NMR Characterization of Some Chlorinated Hydrocarbon Pesticides, their Metabolites, Derivatives and Complexes

Abstract

Pmr spectroscopy has been used to assess the stereochemistry of various chlorinated hydrocarbon pesticide metabolites of the DDT and polycyclodiene type employing essentially all available techniques, such as spin decoupling, selective lanthanide shift reagents, as well as the Fourier transform system. Both achiral and chiral shift reagents were particularly helpful in determining stereoselective and stereospecific chemical and biological transformations of the chlorinated polycyclodiene compounds. Chemical shift measurements of the benzhydryl and aromatic proton resonances of various compounds related to DDT (isomers, metabolites and their derivatives) provided diagnostic stereoelectronic information. Previous work has shown that DDT can undergo two types of complexation, one involving the benzhydryl proton and trichloromethyl grouping with polar complexing agents, and the other interaction of the DDT aromatic n-electron system with the π-electrons of a complexing molecule. In respect to these studies an attempt has been made to classify according to binding type some of the DDT compounds studied on the basis of the experimental patterns in the pmr data. Sufficient information is not available at this time to allow a meaningful correlation to be drawn between binding propensities and toxicity data.