Three-Bond 13C-1H Coupling Constants for Chrysanthemic Acid and Phenothrin Metabolites: Detection by Two-Dimensional Long-Range 13C-1H J-Resolution Spectroscopy

Article abstract of DOI:10.1002/mrc.1260310118

Two-dimensional long-range 13C-1H J-resolution spectroscopy (LRCJR) was used to measure three-bond 13C-1H coupling constants <³J(C,H)> for trans- and cis-chrysanthemic acid, methyl trans-pyrethrate and some microsomal metabolites of the trans-chrysanthemate biophenothrin.The carbon of the methyl cis-disposed to an attached proton shows a larger ³J(C,H) value than does the trans-carbon for the dimethyl-substituted cyclopropane and epoxide rings.The reverse situation applies for the analogous dimethyl vinyl grouping.The ³J(C,H) values are not altered on conversion of one of the olefinic geminal methyl groups to a hydroxymethyl or methoxycarbonyl functionality, but increase on transformation to an aldehyde.These ³J(C,H) values are in agreement with previous results from long-range C-H COSY experiments, and provide a useful method for determining the stereochemistry of chrysanthemic acid derivatives. KEY WORDS: Long-range 13C-1H coupling constants, Long-range 13C-1H J-resolution spectroscopy, Chrysanthemic acid, Pyrethroid, 2D NMR