Hydrochloric Acid → 7-Amino-3-(1-methyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylicacid

Participants

Reaction Conditions

Reaction Steps

A solution of 72.5 g of 1-methyl-5-mercapto-1,2,3,4-tetrazole (MTA) in 87.5 ml of triethylamine in 3 liters of water was heated to 75° C. 68 g of 7-aminocephalosporanic acid (92%) were added, to give a suspension with pH 4.35. 28 ml of triethylamine were added at the same temperature and the solution thus formed, with pH 5.20, was held for 30 min at 75° C. and 60 min at 53° C. Throughout the whole operation the reaction isoelectric pH was held to 5.25 with the gradual addition of a solution of 20 g of thiol (MTA) in 175 ml of water. The formation rate of the precipitate increased on cooling to 53° C. The mixture was adjusted to pH 4.25 at 25° C. with concentrated hydrochloric acid. It was filtered, washed with water and then acetone to give 52.8 g of the compound of the title with a 70% yield. It was recrystallised out of an aqueous hydrochloric acid solution at pH 2.20 and isolated with a m.p. 224° C. (d).

Provenance & Evidence