| abstract |
3-Acylated-methyl-cephalosporin derivs. of formula (I), their easily hydrolysable ester, pharmaceutically acceptable salts, and their hydrates are new: X = OCO, SCO, NHCO or OCONH; R1 = acyl; R2 = H or lower alkoxy; R3 = a gp. (II)-(IV); R4, R4' and R4'' = H or COR2; R2 = opt. branched lower alkyl; A and B = halo; a, b, x, y and z = zero (corresp. to H at that position) or 1, at least 2 of x, y and z are 1; m = 0-8. Also new are intermediates (XVIII) of similar formula but with R1 replaced by H and the 4-COOH gp. opt. protected. Pref. m = 0 or 1; R4, R4' or R4'' = H or MeCO; A and B = chloro; R = H. |