Hydroxamic acid derivatives as matrix metalloprotease (MMP) inhibitors

A process for the preparation of a compound of formula (I):

• or a pharmaceutically or veterinarily acceptable salt thereof, or a pharmaceutically or veterinarily acceptable solvate of either entity,
• wherein
• the broken line represents an optional bond;
• A is C or CH;
• B is CH2, O or absent;
• R1 and R2 are each independently selected from hydrogen, C1 to C6 alkyl optionally substituted with C1 to C4 alkoxy or phenyl, and C1 to C6 alkenyl;
• or, together with the carbon atom to which they are attached, form a C3 to C6 cycloalkyl group which optionally incorporates a heteroatom linkage selected from O, SO, SO2 and
• NR6 or which is optionally benzo-fused;
• R3 is hydrogen, halo, R7 or OR7;
• R4 is hydrogen, C1 to C4 alkyl, C1 to C4 alkoxy, trifluoromethyl or halo;
• R6 is hydrogen or C1 to C4 alkyl;
• R7 is a monocyclic or bicyclic ring system selected from phenyl, thienyl, furyl, pyridinyl, pyrimidinyl, naphthyl, indanyl, benzothienyl, benzofuranyl, 2,3-dihydrobenzofuranyl, indolyl, quinolinyl, isoquinolinyl, benzodioxolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl and benzodioxanyl, any of which ring systems is optionally substituted with one or two substituents selected from C1 to C4 alkyl optionally substituted with C1 to C4 alkoxy or hydroxy, C1-C4 alkoxy optionally substituted with C1 to C4 alkoxy or hydroxy, C1 to C4 alkylthio, trifluoromethyl, trifluoromethoxy, halo and cyano;
• m is 1 or 2;
• and
• n is 0, 1 or 2;
• with the proviso that B is not O when A is C;
• which comprises reacting a compound of formula (II):
• wherein R5 is hydrogen or C1 to C3 alkyl, and the broken line, A,B, R1, R2, R3, R4, m and n are as previously defined for formula (I), with hydroxylamine, optionally followed by formation of a pharmaceutically or veterinarily acceptable salt of the required product or a pharmaceutically or veterinarily acceptable solvate of either entity.