Hydroxamic acids substituted by heterocycles useful for inhibition of tumor necrosis factor

1 Compounds of formula (I), wherein: n is 1 to 6; Het is a nitrogen containing ring fused to the benzene ring on two adjacent carbon atoms to form a bicyclic ring system which ring system may be optionally substituted; R 1 is hydrogen, C 1-8 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, aryl, heteroaryl, heterocyclyl, arylC 1-6 alkyl, heteroarylC 1-6 alkyl, heterocyclylC 1-6 alkyl or C 3-8 cycloalkylC 1-6 alkyl; R 2 is C 1-6 alkyl, C 2-6 alkenyl, arylC 1-6 alkyl, heteroarylC 1-6 alkyl or the side-chain of a naturally occurring amino acid; R 3 is hydrogen, C 1-6 alkyl, C 3-8 cycloalkyl, C 4-8 cycloalkenyl, arylC 1-6 alkyl, heteroarylC 1-6 alkyl or heterocyclylC 1-6 alkyl; R 4 is hydrogen or C 1-6 alkyl; or R 3 and R 4 together with the nitrogen atom to which they are joined form a heterocyclic ring; wherein any group or ring, in R 1 -R 4 , is optionally substituted; and pharmceutically acceptable salts and in vivo hydrolysable esters thereof, are described as inhibitors of the production of Tumour Necrosis Factor and/or one or more matrix metalloproteinase enzymes. Compositions containing them and their preparation are also described.