A process for the preparation of optically active 2-[4-(2',4'-dihalophenoxy)phenoxy]propionic acids of at least 75 percent enantiomeric excess of the desired optical isomer which comprises contacting a 2-chloropropionic acid or a lower alkyl ester or an alkali metal salt thereof, having an optical purity of greater than 90 percent of the opposite configuration, with from 2 to 10 molar equivalents of a 4-(2',4'-dihalphenoxy)phenol in an aqueous base.
一种制备光学活性的2-[4-(2',4'-二卤代苯氧基)苯氧基]
丙酸的方法,其至少具有75%的所需光学异构体的对映体过量,包括将光学纯度大于90%的相反构型的
2-氯丙酸或较低的烷基酯或其碱
金属盐与2-10摩尔当量的4-(2',4'-二卤代苯氧基)
苯酚在
水性碱中接触。