Ammonia → Cephalexin

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

21.4 g of 7-aminodesacetoxycephalosporanic acid were suspended in 450 ml of acetonitrile, and then 17.7 g of hexamethyldisilazane were added to the suspension. The mixture was heated to 65° C. for 2 hours under a nitrogen atmosphere and then cooled to 15° C. 22 g of N-methylpyrrolidone were added. After 10 minutes, 22.5 g of D(-)-phenylglycyl chloride hydrochloride were added and the mixture was stirred at 15° C. for 4 hours and then added to 500 ml of water at 10° C. Aqueous ammonia was then added to the reaction mixture to precipitate the desired product which, after 10 hours, was filtered off and dried. 25 g of cephalexin [7-(D-α-aminophenylacetamido)desacetoxycephalosporanic acid] were obtained. Iodometric assay against an authentic sample showed that the product was 98.7% pure.

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