Synthesis of 6-O-Octanoyl-1,2-O-isopropylidene-α-D-glucofuranose by Lipase-catalyzed Esterification in an Organic Solvent

Abstract

The synthesis of 6-O-octanoyl-1,2-O-isopropylidene-α-D-glucofuranose (C8-IpGlc) via the lipase-catalyzed esterification of 1,2-O-isopropylidene-α-D-glucofuranose (IpGlc) with octanoic acid was evaluated using ketones, nitriles, and tertiary alcohols as reaction media. Among the solvents assessed, acetone was the most effective solvent for the synthesis of C8-IpGlc at 50°C, without the formation of a by-product (a diester of IpGlc); the optimum molar ratio of octanoic acid:IpGlc was 2:1. Notwithstanding early-stage substrate inhibition by IpGlc at initial IpGlc concentrations greater than 250 mmol/L, an optimal product concentration of ca. 210 mmol/L (conversion = 53 % at 7 d) was achieved at longer reaction times by changing the initial IpGlc concentration from 25 to 800 mmol/L.