SYNTHESIS OF CARBOXYLIC AND HYDROXAMIC ACID DERIVATIVES

Abstract: A method for the preparation of carboxylic and hydroxamic acid derivatives by cocondensation in a liquid organic medium of three reaction components, namely a carboxylic acid reaction component of formula (II), an imine reaction component of formula (III), and an isonitrile reaction component of formula (IV), wherein X is hydrogen or an amino protecting group, or the residue of a solid phase reaction substrate; Y is (i) a group -CO2R5 wherein R5 is a carboxyl protecting group or the residue of a solid phase reaction substrate or (ii) a group -CONR6OR7 wherein R6 is an amino protecting group or the residue of a solid phase reaction substrate and R7 is a hydroxyl protecting group or the residue of a solid phase reaction substrate; [S1], [S2], [S3] and [S4] each represent covalently bound moieties which are substantially non reactive with the reaction components (II), (III), or (IV) defined above; provided that only one of X, R5, R6 and R7 is the residue of a solid phase reaction substrate.

Description: Synthesis of Carboxylic and Hydroxamic Acid Derivatives The present invention relates to a method for the preparation of hydroxamic acid and carboxylic acid derivatives, particularly biologically active compounds, and especially matrix metalloproteinase inhibitors Background to the Invention Biologicall y Active Hydroxamic Acid and Carboxylic Acid Derivatives Compounds which have the property of inhibiting the action of metalloproteiπases involved in connective tissue breakdown such as collagenase stromeiysin and gelatmase (known as "matrix metalloproteinases", and herein referred to as MMPs) are thought to be potentially useful for the treatment or prophylaxis of conditions involving such tissue breakdown, for example rheumatoid arthritis, osteoarthπtis, osteopenias such as osteoporosis, peπodontitis, gingivitis, comeal epidermal or gastric ulceration, and tumour metastasis, invasion and growth It has been found that hydroxamic acid MMP inhibitors can also inhibit the production of the cytokme tumour necrosis factor (herein referred to as "TNF") (Mohler et al Nature 1994 370 218-220, Gearing AJH et al , Nature 1994, 370 555-557, McGeehan GM et al Nature 1994 370, 558-561 ) Compounds which inhibit the production or action of TNF are thought to be potentially useful for the treatment or prophylaxis of many inflammatory, infectious, immunologicai or malignant diseases These include, but are not restricted to, septic shock, haemodynamic shock and sepsis syndrome post ischaemic reperfusion injury, malaria, Crohn's disease, mycobacterial infection, meningitis, psoriasis congestive heart failure, fibrotic disease, cachexia graft rejection, cancer, autoimmune disease, rheumatoid arthritis, multiple sclerosis, radiation damage, toxicity following administration of immunosuppressive monoclonal antibodies such as OKT3 or CAMPATH-1 and hyperoxic alveolar injury Since excessive TNF production has been noted in several diseases or conditions also characterised by MMP-mediated tissue degradation, compounds which inhibit both MMPs and TNF production may have particular advantages in the treatment or prophylaxis of diseases or conditions in which both mechanisms are involved. Metalloproteinases are characterised by the presence in the structure of a zinc(ll) ionic site. It is now known that there exists a range of metalloproteiπase enzymes that includes fibroblast collagenase (Type 1), PMN-collagenase, 72 kDa-gelatinase, 92 kDa-gelatinase, stromelysin, stromelysin-2 and PUMP-1 (J.F. Woessner, FASEB J, 1991 , 5, 2145-2154). Many known MMP inhibitors are peptide derivatives, based on naturally occuring amino acids, and are analogues of the cleavage site in the collagen molecule. A recent paper by Chapman et al. (J. Med. Chem., 1993, 36, 4293-4301 ) reports some general structure/activity findings in a series of N- carboxyalkyl peptides. Other known MMP inhibitors are less peptidic in structure, and may more properly be viewed as pseudopeptides or peptide mimetics. Such compounds usually have a functional group capable of binding to the zinc (II) site in the MMP, and known classes include those in which the zinc binding group is a hydroxamic acid, carboxylic acid, sulphydryl, and oxygenated phosphorus (eg phosphinic acid and phosphonamidate including aminophosphonic acid) groups. Two known classes of pseudopeptide or peptide mimetic MMP inhibitors have a hydroxamic acid group and a carboxylic group respectively as their zinc binding groups. With a few exceptions, such known MMPs may be represented by the structural formula (A) in which Z is the zinc binding hydroxamic acid (-CONHOH) or carboxylic acid (-COOH) group and the groups R, to R 4 are variable in accordance with the specific prior art disclosures of such compounds. Examples of patent publications disclosing such structures are given below. The following patent publications disclose pseudopeptide hydroxamic acid-based MMP inhibitors: US 4599361 (Searle) EP-A-0236872 (Roche) EP-A-0274453 (Bellon) WO 90/05716 (British Bio-technology) WO 90/05719 (British Bio-technology) WO 91/02716 (British Bio-technology) EP-A-0489577 (Celltech) EP-A-0489579 (Celltech) EP-A-0497192 (Roche) WO 92/13831 (British Bio-technology) WO 92/22523 (Research Corporation Technologies) WO 93/09090 (Yamanouchi) WO 93/09097 (Sankyo) WO 93/20047 (British Bio-technology) WO 93/24449 (Celltech) WO 93/24475 (Celltech) US 5256657 (Sterling Winthrop) EP-A-0574758 (Roche) WO 94/02446 (British Bio-technology) WO 94/02447 (British Bio-technology) WO 94/21612 (Otsuka) WO 94/25434 (Celltech) WO 94/25435 (Celltech) The following patent publications disclose pseudopeptide carboxylic acid-based MMP inhibitors: EP-A-0489577 (Celltech) EP-A-0489579 (Celltech) WO 93/24449 (Celltech) WO 93/24475 (Celltech) WO 94/25434 (Celltech) WO 94/25435 (Celltech) A key reaction, described in the above patent applications, for the synthesis of the pseudopeptide metalloproteinase inhibitors is the coupling of a carboxylic acid derivative of formula (B) with an amino acid derivative of formula (C) wherein is a protected hydroxamic acid group or a protected carboxylic acid group to give a compound of general formula (D): This compound (D) is then converted to a compound of general formula (A) by transformation of the group Z to a zinc binding group Z as defined for general formula (A). A disadvantage of this route is that the preparation of the amino acid derivative (C) usually involves a number of steps, particularly when it is an unnatural amino acid derivative, as is often desirable. There is therefore a need for alternative methods for the preparation of hydroxamic acid and carboxylic acid based compounds of type (A). Solid Phase Synthesis Solid phase synthesis is an established and effective method for the preparation of peptides, and offers advantages over conventional solution phase chemistry in terms of purification and simplicity (Atherton E, Sheppard RC, Solid Phase Peptide Synthesis: A Practical Approach; IRL Press at Oxford University Press: Oxford, 1989). Solid phase synthesis may also be used for the preparation of non-peptide molecules (Leznoff CC, Ace. Chem. Res. , 1978. 