Patent ID: 6713639
Filing Date: 2004-03-30
Classification: C07D

Abstract:
A process for the preparation of enantiomerically pure (S)-3-hydroxy-&ggr;-butyrolactone said process comprising(i) dissolving a D-hexose source in an aqueous alkali solution, (ii) heating the solution to a temperature in the range of 40Â° C. to 50Â° C. for a period of 1 to 4 hours to obtain a dark yellow to dark red color solution, (iii) adding a peroxide reagent to the solution, (iv) raising the temperature of the solution to about 70Â° C. for 8 to 24 hours to obtain a reaction mixture of 3,4-dihydroxybutyric acid and glycolic acid, (v) cooling the reaction mixture to a temperature of about 25Â° C., (vi) adding an acid to the reaction mixture to about pH 1.0, (vii) evaporating the reaction mixture of step (vi) to dryness to remove water and glycolic acid to obtain a yellow syrup, (viii) neutralizing the yellow syrup with a solid base, (ix) extracting with an organic solvent, (x) drying the organic layer over anhydrous sodium sulfate to obtain a residue, and (xi) purifying the residue over a silica gel column using a mixture of organic solvents as an eluant to obtain the pure compound (S)-3-hydroxy-&ggr;-butyrolactone.