Enzymatic deprotection of the cephalosporin 3'-acetoxy group using Candida antarctica lipase B.

Cephalosporins remain one of the most important classes of antibiotics. A useful site for derivatization involves generation of and chemistry at the 3'-hydroxymethyl position. While 3'-acetoxymethyl-substituted cephalosporins are readily available, deacetylation to access the free 3'-hydroxymethyl group is problematic when the carboxylic acid is protected as an ester. Herein we report that this important transformation has been efficiently accomplished using Candida antarctica lipase B. Although this transformation is difficult to carry out using chemical methods, the enzymatic deacetylation has been successful on gram scale, when the cephalosporin is protected as either the benzhydryl or tert-butyl esters and on the corresponding sulfoxide and sulfone of the tert-butyl ester.