PROCESS FOR THE PREPARATION OF (S)-GLYCERALDEHYDE ACETONIDE

摘要

The invention relates to a process for the preparation of (S)-glyceraldehyde acetonide in aqueous solution from 3,4-O-­isopropylidene-L-threonic acid or a salt thereof in aqueous solution, and hypochlorite in aqueous solution wherein the aqueous hypochlorite solution has a pH > 7.5 and wherein during addition of at least 0.1 molar equivalents of hypochlorite based on the amount of 3,4-O-isopropylidene-­L-threonic acid, an acid solution is not simultaneously added. The invention also relates to a process according to the invention, wherein 3,4-O-isopropylidene-L-threonic acid or a salt thereof is prepared from 5,6-O-isopropylidene-L-ascorbic acid or a salt thereof in the presence of H2O2 and a base in a manner known per se, wherein excess H2O2 is optionally removed by catalase. The invention also relates to a process according to the invention, wherein 5,6-O-isopropylidene-L-ascorbic acid or a salt thereof is prepared by reacting L-ascorbic acid or a salt thereof with an acetonide forming agent, preferably in the presence of an acid catalyst.