Monoacylation of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid by protease in N,N-dimethylformamide with low water content.

2-O-alpha-D-Glucopyranosyl-L-ascorbic acid (AA-2G) laurate was synthesized from AA-2G and vinyl laurate with a protease from Bacillus subtilis in N,N-dimethylformamide (DMF) with low water content. Addition of water to DMF dramatically enhanced monoacyl AA-2G synthesis. Maximum synthetic activity was observed when 3% (v/v) water was added to the reaction medium. Under the optimal reaction conditions, 5-O-dodecanoyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acid, 2-O-(6'-O-dodecanoyl-alpha-D-glucopyranosyl)-L-ascorbic acid, and 6-O-dodecanoyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acid were synthesized in yields of 5.5%, 3.2%, and 20.4%, respectively.