11 , 327-333) and recently there has been considerable interest in the application of this methodology to the synthesis of combinatorial libraries for biologically active lead compound optimisation and discovery (Moos WH et al., Annu. Rep. Med. Chem., 1993, 28. 315-324). Solid phase synthesis requires an appropriate solid substrate which carries a plurality of functional groups to which the first reactive entity in the proposed synthesis may be covalently coupled, and from which the desired molecule may be cleaved after assembly. The solid substrate should be compatible with the solvents and reaction conditions that are to be used in the peptide or non-peptide synthesis. The final step in solid phase synthesis is the cleavage of the covalent bond between the desired peptide or non-peptide molecule and the linker. It is desirable that the conditions for the cleavage are orthogonal to those used during the reactions employed for the synthesis of the peptide or non-peptide on the solid support such that undesired cleavage does not occur during the synthesis. Furthermore, the conditions for cleavage should be relatively mild such that they do not result in degradation of the desired peptide or non-peptide. Solid substrates which present hydroxyl groups as the points of attachment for the first stage of the synthesis are commonly used, for example substrates which present hydroxyl groups as derivatives of benzyl alcohol, the peptide or non-peptide being attached as a benzyl ester and cleaved by hydrolysis, acidolysis or aminolysis to release the peptide or non-peptide as a carboxylic acid, carboxylate ester or as a carboxamide Also used are substrates which present ammo groups, for example as derivatives of diphenylmethylamine, the peptide or non-peptide being attached as a carboxamide and cleaved by acidolysis to release the peptide or non-peptide as a carboxamide Substitution of such linkers by a nitro group can enable the photolytic cleavage of the peptides or non-peptides from the residue of the solid substrate Brief Description of the Invention It was the hypothesis of the present inventors that the Ugi reaction might provide an alternative route for the synthesis of pseudopeptide metalloproteinase inhibitors which could avoid the separate multi-step preparation of the ammo acid derivative (C) The Ugi reaction is a four component condensation reaction between a carboxylic acid, an amine, an aldehyde and an isonitnle that proceeds to give an am o acid amide derivative (I. Ugi, Angew Chem Int Ed Engl , 1982, 21 , 810- 819) The reaction has been used for the synthesis of peptides (M Waki and J Meienhofer, J Am Chem Soc , 1977, 99, 6075-6082, Ugi et al In Chemistry and Biochemistry of Ammo Acids, Peptides and Proteins, Vol 6 Marcel Dekker New York 1982, pp 245-289) but it has found particular application for the synthesis of β- lactam derivatives (K Kehagia et al , Tetrahedron, 1995, 51 , 139-144) The inventors contemplated that such a method might be conducted in solution or with one of the components attached to a solid phase support and could find application for the manufacture of compounds of structural type (A) and in the combinatorial synthesis of a library of compounds of structural type (A) The invention is based on the finding that compounds of type (D) which are protected precursors of compounds of structural type (A) may indeed be conveniently synthesised by application of Ugi reaction conditions, in solution or with one of the components attached to a solid phase support, for subsequent deprotection to provide the desired compounds of type (A) Detailed Description of the Invention The present invention provides a method for the preparation of a compound of formula (I) wherein X is hydrogen or an ammo protecting group, or the residue of a solid phase reaction substrate, Y is (i) a group -C0 2 R 5 wherein R 5 is a carboxyl protecting group or the residue of a solid phase reaction substrate or (u) a group -CONR 6 OR 7 wherein R 6 is an ammo protecting group or the residue of a solid phase reaction substrate and R- is a hydroxyl protecting group or the residue of a solid phase reaction substrate, and [S,], [S 2 ], [S 3 ] and [S 4 ] each represent covalently bound moieties which are substantially non reactive with the reaction components (II), (III), or (IV) defined below, provided that only one of X, R 5 R 6 and R 7 is the residue of a solid phase reaction substrate which method comprises causing the co-condensation in a liquid organic medium of three reaction components, namely a carboxylic acid reaction component of formula (ID, and an imine reaction component of formula (III), and an isonitπle reaction component of formula (IV), !N- -[S 4 ] (IV) wherein X, Y, [S,], [S 2 ], [S 3 ] and [S 4 ] are as defined with respect to formula (I) As used herein the term "ammo protecting group" means a group which may be used for the protection, i e temporary blocking, of ammo nitrogen functionality Such groups are widely known, for example from the art of peptide synthesis, and are discussed in the widely used handbook by T W Greene and P G M Wuts, Protective Groups in Organic Synthesis. 2nd Edition, Wiley, New York, 1991 Specific examples of ammo protecting groups include allyl and benzyl or benzyl optionally substituted in the phenyl ring by one or more nitro or methoxy substituents, for example 4-methoxybenzyl or 2,4-dιmethoxybenzyl As used herein the term "carboxylic acid protecting group" means a group which may be used for the protection, i e temporary blocking, of the oxygen functionality within a carboxylic acid Again such groups are widely known, for example from the art of peptide synthesis, and are discussed in the widely used handbook by T.W Greene and P G M Wuts, Protective Groups in Organic Synthesis, 2nd Edition, Wiley, New York, 1991. Specific examples of carboxyl protecting groups include allyl, t-butyl, and benzyl or benzyl optionally substituted in the phenyl ring by one or more πitro or methoxy substituents, for example 4-methoxybenzyl or 2,4- dimethoxybenzyl. As used herein the term "hydroxyl protecting group" means a group which may be used for the protection, i.e. temporary blocking, of the oxygen functionality of the hydroxyl group. Again