Method of producing S-(−)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid and product obtained by the method
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United States of America Patent
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Dec 20, 2011
Grant Date -
Mar 11, 2010
app pub date -
Oct 25, 2007
filing date -
Oct 26, 2006
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Expired
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Abstract
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.
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