CEPHALOSPORIN DERIVATIVES

摘要

A cephalosporin derivative of the formula: I in which R0 is a hydrogen atom or a methyl radical, R1 is any one of the C-3 substituents from antibacterially-active cephalosporins known in the art; R2 is any one of the C-4 substituents from antibacterially-active cephalosporins known in the art; R3 is a hydrogen atom or a 1-6C alkoxy or 1-6C alkylthio radical; X1 is a sulphur or oxygen atom, a CH2 radical or a radical of the formula NR7 in which R7 is a hydrogen atom, a 1-6C alkyl, formyl or benzyl radical; X2 is a nitrogen atom or a radical of the formula N(+)-R7; R4 and R7, and R5 and R6 are a variety of substituents which are described in the specification; and the pharmaceutically-acceptable acid- or base-addition salts thereof. Pharmaceutical compositions, manufacturing processes and intermediates are also described.