REGIOSELECTIVE ACYLATION OF DISACCHARIDES IN TERT-BUTYL ALCOHOL CATALYZED BY CANDIDA-ANTARCTICA LIPASE

The acylation of several disaccharides by ethyl butanoate and ethyl do decanoate was catalyzed by Candida antarctica lipase in tert-butyl alc ohol, at temperatures ranging from 40 degrees to 82 degrees C (reflux temperature). The relative reaction rates of the various disaccharides were directly related to their solubility. The primary products were the monoesters derived from acylation of the primary alcohol groups. A t higher conversions diesters were formed, and the ratio of diester to monoester was markedly dependent on the structure of the disaccharide . Thus, reaction of maltose with ethyl dodecanoate in refluxing tert-b utyl alcohol afforded the 6'-monododecanoate even at high conversions. Trehalose, in contrast, afforded the 6,6'-diester. Acylation of the l ess soluble sucrose and lactose was much slower, but a moderate (37%) conversion of sucrose was observed after a prolonged reaction time (7 days). A number of other lipases and proteases were tested but C. anta rctica lipase was unique in catalyzing the acylation of sucrose in ref luxing tert-butyl alcohol. (C) 1996 John Wiley & Sons, Inc.