Cephalosporin derivatives.

摘要

Derivatives of substituted cephalosporanic acid represented by the formula (I):
<CHEM>
wherein R<1> represents a 4-pyridylthiomethyl, alpha-aminobenzyl, cyanomethyl or 1-tetrazolylmethyl group; R<2> represents a hydrogen atom or an acetoxy or (5-methyl-1,3,4-thiadiazol-2-yl)thio group; R<3> represents a hydrogen atom, a hydroxyl group, a carbamoyl group, an alkyl group having 1 to 4 carbon atoms or-(CONH)m(CH2)n-COOH wherein m is 0 or 1, n is 0, 1 or 2 and the carboxyl group may have been converted to a salt or an ester thereof; p is 0, 1 or 2; and X represents a carbon atom or nitrogen atom; are useful as ibiotics.