7.alpha.-Methoxycephalosporins

A 7.alpha.-methoxy-cephalosporin or a salt thereof, said 7.alpha.-methoxy-cephalosporin being represented by the formula ##STR90## wherein R.sup.1 represents a hydrogen atom or a carboxyl-protecting group;

• R.sup.2 represents a substituted or unsubstituted lower alkoxy, lower alkylthio, or C.sub.1-10 acyloxy group, the substituent of the substituted group being selected from halogen, lower alkyl, phenyl, C.sub.2-5 alkenyl, hydroxyl, lower alkoxy, lower alkylthio, nitro, cyano, lower alkylamino, di-lower alkylamino, C.sub.1-10 acylamino, C.sub.1-10 acyl, C.sub.1-10 acyloxy, C.sub.1-10 acyl-lower alkyl, carboxyl, carbamoyl, amino-lower alkyl, N-lower alkylamino-lower alkyl, N,N-di-lower alkylamino-lower alkyl, hydroxy-lower alkyl, hydroxyimino-lower alkyl, lower alkoxy-lower alkyl, carboxyl-lower alkyl, sulfo-lower alkyl, sulfo, sulfamoyl-lower alkyl, sulfamoyl, carbamoyl-lower alkyl, carbamoyl-C.sub.2-5 alkenyl, and N-hydroxycarbamoyl-lower alkyl;
• R.sup.3 represents a lower alkyl group;
• n is 0, 1 or 2;
• A represents a hydrogen atom or a substituted or unsubstituted straight or branched chain C.sub.1-14 alkyl group, the substituent of the substituted group being selected from halogen, lower alkoxy, cyano, nitro, carboxyl, lower alkoxycarbonyl, lower alkylthio, and C.sub.1-10 acyl;
• and B represents a substituted or unsubstituted C.sub.5-6 cycloalkyl, C.sub.5-6 cycloalkenyl, C.sub.5-6 cycloalkadienyl or heterocyclic group, said heterocyclic group being composed of a 5 or 6 membered aromatic heterocyclic ring which is composed of carbon and at least one hetero atom selected from S, O and N, or of said aromatic heterocyclic ring fused to a benzene ring, the substituent of the substituted group being selected from halogen, lower alkyl, lower alkoxy, hydroxyl, C.sub.1-10 acyl, C.sub.1-10 acyloxy, mercapto, lower alkylthio, nitro, amino, protected amino, imino, protected imino, and carboxyl.