Process for separating optical isomers of substituted cyclopropane carboxylic acids; amine salts of substituted cyclopropane carboxylic acids; a substituted cyclopropane carboxylic acid

摘要

A process for separating the individual optically active isomers of cis- or trans-forms of cyclopropane carboxylic acids of formula: IMAGE wherein R1 is halo, alkyl, alkenyl, haloalkyl, haloalkenyl or haloalkynyl, and R2 is hydrogen or cyano, from a mixture of cis-isomers or trans-isomers which comprises treating an aqueous solution of a soluble salt of the racemate or diastereoisomeric mixture of the cis- or trans-isomers with just sufficient of a single isomer of an optically active amine to cause precipitation of one isomer or diastereoisomer of the cyclopropane carboxylic acid as the ammonium salt while substantially all of the other isomer remains in solution as the soluble salt.