| abstract |
Title cmpds. are of formula I:- where R' = H, opt. substd. (1-4C) alkyl, opt. substd. aryl, thienyl or furyl, R2 (>1C) acyl; R3 = H, azido, or heterocyclic thio, and M = H or a non-toxic cation. I are prepd. a) by acylating the 7-amino 3-substd. cmpds. with R1CH(OR2)COZ where Z is OH or an active gp., or with R1CHOH.COZ followed by further acylation with R2Z b) by reacting a 3-acetyl deriv. with R3Z1 where Z1 is H or a cation or c) from cephalosporin C. |