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AssigneeMitsubishi Gas Chemcial Company, Inc.
InventorsAkifumi Iida, Youichi Kyuuko, Toshio Hidaka
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The present invention provides an industrially available method for efficiently producing high-purity S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid excellent in solid-liquid separability from an S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid ester, and also provides products obtained by the method. Under a temperature condition of 50-80° C. in an aqueous solvent, (A) an S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid ester represented by the general formula (1) is hydrolyzed under a basic condition for 1-3 hours; then (B) the insoluble matters contained in the reaction solution resulting from the hydrolysis are removed; and (C) an acid is added to the resulting solution to effect crystallization; provided that R in the general formula (1) represents an alkyl or aryl group.
A method for producing S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid under a temperature condition of 50-80° C. in an aqueous solvent by hydrolysis of an S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid ester represented by general formula (1), which comprises (A) hydrolyzing an S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid ester represented by general formula (1) under a basic condition for 1-3 hours, then (B) removing insoluble matters contained in the reaction solution resulting from the hydrolysis, and (C) adding an acid to the resulting solution to effect crystallization.
Dependencies are inferred from the claim text.