such groups are widely known, for example from the art of peptide synthesis, and are discussed in the widely used handbook by T.W. Greene and P.G.M. Wuts, Protective Groups in Organic Synthesis, 2nd Edition. Wiley, New York. 1991. Specific examples of hydroxyl protecting groups include allyl. t-butyl, trimethylsilyl and benzyl or benzyl optionally substituted in the phenyl ring by one or more nitro or methoxy substituents, for example 4-methoxybenzyl or 2,4- dimethoxybeπzyl. In carrying out the above three-component co-condensation method of the invention, the imine reaction component (III) may be added to the reaction medium together with the carboxylic acid and isonitrile reaction components. It may also be pre¬ formed by the condensation of an aldehyde of formula (IIIA) and an amine of formula (IIIB): (IIIA) (IIIB) wherein X and [S 3 ] are as defined with respect to formula (I), and subsequently the carboxylic acid and isonitrile reaction components may be added without isolation of the pre-formed imine reaction component. Note: Compounds of formula (IIIB) have been referred to as "amines". Since X in formula (IIIB) may be hydrogen, the "amine" (IIIB) may be ammonia. As used herein in relation to compounds of formula (IIIB), the term "amine" includes ammonia In a modification of the method of the invention, the imine reaction component (III) may be formed in situ by the condensation of an aldehyde of formula (IIIA) and an amine of formula (IIIB) as defined above In this case, the method of the invention comprises causing the co-condensation in a liquid organic medium of four reaction components, namely the carboxylic acid reaction component of formula (II) above, the aldehyde reaction component of formula (IIIA) above, the amine reaction component of formula (IIIB) above, and the isonitrile reaction component of formula (IV) above, moieties [S,], [S 2 ], [S 3 ] and [S 4 ] being substantially non reactive with these reaction components The three- or four-component co-condensation method of the invention may be conducted in a protic solvent such as methanol or 2,2,2-trιfluoroethanol, in an aprotic solvent (e g. tetrahydrofuran, chloroform, methylene chloride or acetonitnle) or in a mixed protic/aprotic solvent system Methanol is the presently preferred reaction medium, but selection of appropriate organic liquid media for specific combinations of reaction components is a matter of routine The reaction components are added to the chosen liquid reaction medium and caused to co-react In the case where the imine is preformed, the subsequent co-condensation of carboxylic acid, imine and isonitrile components may proceed in higher yield if conducted in an aprotic solvent (e g tetrahydrofuran) in the presence of a Lewis acid catalyst (e g zιnc(ll) chloride) The moieties [S,], [S 2 ], [S 3 ] and [S 4 ] in the reaction components are, of course, dictated by the structure of the desired end product of the method of the invention To minimise unwanted by-products in their respective reaction components these moieties should not contain functional substituents which react substantially with the cognate reaction components In the three- and four-component methods of the invention, the co-condensation may be carried out with all reaction components in solution in the organic liquid medium, or with the carboxylic acid component (II) covalently bound to the residue of a solid phase reaction substrate, and the remaining components in solution, or with the imine component (III) covalently bound to the residue of a solid phase reaction substrate, and the remaining components in solution, or with the ammo group of component (IIIB) covalently bound to the residue of a solid phase reaction substrate, and the remaining components in solution The term "residue of a solid substrate" as used in the definition of groups X and Y of compound (I) or reaction components (II), (III) and (IIIB) refers to a solid base substrate which is substantially insoluble in aqueous or organic reaction media and which is directly, or indirectly through suitable linker groups linked to the relevant N or O atom by a covalent bond which is cleavable by acid hydrolysis or by photolysis Base substrates include those known in the art of solid phase peptide synthesis (see for example those described in Stewart JM and Young JD, Solid Phase Peptide Synthesis, 2nd Ed Pierce Chemical Company Rockford Illinois 1984) They include inorganic substrates, for example kieselguhr silica gel and controlled pore glass and polymeric organic substrates for example polystyrene polypropylene polyethylene glycol polyacrylamide cellulose as well as composite inorganic/polymeric substrates such as polyacrylamide supported within a matrix of kieselguhr particles Known base substrates also include ammo and hydroxy functionalised solid substrates, iβ those which are chemically modified by introduction of ammo or hydroxyl groups, to serve as convenient points for further chemical manipulation Examples of particular ammo or hydroxy functionalised solid supports are hydroxymethyl polystyrene, benzhydrylamme polystyrene ("BHA Resin '), methyl benzhydrylamme polystyrene ("MBHA Resin '), polyethylene glycol polystyrene ("PEG-PS") poly(dιmethylacrylamιde)polystyrene composite ("Polyhipe"), polyacrylamide Kieselguhr composite ("Macrosorb") or functionalised controlled pore glass It is known from the art of solid phase peptide synthesis that hydroxyl- or am o- carrying linker groups can be introduced onto amino and hydroxy functionalised solid substrates, the linker group having characteristics which facilitate the cleavage of the desired synthesised molecule from the solid support. The hydroxyl or amino groups presented by the linker groups serve as points for attachment of the first reactive entity in the proposed synthesis. Thus, in case of a hydroxyl-carrying linker group, the first amino acid of the peptide to be constructed may be attached as an ester formed between the linker-presented hydroxyl group and the carboxyl group of the amino acid. In the case of amino-carrying linker groups, the first amino acid of the peptide to be constructed may be attached as a carboxamide formed between the linker-presented amino group and the carboxyl group of the amino acid. An example of a solid support resin presenting amino groups on linker groups attached to the base substrate is the resin 5-(4'-aminomethyl-3',5'-dimethoxyphenoxy)-(N-4- methylbenzhydryl)pentyramide-copoly(styrene-1 %-divinylbenzene) resin which has the structure wherein "P" represents the copolystyrene divinylbenzene polymer backbone. In the solid phase synthesis aspects of the present invention: the carboxylic reaction component (II) may, for example, be attached