The reaction of 7-beta-bromoacetamido-7-alphamethoxycephalosporanic acid (I) with D-cysteine (II) in water at pH 7 gives 7-(2-aminocarboxyethylthio)acetamido-7-alpha-methoxycephalosporanic acid (III), which is then condensed with 5-mercapto-1-methyl-1H-tetrazole (IV) in water at pH 6.5-7 and at 60 C.
A new method for the synthesis of MT-141 has been reported: By condensation of 7-bromoacetamido-7alpha-methoxy-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (I) with D-cysteine (II) in aqueous NaHCO3.