2.32(s, 6H).

Compound 4 (C24H23N3O2):

¹H-NMR(CD₃OD): δ 9.14(d, IH), 8.98(d, IH), 8.60(m, IH), 7.65(m, 2H), 7.52(t, IH), 7.43(m, IH), 7.16(m, 3H), 6.29(m, 2H), 5.69(dd, IH), 4.57(s, 2H), 2.3 l(s, 6H).

Compound 8 (C23H21N3O2):

¹H-NMR(CD₃OD): δ 9.1 l(d, IH), 8.96(d, IH), 8.59(m, IH), 7.84(m, 2H), 7.70(m, 2H), 7.15(m, 3H), 6.44(m, 2H), 5.79(dd, IH), 2.3 l(s, 6H). Compound 9 (C23H23N3O3S):

¹H-NMR(CD₃OD): δ 9.13(d, IH), 8.95(d, IH), 8.58(m, IH), 7.69(d, 2H), 7.52(d, 2H), 7.49(bs, IH), 7.15(m, 3H), 6.55(dd, IH), 6.22(d, IH), 5.93(d, IH), 4.23(s, 2H), 2.31(s, 6H).

Table 3: Characterisation Data for selected Compounds

Table 3: Characterisation Data for selected Compounds (cont.)

Table 3: Characterisation Data for selected Compounds (cont.)

SCREENING

Compound Dilution

For screening purposes, compounds were diluted in 96 well plates at a concentration of 20 μM. Plates were warmed at 37°C for 30 minutes before assay.

JAK Tyrosine Kinase Domain Production

JAK kinase domains were produced in the following manner:

JAKl

The kinase domain of human JAKl was amplified from U937mRNA using the polymerase chain reaction with the following primers:

XHOI-Jl 5'-CCG CTC GAG ACT GAA GTG GAC CCC ACA CAT-S'

Jl-KPNI 5'-CGG GGT ACC TTA TTT TAA AAG TGC TTC AAA-3'

JAKl PCR products were cloned into the pFastBac HTb expression vector (Gibco) via the Xho I and Kpn I sites. The JAKl plasmid was then transformed into competent DHlOBac cells (Gibco), and the recombinant baculovirus produced prepared for transfection into Sf9 insect cells.

JAK2

The kinase domain of humanJAK2 was amplified from U937mRNA using the polymerase chain reaction with the following primers:

SALI-jk2 5'-ACG CGT CGA CGG TGC CTT TGA AGA CCG GGA T-3^*

jk2-N0TI S'-ATA GTT TAG CGG CCG CTC AGA ATG AAG GTC ATT T-S'

JAK2 PCR products were cloned into the pFastBac HTc expression vector (Gibco) via the Sal I and Not I sites. The JAK2 plasmid was then transformed into competent DHlOBac cells (Gibco), and the recombinant baculovirus produced prepared for transfection into Sf9 insect cells.

JAK3

The kinase domain of humanJAK3 was amplified from U937mRNA using the polymerase chain reaction with the following primers:

XHOI-J3 5'-CCG CTC GAGTAT GCC TGC CAAGAC CCCACG-3'

J3-KPNI 5'-CGG GGT ACC CTATGA AAAGGACAG GGA GTG-3'

JAK3 PCR products were cloned into the pFastBac HTb expression vector (Gibco) via the Xho I and Kpn I sites. The JAK3 plasmid was then transformed into competent DHlOBac cells (Gibco), and the recombinant baculovirus produced prepared for transfection into Sf 9 insect cells.

TYK2

The kinase domain of humanTYK2 was amplified from A549 mRNA using the polymerase chain reaction with the following primers:

HT2EK 5'-GGA GCA CTC GAG ATG GTA GCA CAC AAC CAG GTG-S'

ITY2.2R 5'-GGA GCA GGA ATT CCG GCG CTG CCG GTC AAA TCT GG-3 '

TYK2 PCR products were cloned into pBlueBacHis2A (Invitrogen) via the EcoRI site. The recombinant TYK2 baculovirus produced was prepared for transfected into Sf9 insect cells.

Large Scale Production Of Kinase Domains

Baculovirus preparations from each of the JAK family members were infected into five litres of High Five cells (Invitrogen) grown in High Five serum free medium (Invitrogen) to a cell density of approximately 1-2 X 10⁶ cells/ml. Cells are infected with virus at a MOI of 0.8-3.0. Cells were harvested and lysed. JAK kinase domains were purified by affinity chromatography on a Probond (Invitrogen) nickel chelate affinity column.