to hydroxy groups presented by a solid base substrate as a carboxylic ester, or to amino groups presented by a solid base substrate as a N- alkoxycarboxamide; or the imine reaction component (III) may, for example, be formed on the amino groups presented by a solid base substrate, by reaction of such amine groups with the aldehyde component (IIIA); or the amine reaction component (IIIB) may be a solid base substrate which presents amino groups. By analogy with the methods of solid phase peptide synthesis, in the foregoing options in which the carboxylic or imine reaction components, or the amino group of component (IIIB), are linked to the residue of a solid base substrate, the bond between the reaction component and the substrate should be cleavable. by acid hydrolysis or photolysis. In practice this is often achieved by using a substrate in which the hydroxy or amino groups forming the points of attachmem in components (II) or (III), or the amino group of component (IIIB), are presented by benzylic alcohol or benzylamiπe derived linker groups which in turn are covalently bound to a solid base substrate. Such linker groups may, for example, have formula (V): wherein Z 1 represents -OH, -NH 2 or -ONH 2 ; R 8 represents hydrogen, C C 6 alkyl, or phenyl optionally substituted by one or more substituents selected from C r C 6 alkyl, C r C 6 alkoxy, halogen, nitrile or N0 2 ; R 9 and R 10 independently represent hydrogen, C,-C 6 alkyl, C,-C 6 alkoxy, halogen, nitriie or N0 2 ; R„ represents a group -(X 1 ) q -Y 1 - wherein q is 0 or 1 , X 1 represents -C(=0)-, -CH 2 -, -CH 2 C(=0)-. -0(CH 2 ) n C(=0)-, -0(CH 2 ) n C(=0)-(A 1 )m-, or -O(CH 2 ) n C(=0)-(A 1 ) m -B 1 -, wherein n is an integer from 1 to 6, m is 0 or 1 , A 1 represents -0-CH(R 12 )-NH- wherein R, 2 is the side chain of a natural or unnatural alpha amino acid, B 1 represents a spacer group -NH(CH 2 ) P - wherein p is 0 or an integer from 1 to 6, and Y represents -0- or -NH-, the R-. free valency being satisfied by covalent bonding to the solid base substrate. Another class of linker groups has formula (VA): wherein Z 1 R 8 R 9 and R 10 are as defined in formula (V), R 8A is as defined for R e in formula (V), and R 11A is a bond or is as defined for R., in formula (V). The product of the method of the invention is a compound of formula (I) defined above. However that product (I) may be further treated, in one or several steps, before or after isolation from the reaction medium, to remove any amine protecting group X, or any amine protecting group, carboxyl protecting group or hydroxyl protecting group present in group Y (or indeed in moieties [S,], [S 2 ], [S 3 ] and [S 4 ]), and, in the case where one of X, R 5 , R 6 and R 7 is the residue of a solid phase reaction substrate, to cleave the covalent bond between that substrate and the relevant N atom of X or N or O atom of Y. Following such protecting group removal and any necessary cleavage from solid phase reaction substrate, the product has the structure (IA): wherein Z is a carboxylic acid group -COOH or a hydroxamic acid group -CONHOH, and R,-R 4 are either the same as [S,j - [S 4 ] or are the result of deprotection of one or more of [S,] - [S 4 ] As discussed above, under the heading "Background to the Invention" many members of the class of compounds represented by formula (IA) have valuable biological activities, particularly the ability to inhibit the activity of the matrix metalloprotemase enzymes The method of the invention therefore finds particular application in the synthesis of matrix metalloprotemase inhibitors having the general formula (IA), many examples of which are described in the patent and other publications listed earlier Removal of amine protecting groups, carboxyl protecting groups or hydroxyl protecting groups as referred to in the preceeding paragraph is a common procedure requiring little or no elaboration The art of peptide synthesis is a prolific source of detailed knowledge of these methods, as is the reference work cited earlier namely T W Greene and P G M Wuts, Protective Groups in Organic Synthesis, 2nd Edition Wiley, New York, 1991 The following Examples disclose the utility of the method of the invention for the preparation of biologically active hydroxamic acid derivatives The carboxylic acids produced as intermediates in Examples 1-4 and as the product in Example 6 are also biologically active The following abbreviations have been used throughout DCM Dichloromethane DMF N,N-Dimethylformamide EDC N-Ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride HOBt 1 -Hydroxybenzotriazole NMM N-Methylmorpholine TFA Trifluoroacetic acid TLC Thin layer chromatography Η and 13 C NMR spectra were recorded using a Bruker AC 250E spectrometer at 250.1 and 62.9 MHz, respectively. Example 1 3R-[2,2-Dimethyl-1S,R-(benzylcarbamoyi)propylcarbamoyl]-5-methylhexano- hydroxamic acid Step A t-Butyl 3R-[2,2-dimethyl-1 S,R-(benzylcarbamoyl)propyl(2,4-dimethoxybenzyl)- carbamoyl]-5-methylhexanoate Trimethylacetaldehyde (0.56 ml, 5.17 mmol) was added to a stirred solution of 2,4- dimethoxybenzylamine hydrochloride (0.86 g, 5.17 mmol) and triethylamme (0.72 ml, 5.17 mmol) in methanol (30 ml) at room temperature. To this solution was added benzyl isocyanide (0.97 ml, 5.17 mmol) followed by 2R-(2-methylpropyl)succinic acid-4-t-butyl ester (1.19 g, 5.17 mmol). The mixture was stirred for 2 h and concentrated under reduced pressure to give a pale yellow wax. The residue was taken up in DCM and washed with 1 M Na 2 C0 3 , 1 M HCI and brine, dried over anhydrous MgS0 4 , filtered and evaporated. Column chromatography (Silica gel; 2: 1 hexane/diethyl ether) gave the title compound (1.13 g, 38%) as a white foam. 1 H NMR (CDCI 3 ) δ 7.25 (6H, m), 7.00 (1 H, m), 6.42-6.25 (2H, m), 5.06-4.87 (2H, m), 4.63-4.32 (2H, m), 4.20 (Ϊ H, m), 3.82-3.65 (6H, br m), 3.10-2.41 (2H. br m), 2.28 (1 H, m), 1.48-1.18 (12H, br m), 1.12 (9H, s), 0.99-0.75 (2H, br m), 0.75-0.45 (4H, br m). Step B 3R-[2,2-Dimethyl-1 S,R-(benzylcarbamoyl)propylcarbamoyl]-5-methylhexanoic acid t-Butyl 3R-[2,2-dimethyl-1 S,R-(benzyicarbamoyl)propyl(2,4-dimethoxybenzyl)- carbamoyl]-5-methylhexanoate (0.90 g, 1.58 mmol) was taken up in a 1 :1 TFA/DCM mixture (10 ml) and placed overnight in a refridgerator. It was noted that the mixture had changed colour from clear to deep purple. The solution was concentrated under reduced pressure and azeotroped with toluene to yield crude 3R-[2,2-dimethyl-1 S.R- (benzylcarbamoyl)propylcarbamoyl]-5-methylhexanoic acid which was used directly in the next step. Η NMR (CDCI 3 ) δ 7.72 (1 H, m), 7.39-7.14 (5H, br m), 6.51 (1 H, m), 4.47-4.25 (1 H, br m), 4.07 (1 H, m), 3.83-3.66 (1 H, m), 2.72 (1 H, m), 2.54 (1 H, m), 2.38 (1 H. m), 1.65-1.40 (1 H, br m), 1.37-1.15 (1 H, br m), 1.05-0.80 (15H. br m). Step C O-Benzyl 3R-[2,2-dimethyl-1 S,R-(benzylcarbamoyl)propylcarbamoyl]-5- methylhexanohydroxamic acid 3R-[2,2-Dimethyl-1 S,R-(benzylcarbamoyl)propylcarbamoyl]-5-methylhexanoic acid (0.58 g, 1.54 mmol) was dissolved in dry DMF (7 ml) and treated with NMM (0.19 g, 1.85 mmol), HOBt (0.25 g, 1.85 mmol), EDC (0.35 g, 1.85 mmol) and O- benzylhydroxylamine (0.28 g, 2.31 mmol). The mixture was stirred overnight at room temperature and concentrated under reduced pressure. The residue was taken up in ethyl acetate and washed with water, 1 M Na 2 C0 3 , 1 M HCI and brine, dried over anhydrous MgS0 4 , filtered and evaporated. Column chromatography (Silica gel; 0-5% methanol in DCM) gave the title compound (0.29 g, 39%). Η NMR (CDCI 3 ) δ 8.95 (1 H, m), 7:45-7.10 (10H, br m), 7.00-6.68 (1 H, br m), 6.50-6.25 (1 H, br m), 5.01-4.75 (2H, br m), 4.50-3.95 (3H, br m), 2.94 (1H, m), 2.57-2.20 (2H, br m), 1.55 (2H, br m), 1.15 (1 H, m), 1.07-0.78 (15H, br m). Step D 3R-[2,2-Dimethyl-1 S,R-(benzylcarbamoyl)propylcarbamoyl]-5-methylhexano- hydroxamic acid A mixture of O-benzyl 3R-[2,2-dimethyl-1S,R-(benzylcarbamoyl)propylcarbamoyl]-5- methylhexanohydroxamic acid (0.25 g, 0.52 mmol) and 10% palladium on carbon (50 mg) in ethanol was stirred overnight at room temperature under an atmosphere of hydrogen. The mixture was filtered, concentrated under reduced pressure and the residue purified by column chromatography (Silica gel; 2-5% methanol in DCM) to give a 1 :1 mixture of diastereoisomers of the title compound (82 mg, 40%) as a white powder: mp 165.2-166.3°C; Η-NMR (CD 3 OD) δ 7.18 (5H, m), 4.13-4.38 (2H, br m), 4.05 (1 H, m), 2.87 (1 H, m), 2.40 (1 H, dd, J 8.0, 14.7 Hz), 2.14-2.28 (1 H, br m), 1.56-1.32 (2H, br m), 1.08 (1 H, m), 0.92 (4.5H, s), 0.88 (4.5H, s), and 0.72 - 0.85 (6H, br m); 3 C-NMR (CD 3 OD) δ 177.58, 177.19, 173.69, 173.60, 169.64, 169.40, 139.98, 139.89. 129.52, 128.75, 128.21 , 60.09, 59.25, 44.21 , 42.60. 42.44, 42.30, 40.22, 35.69, 35.26, 27.26, 27.10, 27.02, 23.74, 23.49, 22.63 and 22.22. Example 2 3R-[1 S , R-(Benzylcarbamoyl)-1-(1-methylcyclopropyl)methylcarbamoyl]-5- methylhexanohydroxamic acid Step A t-Butyl 3R-[1 S,R-(benzylcarbamoyl)-1-(1-methylcyclopropyl)methyl(2,4-dιmethoxy- benzyl)carbamoyl]-5-methylhexanoate 2,4-Dιmethoxybenzylamιne hydrochloride (1.68 g, 10.03 mmol) was dissolved in dry methanol containing activated 4A molecular sieves, triethylamme (1 4 ml, 10.03 mmol) and 1-methylcyclopropylaldehyde (1.2 ml, 10.94 mmol) and the mixture stirred in an ice bath for 0.5 h. To this solution was added benzyl isocyanide (1 2 ml. 10.03 mmol) followed by 2R-(2-methylpropyl)succιnιc acid-4-t-butyl ester (2.10 g, 9 12 mmol) The mixture was stirred overnight at room temperature, filtered and concentrated under reduced pressure The residue was taken up in ethyl acetate and washed with water 1 M Na 0 3 . 1 M HCI and brine, dried over anhydrous MgS0 4 , filtered and evaporated. Column chromatography (Silica gel, 0-5% methanol in DCM) gave the title compound (3.01 g, 59%) as a white foam 1 H NMR (CDCI 3 ) δ 7.25 (6H, m), 7 03 (1 H, m), 6.33 (1 H, m), 4 78-3 96 (5H, br m), 3 76 (6H, m), 3.07 (1 H, m), 2 45 (1 H, m), 2.28 (1 H, m), 1 64-1 18 (12H, br m), 1 03-0 67 (13H, br m). Step B 3R-[1 S,R-(Benzyicarbamoyl)-1-(1-methylcyclopropyl)methylcarbamoyl]-5- methylhexanoic acid t-Butyl 3R-[1 S,R-(benzylcarbamoyl)-1-(1-methylcyclopropyl)methyl(2,4-dιmethoxy- benzyl)carbamoyl]-5-methylhexanoate (3 01 g, 5 40 mmol) was taken up in DCM (50 ml) and TFA (2 1 ml, 27 0 mmol) added The mixture was left to stand at room temperature over the weekend The solution was concentrated under reduced pressure and azeotroped with toluene and the residue was purified by column chromatography (Silica gel, 2% methanol in DCM) to give the title compound (0 63 g, 31 %) 1 H NMR (CDCI 3 ) δ 7 55-7 03 (7H, br m), 4 48-4 21 (3H br m), 2 76 (1 H, m), 2 65 (1 H, m), 2 42 (1 H, m), 1 65-1 33 (2H, m), 1 19 (1 H, m), 0 99-0 76 (13H, m) Step C 3R-[1 S R-(Benzylcarbamoyl)-1-(1-methylcyclopropyl)methylcarbamoyl]-5- methylhexanohydroxamic acid 3R-[1S,R-(Benzylcarbamoyl)-1-(1-methylcyclopropyl)methylcarbamoyl]-5- methylhexanoic acid (0.55 g, 1 46 mmol) was dissolved in dry DMF (10 ml) and cooled in an ice bath The solution was treated with NMM (0 22 g, 2 19 mmol), HOBt (0 24 g, 1 75 mmol), EDC (0.33 g, 1 75 mmol) and hydroxylamme hydrochloride (0 15 g, 2 19 mmol) at 0°C and the mixture allowed to warm up to room temperature stirred overnight and concentrated under reduced pressure The residue was taken up in ethyl acetate and washed with water and 1 M Na 2 C0 3 , dried over anhydrous MgS0 4 , filtered and evaporated Column chromatography (acid washed silica gel methanol in DCM) gave the title compound (0 14 g, 25%) as a white solid mp 175-180°C, Η-NMR (CD 3 OD) δ 7 06 - 7 24 (5H, m) 4 38 - 4 05 (3H br m), 2 78 (1 H m) 2 21 (1 H, m), 2 05 (1 H, m) 1 77 (1 H, m) 1 55 -1 25 (3H br m), 1 12 - 0 96 (2H br m), and 0 89 - 0 71 (12H, m) ,3 C-NMR (CD 3 OD) δ 177 33 173 33, 173 64 170 54 139 84, 129 51 , 129 34, 128 62 128 21 127 94, 59 32, 58.65, 44 02, 42 52 42 16, 42 09, 38 29, 37 78 37 06, 27 23, 26 97 25 96, 23 63 22 42, 15 89, 15 16 11 82 and 11 19 Example 3 3R-[2,2-Dimethyl-1S,R-(t-butylcarbamoyl)propylcarbamoyl]-5-methylhexano- hydroxamic acid Step A t-Butyl 3R-[2,2-dimethyl-1S,R-(t-butylcarbamoyl)propyl-carbamoyl]-5- methylhexanoate Trimethylacetaldehyde (0.24 ml, 2.17 mmol) was added to a stirred 0.2M solution of ammonia in methanol (21.7 ml, 4.34 mmol) at room temperature After 10 mm, t- butyl isocyanide (0.25 ml, 2.17 mmol) was added followed by 2R-(2- methylpropyl)succinic acid-4-t-butyl ester (0.50 g, 2 17 mmol) The mixture was stirred overnight and concentrated under reduced pressure to give t-butyl 3R-[2,2- dιmethyl-1S,R-(t-butylcarbamoyl)propyl-carbamoyl]-5-methylhexanoate as an amorphous white solid (0.49 g, 57%). Η NMR (CDCI 3 ) δ 6.52 (1 H, d, J 9 Hz), 6.23 (1 H. d, J 12 Hz), 4.20 (1 H, dd, J 9.3, 6.2 Hz), 2.78-2.22 (3H, m), 1.72-1.50 (2H, m), 1.42 (4 5H, s), 1 41 (4.5H, s), 1.33 (4.5H, s), 1.32 (4.5H, s), 1.30-1.05 (1 H, m), 0.97 (4.5H, s), 0.96 (4.5H, s), 0 95-0.83 (6H, m). Step B 3R-[2.2-Dimethyl-1S.R-(t-butylcarbamoyl)propylcarbamoyl]-5-methylhexaπoιc acid A 1.1 TFA/DCM mixture (20 ml) was added to t-butyl 3R-[2,2-dimethyl-1S,R-(t- butylcarbamoyl)propyl-carbamoyl]-5-methylhexanoate (0.49 g, 1.23 mmol) and the resulting solution placed in a refridgerator for 48 h The solution was concentrated under reduced pressure and azeotroped with diethyl ether to yield crude 3R-[2,2- dιmethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]-5-methylhexanoιc acid which was used directly in the next step 1 H NMR (CDCI 3 ) δ 8 98 (1 H, br s), 8 11 (0 5H d J 9 Hz), 7 86 (0 5H, d, J 9 Hz), 6 41 (1 H, d, J 16 Hz), 4 31 (1 H, d, J 9 Hz), 3 03-2 35 (3H, m), 1 70-1 40 (3H, m), 1 35 (4 5H, s), 1 34 (4 5H, s), 0 98 (4 5H, s), 0 95 (4 5H s), 0 93-0 83 (6H, m) Step C O-Benzyl 3R-[2,2-dιmethyl-1 S R-(t-butylcarbamoyl)propylcarbamoyl]-5- methylhexanohydroxamic acid Crude 3R-[2,2-dιmethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]-5-methylhexanoιc acid from the previous step was dissolved in dry DMF (20 ml) cooled to 0°C and treated with HOBt (0 18 g, 1 36 mmol), EDC (0 29 g, 1 49 mmol) and O- benzylhydroxylamine (0 18 g, 1 49 mmol) The mixture was stirred overnight at room temperature and concentrated under reduced pressure The residue was taken up in DCM (30 ml) An insoluble solid formed which was removed by filtration and set aside The organics were washed with 1 M HCI, 1 M Na : C0 3 and brine dried over anhydrous MgS0 4 , filtered and evaporated The solid residue was combined with the previously isolated solid and crystallised from ethyl acetate (30 ml) to give O-benzyl 3R-[2,2-dιmethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]-5- methylhexanohydroxamic acid (0 27g, 49%) as a white solid Η NMR (CDCI 3 ) δ 7 35-7 20 (5H, m) 4 70 (2H, s), 4 13-3 98 (1 H, m), 2 95-2 73 (1 H, m) 2 28-1 95 (2H m), 1 53-1 33 (2H, m), 1 23 (9H s), 1 15-1 00 (1H, m), 0 93 (9H, s), 0 88-0 75 (6H, m) Step D 3R-[2 , 2-Dιmethyl-1S.R-(t-butylcarbamoyl)propylcarbamoyl]-5-methylhexano- hydroxamic acid A mixture of O-benzyl 3R-[2,2-dimethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]-5- methylhexanohydroxamic acid (0.27 g, 0.60 mmol) and 10% palladium on carbon (45 mg) in ethanol (30 ml) was stirred overnight at room temperature under an atmosphere of hydrogen. The mixture was filtered, concentrated under reduced pressure to give 3R-[2.2-dιmethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]-5- methylhexano-hydroxamic acid (193 mg, 91 %) as a 1 :1 mixture of diastereoisomers Off-white powder Η-NMR (CD 3 OD) δ 7 60 (0.5H, d, J 8.7 Hz), 7 52 (0.5H, d, J 9.2 Hz), 7.35 (1 H, d, J 16 7 Hz), 4.06 (1 H, dd, J 15.5, 9 1 Hz), 2.83 (1 H, m), 2.19 (1H, m), 2.05 (1 H, m), 1.56-1 31 (2H, br m), 1.22 (4.5H, s), 1.21 (4.5H, s), 1.16-1.02 (1 H, m), 0.90 (4.5H, s), 0.88 (4.5H, s), 0.88-0.73 (6H, br m); 13 C-NMR (CD 3 OD) δ 178.31 , 178.19, 173.14, 171.86, 64.11 , 63.53, 53.56, 43.92, 43.58, 43.52, 43 43, 38.55, 38.42, 36.70, 36.42, 30.30, 30.22, 28.76, 28.60, 28 48, 25.14, 25.06, 23.93, 23.55 Example 4 Synthesis of a combinatorial array of matrix metalloprotemase inhibitors The compounds of Example 4 as set out in Array 1 below were prepared following an analogous procedure to that employed above for the synthesis of the compound of Example 3 using the appropriate 2-(substιtuted)succιnιc acιd-4-t-butyl ester derivative in lieu of 2R-(2-methylpropyl)succιnic acιd-4-t-butyl ester, trimethylacetaldehyde and an isonitrile chosen from n-butyl isocyanide, isopropyl isocyanide, t-butyl isocyanide or cyclohexyl isocyanide. In the case of compounds 4s-4u O-tritylhydroxylamine was used in lieu of O-benzylhydroxylamine and the final hydroxamic acids were obtained by deprotection with 25% TFA in DCM. The desired hydroxamic acids were separated from the released triphenylmethane by flash separation on silica Array 1 : Compounds of Example 4 Note:- It was considered 1 jnnecessary to prepare ail corr .pounds in the array in order to obtain satisfactory diversity; the term "NA" indicates those compounds whose synthesis was not attempted. Data for the compounds of Example 4 are as follows (yields are given for over the four reaction steps):- Compound 4a: 3R-[2,2-dimethyl-1 S,R-(t-butyicarbamoyl)propylcarbamoyl]- butanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white powder (28%): Η-NMR (CD 3 OD) δ 7.43 (0.5H, s), 7.38 (0.5H, s), 4.06 (0.5H, s), 4.04 (0.5H, s), 2.90-2.76 (1 H, m), 2.37-2.20 (1H, m), 2.10-1.96 (1 H, m), 1.22 (9H, br s), 1.05 (1.5H, d J 7.1 Hz), 1.01 (1.5H, d, J 7.0Hz), 0.88 (9H, br s). v max /cm (KBr) 1639. Compound 4b: 3R-[2,2-dimethyl-1 S,R-(t-butylcarbamoyl)propyl-carbamoyl]- pentanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white powder (32%): Η-NMR (CD 3 OD) δ 4.09 (0.5H, s), 4.02 (0.5H, s), 2.74- 2.60 (1 H, m), 2.32-2.19 (1 H, m), 2.17-2.01 (1 H, m), 1.60-1.30 (2H, m), 1.23 (4.5H, s), 1.21 (4.5H, s), 0.90 (4.5H, s), 0.89 (4.5H, s), 0.82 (1.5H, t, J 7.3 Hz), 0.77 (1.5H, t, J 7.4 Hz). v max /cm (KBr) 1637. Compound 4c: 3R-[2,2-dimethyl-1 S,R-(t-butyicarbamoyl)propyicarbamoyl]- heptanohydroxamic acid (1 :1 mixture of diastereoisomers) White powder (36%): 'H-NMR (CD 3 OD) δ 7.39 (0.5H, s), 7.32 (0.5H, s), 4.08 (0.5H. s), 4.02 (0.5H, s), 2.80-2.70 (1 H, m), 2.32-2.19 (1 H, m), 2.18-2.00 (1 H, m), 1.60- 1.04 (6H, m), 1.22 (4.5H, s), 1.21 (4.5H, s), 0.90 (4.5H, s), 0.87 (4.5H, s), 0.85-0.76 (3H, m). v cm (KBr) 1637. Compound 4d: 3R-[2,2-dimethyl-1 S,R-(n-butylcarbamoyl)propylcarbamoyl]- nonanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white solid (9%):1 H-NMR (CD 3 OD) δ 4.13-3.98 (1 H, m), 2.78-2.67 (2H, m). 2.12-2.02 (1 H, m), 2.38-2.20 (2H, m), 1.44-1.1 1 (14H, br m), 0.92 (4.5H, s), 0.89 (4.5H, s), 0.85-0.77 (6H, m). Compound 4e: 3R-[2,2-dimethyl-1 S,R-(i-propylcarbamoyl)propylcarbamoyl]- nonanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white solid (22%): Η-NMR (CD 3 OD) δ 4.06 (0.5H, s), 4.14 (0.5H, s), 3.92-3.79 (1 H, m), 2.80-2.62 (1 H, m), 2.32-2.19 (1 H, m), 2.15-2.01 (1 H, m), 1.50-1.14 (10H, br m), 1.06-1.01 (6H, m), 0.91 (4.5H, s), 0.88 (4.5H, s), 0.83-0.75 (3H, m). Compound 4f: 3R-[2,2-dimethyl-1 S,R-(t-butylcarbamoyl)propylcarbamoyl]- nonanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white solid (12%):Η-NMR (CD 3 OD) δ 4.09 (0.5H, s), 4.02 (0.5H, s), 2.75-2.69 (1 H, m), 2.29-2.19 (1 H, m), 2.11-2.02 (1 H, m), 1.57-1.30 (2H, br m), 1.23 (4.5H, s), 1.22 (4.5H, s), 1.18-1.16 (8H, m), 0.90 (4.5H, s), 0.89 (4.5H, s), 0.80-0.74 (3H, m). Compound 4g: 3R-[2.2-dimethyl-1 S.R-(cyclohexylcarbamoyl)propylcarbamoyl]- nonanohydroxamic acid (1 : 1 mixture of diastereoisomers) White solid (28%); Η-NMR (CD,OD) δ 4.13-4.06 (0.5H, m), 4.19-4.15 (0.5H, m), 3.54-3.49 (1 H, m), 2.76-2.71 (1 H, m), 2.12-2.00 (1 H, m), 2.31-2.19 (1 H, m), 1 .80- 1 .40 (21-1, br. m), 1.32-1 .04 (18H, m), 0.90 (4.5H, s), 0.88 (4.5H, s), 0.86-0.77 (3H, m). Compound 4h: 3R-[2.2-dimethyl-1 S,R-(n-butylcarbamoyl)propyicarbamoyl]- decanohydroxamic acid (1 : 1 mixture of diastereoisomers) Colourless oil (8%): Η-NMR (CD 3 OD) δ 4.07 (0.5H, s), 4.14 (0.5H, s), 2.79-2.67 (2H. m), 2.34-2.18 (2H, br m), 2.11-2.05 (1 H, m), 1 47-1 16 (16H, br m), 0 93-0 89 (9H, m), 0 84-0 75 (6H. m) Compound 4ι 3R-[2.2-dιmethyl-1 S,R-(ι-propylcarbamoyl)propylcarbamoyl]- decanohydroxamic acid (1 1 