PRODUCTION OF 3-O-SUBSTITUTED-ASCORBIC ACID

PURPOSE: To obtain a 3-O-substituted-ascorbic acid having antioxidizing activity and useful for preventing deterioration of food qualities, etc., by a VIC-glycol formation reaction through ring-opening of a dioxolan ring in a starting material in a reaction system consisting of a non-aqueous solvent and an acidic ion exchanging resin. CONSTITUTION: This method for producing a 3-O-substituted-ascorbic acid is to treat a 3-O-substituted 5,6-O-isopropylideneascorbic acid (A) of formula I (R is a lower alkyl, a lower alkylcarbonyl-lower alkyl group) with an acidic ion exchange resin in a non-aqueous solvent (preferably a primary alcohol, an ether, an ester, etc.), open a dioxolan ring in the formula I, form a VIC-glycol group and obtain a 3-O-isopropylideneascorbic acid (B) of formula II, e.g. 3-O- ethylascorbic acid obtained from L-3-O-ethyl-5,6-O-isopropylideneascorbic acid. The ion exchange resin preferably contains sulfonic acid group and/or carboxylic acid group as effective functional groups.