Assay Protocols

Kinase assays were performed either in a 96 well capture-based ELISA assay or in 384 well Optiplates (Packard) using an Alphascreen Protein Tyrosine Kinase kit. hi either casse using approximately 1.5 μg of affinity purified PTK domain in the presence of 5OmM HEPES, pH 7.5, 1OmM MgCl₂, 15OmM NaCl and lOμM-lmM ATP. The biotinylated substrate biotin-EGPWLEEEEEAYGWMDF-NH₂ (final concentration 5μM) was used as substrate. In the ELISA assay tyrosine phosphorylation was quantitated following transfer to an avidin coated ELISA plate using peroxidase-linked anti-phospho-tyrosine antibody PY20. In the Alphascreen assay, Alphascreen phosphotyrosine acceptor beads followed by streptavidin donor beads were added under subdued light. The ELISA plates were read on a BMG Fluorostar, the Alphascreen plates were read on a Packard Fusion Alpha. Inhibitors were added to the assays fifteen minutes prior to the addition of ATP. Inhibitors were added in aqueous DMSO, with DMSO concentrations never exceeding 1%.

Results

The activity of selected compounds is shown in Table 4. Compounds that exhibited a capacity to inhibit 50% of JAK activity at a concentration of 20μM (measured under standard conditions, see Methods), are designated as "+".

Table 4

CHEMISTRY Jak3 activity

C22H21N3O3S

C22H21 N3O3S

C23H23N3O3S

C23H23N3O3S

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

All publications mentioned in this specification are herein incorporated by reference. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of each claim of this application.

It will be appreciated by persons skilled in the art that numerous variations and/or . modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

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Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A compound of the general formula I

I

or pharmaceutically acceptable prodrugs, salts, hydrates, solvates, crystal forms, and isomeric forms selected from the group consisting of conformational isomers, enantiomeric forms, diastereomeric forms, optical isomers, stereoisomers, tautomers and mixtures thereof, wherein:

A can be a bond, NH, O, S, S(O)_n, or can be selected from:

where * represents the point of attachment to the pyridine ring,

where n = 1 or 2; and Rl and R2 are independently selected from H, C_1-4 alkyl, C₂.₄alkyl0H, C₂.₄alkylNR3R4;

B is alkyl, C₃_₈cycloalkyl, aryl, hetaryl, Ci_-4alkylaryl, Ci_-4alkylhetaryl, cyclohetalkyl, substituted with 0-3 substituehts independently selected from halogen, C^alkyl, CF₃, CN, aryl, hetaryl, OH, OCF₃, OC_1-4alkyl, OC₂-

₅alkylNR3R4, Oaryl, Ohetaryl, C0R3, CO₂R3, CONR3R4, NR3R4, C_{1- 4}alkylNR3R4, NR5C_2-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4, NR3SO₂R4;

R3, R4 are each independently H, C_1-4alkyl, C_1-4alkylcyclohetalkyl, aryl, hetaryl, C^alkylaryl, C_1-4 alkylhetaryl, or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR6;

R5 and R6 are independently selected from H, C_1-4 alkyl;

D is a bond, NH, O, C(O), S(O)_m, C_1-4alkyl, C_2-4alkenyl, alkylcycloalkyl, C_1-4alkylNR7, C_1-4alkyl0, C_1-4alkylS(O)_m, where m = 0, 1,2;

R7 is selected from H, C_1-4 alkyl, C_2-4alkylOH, C_2-4alkylNR3R4;

E is aryl, hetaryl, optionally substituted with 0-2 substituents independently selected from halogen, C_1-4 alkyl, CF₃, CN, OH, OCF₃, OC_1-4alkyl, OC_2-5alkylNR3R4, COR3, CO₂R3, CONR3R4, NR3R4, C_1-4alkylNR3R4, NR5C_1-4alkylNR3R4, NR3COR4, OC(O)NR3R4, NR5CONR3R4, NR3COOR3,

Ci_-4alkylNR3COOR3, NR3SO₂R4; and R3, R4, R5 are as described previously;

G is H or selected from:

where # is point of attachment to E;

W is NR8, 0 or a bond;

p is 0-4;

R8 is selected from H, C_1-4 alkyl;

R9 and RlO are independently selected from H, C_1-4 alkyl, aryl, hetaryl, C_1-4alkylNR12R13, C_1-4alkyl0R12, C_1-4 alkylhetaryl or may be joined to form a 5-8 membered ring optionally containing an atom selected from O, S, SO, SO₂, NR14;

RIl is selected from OH, OC_1-4 alkyl, NR12R13;

where R 12 and Rl 3 are independently selected from H, C_1-4 alkyl, or may be joined to form an optionally substituted 3-8 membered ring optionally containing an atom selected from O, S, NR14;

R14 is independently selected from H, C_1-4 alkyl; Y is 0-2 substituents selected from C_1-4alkyl, NR15R16, OH, halogen, C_1-4alkylNR15R16;

R15 and R16 are independently selected from H, C_1-4 alkyl.

