Quantitative determination of the enantiomeric purity of synthetic pyrethroids. Part I. The chrysanthemic acid moiety

Abstract

Chrysanthemic acid is liberated by hydrolysis of the pyrethroid under basic conditions and is made to react with (+)-α-methylbenzylamine via the acid chloride. Complete separation of diastereoisomeric amides derived from the (+) and (–) forms of both cis- and trans-chrysanthemic acids can be obtained by gas chromatography on a 50-m × 0·25-mm glass capillary column coated with FFAP (free fatty acid phase). No racemisation or kinetic resolution takes place during the reaction sequences. The method is suitable for the analysis of bioresmethrin, bioallethrin, tetramethrin and other insecticidal chrysanthemates.