Semi-preparative high-performance liquid chromatographic separation of ceralure and related isomers

Summary A semi-preparative high-performance liquid chromatographic procedure on 5-m silica was developed for the isolation of gram quantities of ethyltrans-5-iodo-trans-2-methylcyclohexane-1-carboxylate (B₁) and ethyltrans-4-iodo-trans-2-methylcyclohexane-1-carboxylate (B₂) for comparative evaluation as male Mediterranean fruit fly,Ceratitis capitata, attractants and for NMR studies. This procedure can also be used analytically to determine the content of B₁ (the attractive isomer) in ceralure, the ethyl 4- and 5-iodo-trans-2-methylcyclohexane-1-carboxylate mixture. 1,1-Dimethylethylcis-5-iodo-trans-2-methylcyclohexane-1-carboxylate (A) and 1,1-dimethylethylcis-4-iodo-trans-2-methylcyclohexane-1-carboxylate (C) were isolated and converted to their ethyl esters, thus supplying the fourtrans-isomers of ceralure.