2. A compound according to claim 1, wherein G is selected from the group consisting of:

3. A compound according to claim 1 selected from the group consisting of:

60.

61.

A compound according to any one of claims 1 to 3, wherein the mixture comprises at least 70% of the preferred isomer.

5. A compound according to any one of claims 1 to 4, wherein the compound is selective for the inhibition of JAK3 with respect to JAKl or JAK2.

6. A pharmaceutical composition comprising a compound according to any one of claims 1 to 5 and a pharmaceutically acceptable carrier.

7. A method for the treatment of a tyrosine kinase-associated disease state comprising administering a therapeutically effective amount of a compound according to any one of claims 1 to 5 or a therapeutically effective amount of a pharmaceutical composition according to claim 6.

8. The method according to claim 7, wherein the tyrosine kinase-disease state involves JAKl, JAK2, JAK3 or TYK2.

9. The method according to claim 9, wherein the protein kinase-disease state involves JAK3.

10. The method according to any one of claims 7 to 9, wherein the tyrosine kinase- disease state is selected from the group consisting of Atopy, such as Allergic Asthma, Atopic Dermatitis (Eczema), and Allergic Rhinitis; Cell Mediated

Hypersensitivity, such as Allergic Contact Dermatitis and Hypersensitivity Pneumonitis; Rheumatic Diseases, such as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis, Juvenile Arthritis, Sjogren's Syndrome, Scleroderma, Polymyositis, Ankylosing Spondylitis, Psoriatic Arthritis; Other autoimmune diseases such as Type I diabetes, autoimmune thyroid disorders, and Alzheimer's disease; Viral Diseases, such as Epstein Barr Virus (EBV), Hepatitis B, Hepatitis C, HIV, HTLV 1, Varicella-Zoster Virus (VZV),. Human Papilloma Virus (HPV), Cancer, such as Leukaemia, Lymphoma and Prostate Cancer.

11. Use of a compound of any one of claims 1 to 5 or a pharmaceutical composition according to claim 6 or claim 7 in the manufacture of a medicament for the treatment of a tyrosine kinase-associated disease state.

12. The use according to claim 11, wherein the tyrosine kinase-disease state involves JAKl, JAK2, JAK3 or TYK2.

>

13. The use according to claim 12, wherein the tyrosine kinase-disease state involves JAK3.

14. The use according to claim 11, wherein the tyrosine kinase-disease state is selected from the group consisting of Atopy, such as Allergic Asthma, Atopic Dermatitis (Eczema), and Allergic Rhinitis; Cell Mediated Hypersensitivity, such as Allergic Contact Dermatitis and Hypersensitivity Pneumonitis; Rheumatic Diseases, such as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis, Juvenile Arthritis, Sjogren's Syndrome, Scleroderma, Polymyositis, Ankylosing Spondylitis, Psoriatic

Arthritis; Other autoimmune diseases such as Type I diabetes, autoimmune thyroid disorders, and Alzheimer's disease; Viral Diseases, such as Epstein Barr Virus (EBV), Hepatitis B, Hepatitis C, HJN, HTLV 1, Varicella-Zoster Virus (VZV), Human Papilloma Virus (HPV), Cancer, such as Leukaemia, Lymphoma and Prostate Cancer.

15. A method of suppressing the immune system of a subject, the method comprising administering a therapeutically effective amount of at least one compound of any one of claims 1 to 5 or a therapeutically effective amount of a pharmaceutical composition according to claim 6.

16. A method according to claim 15, wherein the suppressing of the immune system is for the treatment of a disease state selected from the group consisting of lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, asthma, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, and Alzheimer's disease.

17. A method according to claim 15, wherein the suppressing of the immune system is to modify the immune system response to a transplant into a subject.

18. A method according to claim 17, wherein the transplant is an organ transplant or a tissue transplant.

19. Use of a compound according to any one of claims 1 to 5 or a therapeutically effective amount of a pharmaceutical composition according to claim 6 in the preparation of a medicament for suppressing the immune system of a subject.

20. The use according to claim 19, wherein the suppressing of the immune system is for the treatment of a disease state selected from the group consisting of lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, Type I diabetes and complications from diabetes, cancer, asthma, atopic dermatitis, autoimmune thyroid disorders, ulcerative colitis, Crohn's disease, and Alzheimer's disease.

21. The use according to claim 19, wherein the suppressing of the immune system is to modify the immune system response to a transplant into a subject.

22. The use according to claim 21, wherein the transplant is an organ transplant or a tissue transplant.