| 摘要 |
2128522 9315034 PCTABS00024 A method for racemizing an optically active carboxylic acid, or ester thereof, of formula (I), where R1, is hydrogen or C1 to C6 linear or branched alkyl; R2, R3 and R4 are different and are hydrogen or C1 to C6 linear or branched alkyl, C1 to C6 linear or branched haloalkyl, aralkyl, cycloalkyl, alkyl substituted cycloalkyl, C6 to C10 aryl, C1 to C6 linear or branched alkoxy, C6 to C10 aryloxy, C1 to C6 alkylthio, C2 to C8 cycloalkylthio, C6 to C10 arylthio, C6 to C10 arylcarbonyl, C4 to C8 cycloalkenyl, trifluoromethyl, halo, C4 to C5 heteroaryl, C10 to C14 aryl, or biphenyl unsubstituted or substituted with methyl or halo, comprising heating said optically active carboxylic acid or ester thereof in the presence of water at a temperature of from 75 ·C to 200 ·C in the presence of a catalytically effective amount of an aliphatic, aromatic or mixed aliphatic and aromatic tertiary amine for a time sufficient to racemize said carboxylic acid or ester thereof.
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