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

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 3.5 ml portion of acetonitrile was added to 0.946 g of 7-amino-3-(2-carboxybenzoyloxy)methyl-3-cephem-4-carboxylic acid and 0.32 g of 5-mercapto-1-methyl-1H-tetrazole, and the mixture was cooled over a dry-ice/ethanol bath, followed by adding through a dropping funnel 3.71 g of DCPA to it with stirring and rinsing the funnel with 1.0 ml of acetonitrile. The external bath was removed, and the reaction mixture was warmed to 0° C., whereby the starting materials dissolved. The solution was stirred at 14° to 16° C. for 40 minutes to allow the reaction to proceed, and the reaction solution was cooled with ice, and poured into ice-water, which was placed in a refrigerator overnight. The precipitate was filtered out and washed with 10 ml of water, and the filtrate and washing were combined and adjusted to pH 4.0 with 25% aqueous ammonia under ice cooling. The precipitated powder was recovered by filtration, washed with water and acetone successively, and dried, thereby affording 0.710 g (86.5% of yield) of 7-amino-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid. The IR and NMR values of the product were in accordance with those of the authentic sample.

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