NATURAL ABUNDANCE O-17 NMR-STUDY OF 2-SUBSTITUTED AND 4-SUBSTITUTED BENZOYL CHLORIDES

Natural abundance O-17 NMR chemical shift data for 17 ortho and para benzoyl chlorides recorded in acetonitrile at 75-degrees-C are reported. O-17 NMR data for the para substituted benzoyl chlorides are correlated with O-17 NMR data for similarly substituted acetophenones and methyl benzoates. The O-17 NMR signals for ortho isomers are downfield (ca 30 ppm) from their para isomers; the downfield shifts are consistent with torsion angle change. The O-17 NMR data for the para isomers gave good correlations with sigma+ constants and with dual substituent parameters (DSP).