mixture of diastereoisomers) Yellow - brown solid (41%) Η-NMR (CD 3 OD) δ 4 19-4 06 (1 H, m), 3 93-3 81 (1 H, m), 2 82-2.69 (1 H, m), 2.38-2 02 (2H, br m), 1 59-1.00 (18H, br m), 0 91 (4 5H, s), 0 88 (4 5H, s), 0 86-0 75 (3H, m) Compound 4j 3R-[2.2-dιmethyl-1 S R-(t-butylcarbamoyl)propylcarbamoyl]- decanohydroxamic acid (1 1 mixture of diastereoisomers) White solid (27%) Η-NMR (CD 3 OD) δ 4 12-4 09 (0 5H m), 4 06-4 03 (0 5H, m), 2 79-2.68 (1 H, m), 2.29-2.19 (1 H, m), 2.12-2 03 (1 H, m), 1 55-1 37 (2H, m), 1.22 (9H, s), 1 18-1 11 (10H, m), 0.90 (4 5H, s), 0 88 (4 5H, s), 0 79-0 75 (3H, m) Compound 4k 3R-[2.2-dιmethyl-1 S,R-(cyclohexylcarbamoyi)propylcarbamoyϊ]- decanohydroxamic acid (1 1 mixture of diastereoisomers) Off-white solid (38%) 'H-NMR (CD 3 OD) δ 4 22-4 18 (1 H m) 3 62-3 46 (1 H m), 2 82-2.66 (1 H, m), 2 53-2 00 (2H, br m), 1 80-1 40 (2H, br m), 1 32-1 12 (20H, br m), 0 92 (4 5H, s), 0 84 (4 5H, s), 0 58 (3H, m) Compound 41 3R-[2 2-dιmethyl-1 S,R-(n-butyicarbamoyl)propylcarbamoyl]- undecanohydroxamic acid (1 1 mixture of diastereoisomers) Pale yellow solid (42%) Η-NMR (CD 3 OD) δ 4 10-4 07 (0 5H, m), 4 21-4 15 (0 5H m), 3 10-3 01 (2H, m), 2 80-2 71 (1 H, m), 2 32-1 88 (2H, br m), 1 69-1 17 (18H, br m), 0 92 (3H, s), 0 88 (6H, s), 0 86-0 76 (6H, m) Compound 4m: 3R-[2,2-dimethyl-1S,R-(i-propylcarbamoyl)ρropylcarbamoyl]- undecanohydroxamic acid (3:2 mixture of diastereoisomers) Yellow solid (45%): Η-NMR (CD 3 OD) δ 4.22-3.99 (1 H, m), 4.92-3.79 (1 H, m), 2.80- 2.64 (1 H, m), 2.35-2.16 (1 H, br m), 2.10-1.91 (1 H, br m), 1.55-1.40 (2H, m), 1.26- 1.00 (18H, br m), 0.93 (3H, s), 0.88 (6H, s), 0.75-0.83 (3H, m). Compound 4n: SR-β^-dimethyl-IS^-ft-butylcarbamoy propylcarbamoyl]- undecanohydroxamic acid (3:2 mixture of diastereoisomers) Pale yellow solid (10%): Η-NMR (CD 3 OD) δ 4.12-3.97 (1H, m), 2.80-2.71 (1H, m), 2.30-2.13 (1H, m). 2.11-2.00 (1 H, m), 1.51-1.47 (2H, m), 1.22 (4.5H, s), 1.20 (4.5H, s), 1.17-1.13 (12H, m), 0.90-0.88 (9H, m), 0.86-0.75 (3H. m). Compound 4o: 3R-[2,2-dimethyl-1S,R-(cyclohexylcarbamoyl)proρylcarbamoyl]- undecanohydroxamic acid (1 :1 mixture of diastereoisomers) Pale yellow solid (43%): Η-NMR (CD 3 OD) ό 4.16-4.12 (0.5H, m). 4.06 (0.5H, m), 3.54-3.49 (1 H. m). 2.78-2.71 (1 H. m), 2.30-2.19 (1 H. br m). 2.16-1.97 (1 H, br m), 1.78-1.50 (2H. br m). 1.24-1.04 (22H, m), 0.91 (4.5H. s), 0.88 (4.5H. s), 0.86-0.76 (3H, m). Compound 4p: 3R-[2.2-dimethyl-1 S,R-(t-butylcarbamoyl)-propyl-carbamoyl]-4- phenylbutanohydroxamic acid (2:1 mixture of diastereoisomers) Off-white powder (36%): 'H-NMR (CD 3 OD) δ 7.20-7.00 (5H, m), 4.01 (0.66H, s), 3.82 (0.33H, s), 3.16-3.00 (1 H, m), 2.90-2.53 (2H. m). 2.38-2.02 (2H, m), 1.21 (3H, s), 1.17 (6H, s), 0.84 (6H. s), 0.63 (3H, s); v cm (KBr) 1635. Compound 4q: 3R-[2.2-dimethyl-1 S,R-(n-butylcarbamoyl)-propyl-carbamoyl]-4-thien- 3-ylbutanohydroxamic acid (4:1 mixture of diastereoisomers) Brown wax (8%): Η-NMR (CD 3 OD-CDCI 3 ) δ 7.52-6.82 (~7H, m), 4.34 and 4.13 (1 H, dd), 3.33-3.12 (4H, m). 2.93-2.48 (3H, m), 1.52-1.32 (4H, m), 1.28 and 1.22 (~9H, s), 0.91 (3H, t). Compound 4r: 3R-[2,2-dimethyl-1S,R-(t-butylcarbamoyl)-propyl-carbamoyl]-4-(3,4- methylenedioxyphenyl)butanohydroxamic acid (3:2 mixture of diastereoisomers) Light brown flakes (34%): Η-NMR (CD 3 OD) δ 6.72-6.45 (3H, m), 5.92 (1 H, s), 5.85 (1 H, m), 4.12-4.20 (1 H, m), 3.33-2.32 (5H, m), 1.35 (6H, s), 1.32 (3H, s), 1.21 (6H, s), 0.96 (3H, s); v max /cm (KBr) 1640. Compound 4s: 3R-[2,2-dimethyl-1 S,R-(n-butylcarbamoyl)propylcarbamoyl]-5-methyl- 2S-propen-2-yl-hexanohydroxamic acid (1 :1 mixture of diastereoisomers) Off-white amorphous solid (31 %): Η-NMR (CDCI 3 -CD 3 OD) δ 5.72 (1 H, m), 5.12 (2H, m), 4.41 (1 H, m), 4.01 (2H, m), 3.55 (1 H, m), 3.43-3.14 (3H, m), 3.02-2.52 (3H, m), 1.78-1.32 (7H, m), 1.28 and 1.22 (9H, m), 0.92 (3H, m), 0.82 (6H, m). Compound 4t: 3R-[2,2-dimethyl-1 S,R-(i-propylcarbamoyl)propylcarbamoyl]-5-methyl- 2S-propen-2-yl-hexanohydroxamic acid (2:1 mixture of diastereoisomers) Off-white amorphous solid (51 %): Η-NMR (CDCI 3 -CD 3 OD) δ 5.72 (1 H, m), 5.27- 4.98 (2H, m), 4.48 (1 H, m), 4.07 (1 H, heptet), 3.33-3.12 (2H, m), 2.83-2.48 (2H, m), 1.62-1.51 (1 H, m), 1.33 and 1.28 (9H, 2s), 1.33 (2H, m), 1.08-0.82 (12H, m). Compound 4u: 3R-[2,2-dimethyl-1 S,R-(cyclohexylcarbamoyl)propylcarbamoyl]-5- methyl-2S-propen-2-yl-hexanohydroxamic acid (3:1 mixture of diastereoisomers) Light brown amorphous solid (42%): H-NMR (CD 3 OD) δ 5.62 (1 H, m), 5.24-5.03 (2H, m), 4.45 (1 H, m), 3.74 (1 H, m), 3.21 (1 H, m), 2.80-2.24 (3H,m), 1.94-1.51 (6H, m), 1.43 and 1.24 (-10H, 2s), 1.48-1.22 (4H, m), 1.02 (6H, m), 0.91 (6H, m). Compound 4v: 3R-[2,2-dimethyl-1 S,R-(n-butylcarbamoyl)propylcarbamoyl]- nonadecanohydroxamic acid (3:1 mixture of diastereoisomers) Light brown glass (21 %): Η-NMR (CD 3 OD-CDCI 3 ) δ 7.21 (2H, m), 4.30-4.11 (1 H, m), 3.55 (2H, m), 3.25-3.1 (2H, m), 2.72-2.22 (2H, m), 1.62-1.45 (2H, m), 1.32-1.12 (~39H, br m), 0.85 (3H, t), 0.72 (3H, t). Compound 4x: 3R-[2,2-dimethyl-1 S,R-(cyclohexylcarbamoyl)propylcarbamoyl]- nonadecanohydroxamic acid (3:2 mixture of diastereoisomers) Off-white needles (23%): Η-NMR (CD 3 OD) δ 6.61 (1 H, br m), 4.7-4.6 (1 H, br m), 4.22-4.10 (1 H, m), 3.72-3.61 (2H, m), 2.82-2.61 (2H, m), 2.41 (1 H, m), 1.93-1.55 (5H, m), 1.38-1.21 (-41 H, br s), 1.02 (4H, m), 0.82 (3H, t); v max /cm (KBr) 1638. Example 5 2S-Hydroxy-3R-(1SR-[tert-butylcarbamoyl]-2,2-dimethyl-propylcarbamoyl)-5-methyl- hexanohydroxamic acid Step A N α -[2R-(2,2-Dimethyl-4-oxo-1 ,3-dioxalan-5S-yl)-4-methylpentanoyl]-D,L-tert-leucine- N-tert-butylamide Trimethylacetaldehyde (0.12 ml, 1.10 mmol) was added to a stirred 0.2M solution of ammonia in methanol (5.5 ml, 1.10 mmol) at room temperature under argon. After 1 h, t-butyl isocyanide (0.12 ml, 1.10 mmol) was added followed by 2R-(2,2-dimethyl- 4-0X0-1 , 3-dioxalan-5S-yl)-4-methylpentanoic acid (prepared as described in patent application WO 94/02446) (0.31 g, 1.10 mmol). The mixture was stirred for 48 h and concentrated under reduced pressure. The residue was taken up in ethyl acetate, washed with 1 M aqueous sodium bicarbonate, 1 M hydrochloric acid and brine, dried over anhydrous magnesium sulphate, filtered and evaporated under reduced pressure to give N"-[2R-(2,2-dimethyl-4-oxo-1 ,3-dioxalan-5S-yl)-4-methylpentanoyl]- D,L-tert-leucine-N-tert-butylamide (1 :1 mixture of diastereoisomers) as a white solid (0.30 g, 77%). 