Synthesis and Resolution of Tetrahydropyran Carboxylic Acids and the Bioevaluation of Their Esters as Cockroach Attractants

Abstract

Tetrahydropyran-2- and -3-carboxylic acids were resolved by using quinine. The enantiomeric purity of the corresponding methyl esters (1 and 2) was determined by proton NMR, using a lanthanide chiral shift reagent [Eu(hfc)₃] in the ratio 1 : 3 (substrate/shift reagent). The relative attractant activity of the racemic, and ( + ) and (-) isomers of these esters was evaluated against Blattella germanica (L.) and Supella longipalpa (F.). The results show that the activity order for l was (-)>(+)>racemic, and for 2 was (+)>(-)>racemlc.