Stereoselective electrochemical reduction of imazapyr in aqueous media without chiral auxiliaries

Abstract

The electrochemical reduction of imazapyr at the static mercury drop electrode was studied by cyclic voltammetry as a function of pH in aqueous buffered media. The process leads to the 2,3=CvN double bond reduction in the imidazoline moiety in all media. The products have been isolated by controlled-potential electrolyses and identified by high performance liquid chromatography-tandem mass spectrometry measurements and H-1-NMR, C-13-NMR, and IR spectra. Although no chiral auxiliary was used, a moderate diasteroisomeric excess was observed. The diasteromeric ratio depends on pH of the electrolyses