1 H NMR (CDCI 3 ) δ 6.61 (0.5H, br s), 6.58 (0.5H, br s), 6.22 (0.5H, br s), 6.09 (0.5H, br s), 4.43 (0.5H, d, J 6.7 Hz), 4.41 (0.5H, d, J 6.7 Hz), 4.24 (0.5H, d, J 9.0 Hz), 4.17 (0.5H. d, J 9.3 Hz), 2.70 (1 H, m), 1.80-1.20 (3H, m), 1.61 (1.5H, s), 1.59 (1.5H, s), 1.51 (1.5H, s), 1.49 (1.5H, s), 1.33 (4.5H, s), 1.32 (4.5H. s), 0.98 (9H, s), 0.96-0.88 (6H, m). Step B 2S-Hydroxy-3R-(1SR-[tert-butylcarbamoyl]-2,2-dimethyl-propylcarbamoyl)-5-methyl- hexanohydroxamic acid Sodium methoxide (0.12 g, 2.24 mmol) was added to a stirred solution of hydroxylamine hydrochloride (0.16 g, 2.24 mmol) in methanol (10 ml) at room temperature. After 2 h the mixture was filtered, the filtrate cooled in an ice bath and added to a cooled solution of N α -[2R-(2,2-dimethyl-4-oxo-1 ,3-dioxalan-5S-yl)-4- methylpentanoyl]-D.L-tert-leucine-N-tert-butylamide (0.20, 0.56 mmol) in methanol (2 ml). The mixture was allowed to warm to room temperature and stirred over night. The solvent was removed under reduced pressure and the residue triturated with diethyl ether (20 ml) to give 2S-hydroxy-3R-(1 SR-[tert-butylcarbamoyi]-2,2-dimethyl- propylcarbamoyl)-5-methyl-hexanohyroxamic acid (0.102 g, 48%) (1 :1 mixture of diastereoisomers) as a white powder. H-NMR (CD 3 OD) δ 8.32 (1H, s), 4.10 (0.5H, s), 4.02 (0.5H, s), 3.93 (0.5H, d, J 6.4 Hz), 3.90 (0.5H, d, J 7.2 Hz), 2.75 (1 H, m), 1.61-1.33 (2H, br m). 1.22 (4.5H, s), 1.21 (4.5H, s), 1.07 (1 H, m), 0.91 (4.5H, s), 0.89 (4.5H, s), 0.79 (6H, m). Example 6 3R-[S,R-(t-Butylcarbamoyl-4-methylphenylmethyl)carbamoyl]-5 methylhexanoic acid (3:2 mixture of diastereomers) A solution (5 ml) of 25% pipehdine in DMF was added to fluorenylmethyl oxycarbonyl-PAL-polystyrene (140 mg, 3 mmol/g loading, 0.042mmol) and the resin gently agitated in the solution for 30 minutes. The resin was then drained and washed successively with DMF, DCM, 1 :1 DCM and methanol (3 cycles), DCM and finally with diethyl ether. After drying in vacuo for 3 h at room temperature a solution of tolualdehyde in trimethylorthoformate (5 ml of a 1M solution) was added and the resulting resin suspension was mixed together for 3 h. The solution was drained from the resin as above and the resin washed thoroughly with DCM The resin was then swelled in DCM (1.5 ml) and tolualdehyde (49 μL, 0.42mmol) added. After 1 h 2R-ιsobutylsuccιnic acid-4-t-butyl ester (64 mg, 0.21 mmol) in methanol (1 ml) and t- butylisonitπle (32 μL, 0.21 mmol) were added and the whole mixture agitated together for three days. The solvents were then removed and the resin washed and dried as above. The resin was then reswelled in DCM (0.5 ml) and TFA (2 ml) and triethylsilane (100 μL) were added. After 2 h the TFA solution was collected and the resin washed with a further portion (2 ml) of TFA. The combined TFA extracts were evaporated to leave crude 3R-[S,R-(t-butylcarbamoyl-4-methylphenylmethyl)- carbamoyl]-5 methylhexanoic acid (3:2 mixture of diastereomers) as a pale solid (11 mg). Η NMR (CDCI 3 ) δ 7.95 and 7.7 (~2H, m), 7.73-7.08 (~4H, m), 6.32-6.21 (1H, m), 5.17-5.05 (1 H, m), 2.89-2.44 (3H, m), 2.39 and 2.32 (3H, 2s), 1.55-1.48 (3H, m), 1.33 and 1.23 (9H, 2s). 1.02-0.82 (6H, m).

Claims: Claims: 1. A method for the preparation of a compound of formula (I) wherein X is hydrogen or an amino protecting group, or the residue of a solid phase reaction substrate, Y is (i) a group -C0 2 R 5 wherein R 5 is a carboxyl protecting group or the residue of a solid phase reaction substrate or (ii) a group -CONR s OR, wherein R 6 is an amino protecting group or the residue of a solid phase reaction substrate and R 7 is a hydroxyl protecting group or the residue of a solid phase reaction substrate, and [Si], [S 2 ], [S 3 ] and [S 4 ] each represent covalently bound moieties which are substantially non reactive with the reaction components (II), (III), or (IV) defined below, provided that only one of X, R 5 , R 6 and R 7 is the residue of a solid phase reaction substrate, which method comprises causing the co-condensation in a liquid organic medium of three reaction components, namely a carboxylic acid reaction component of formula (ID, and an imine reaction component of formula (III), and an isonitrile reaction component of formula (IV), C=N [S 4 ] (IV) wherein X, Y, [S,], [S 2 ], [S 3 ] and [S 4 ] are as defined with respect to formula (I) 2 A method as claimed in claim 1 wherein the imine reaction component (III) is added to the reaction medium together with the carboxylic acid and isonitrile reaction components 3 A method as claimed in claim 1 wherein the imine reaction component (III) is pre-formed in the reaction medium by the condensation of an aldehyde of formula (IIIA) and an amine of formula (IIIB) [S 3 ] . - H "C ■ NH- (IIIA) (IIIB) wherein X and [S 3 ] are as defined with respect to formula (I), and subsequently the carboxylic acid and isonitrile reaction components are added without isolation of the pre-formed imine reaction component 4 A method as claimed in claim 1 wherein the imine reaction component is formed in situ during co-condensation in the medium of the carboxylic acid reaction component of formula (II) as defined in claim 1 , the aldehyde reaction component of formula (IIIA) as defined in claim 3, the amine reaction component of formula (IIIB) as defined in claim 3, and the isonitrile reaction component of formula (IV) as defined in claim 1 5 A method as claimed in any of the preceding claims wherein none of X, R 5 , R 6 , and R 7 is the residue of a solid phase reaction substrate, and the reaction of components (II), (III) and (IV), or (II), (IIIA), (IIIB) and (IV) as the case may be occurs with all such components in solution in the liquid organic medium 6 A method as claimed in any of claims 1 to 4 wherein one of X, R 5 , R 6 , and R 7 is the residue of a solid phase reaction substrate and the reaction of components (II), (III) and (IV) or (II), (IIIA), (IIIB) and (IV) as the case may be occurs with all the components in solution in the liquid organic medium except that containing the said residue of a solid phase reaction substrate 7 A method for the preparation of a compound of formula (IA) wherein Z is a carboxylic acid group -COOH or a hydroxamic acid group -CONHOH, and R,-R 4 are the same as [S.] - [S 4 ] as defined in connection with formula (I) in claim 1 which process comprises preparing a compound of formula (I) by a process as claimed in any of the preceding claims, and performing the additional step(s) of (i) removing any amino protecting group X from the compound of formula (I), removing any amino- or carboxyl- protecting group from Y in the compound of formula (I), and cleaving any bond between the compound of formula (I) and the residue of a solid phase reaction substrate.

Inventors: FLOYD CHRISTOPHER DAVID, WHITTAKER MARK, FLOYD, CHRISTOPHER, DAVID, WHITTAKER, MARK
Applicants: BRITISH BIOTECH PHARM, FLOYD CHRISTOPHER DAVID, WHITTAKER MARK, BRITISH BIOTECH PHARMACEUTICALS LIMITED, FLOYD, CHRISTOPHER, DAVID, WHITTAKER, MARK
Application year: 1996
Main classification: C07C259
IPC codes: C07C231, C07C237, C07C259