Cephalosporins, processes for their preparation and pharmaceutical compositions containing them.

摘要

Cephalosporin derivatives having a 3-position substituent of the formula I are described: <CHEM> wherein R<1> is hydrogen, alkenyl or optionally substituted alkyl, Het is a 5- or 6-membered heterocyclic ring bonded via a carbon atom to the amide linkage, wherein Het is selected from a group of the formulae II - III: <CHEM> wherein A is CH or a nitrogen atom; B is oxygen, sulphur or a group NR<4>; one or two of D, E, F and G are nitrogen atoms and the remainder are CH groups: or Het is a pyrazinone, pyridinone, pyridazinone or pyrimidinone ring, or is a thione equivalent of such a ring, said rings having a substituent R<4> on one nitrogen atom, or is pyranone, or pyranthione; the ring Het being fused by any two adjacent carbon atoms to the benzene ring; and Het being attached to the -CH2NR<1>CO- group via a carbon atom; R<2> is hydroxy or an in vivo hydrolysable ester thereof; R<3> is ortho to R<2> and is hydroxy or an in vivo hydrolysable ester thereof; and R<4> has various values. The use of such compounds as antibacterial agents is described as are processes for their preparation and intermediates therefor.