The formylation of 7-aminocephalosporanic acid (I) by the usual techniques produces 7-formamidocephalosporanic acid (II), which is then treated with the sodium salt of 1-methyl-1H-tetrazole-5-thiol (III) to yield 7-formamido-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (IV). The resulting product (IV) is deformylated affording 7-amino-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (V), which is finally acylated with anhydro-O-carboxymandelic acid (VI) using the usual techniques.

The formylation of 7-aminocephalosporanic acid (I) by the usual techniques produces 7-formamidocephalosporanic acid (II), which is then treated with the sodium salt of 1-methyl-1H-tetrazole-5-thiol (III) to yield 7-formamido-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (IV). The resulting product (IV) is deformylated affording 7-amino-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (V), which is finally acylated with anhydro-O-carboxymandelic acid (VI) using the usual techniques.

The formylation of 7-aminocephalosporanic acid (I) by the usual techniques produces 7-formamidocephalosporanic acid (II), which is then treated with the sodium salt of 1-methyl-1H-tetrazole-5-thiol (III) to yield 7-formamido-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (IV). The resulting product (IV) is deformylated affording 7-amino-3-(1-methyl-1H-tetrazol-5-ylthio)methyl-3-cephem-4-carboxylic acid (V), which is finally acylated with anhydro-O-carboxymandelic acid (VI) using the usual techniques.