CEPHALOSPORIN COMPOUNDS

1361183 Cephalosporin compounds GLAXO LABORATORIES Ltd 15 July 1971 [6 Aug 1970] 38021/70 Heading C2A 3-Ethyl and 3-substituted ethyl cephalosporin compounds of general formula (I): wherein R1 is hydrogen or a carboxylic acyl group, R2 is hydrogen or a carboxyl blocking group, R3 and R4 are identical or different and each is a hydrogen atom or an organic group, Z is > S or > S#O, and the dotted line signifies a double bond in the 2,3- or 3,4-position, the said compounds being novel when R3 and R4 are each hydrogen or one of R3 and R4 is hydrogen and the other is cyano, are prepared by reducing a cephalosporin compound of Formula (II) to hydrogenate the methylene group at the 3-position. The reduction may be effected by hydrogenation in the presence of a noble metal catalyst, by treatment with a diimine, or with zinc and an acid (e.g. acetic or formic acid), or with a metallohydride. The compounds (I) have antibiotic activity and may be formulated into pharmaceutical compositions with a suitable diluent or carrier.