TRANSMISSION OF ELECTRONIC EFFECTS THROUGH THE VINYL GROUP - REACTIVITIES OF THE (E)-ALPHA-4-SUBSTITUTED PHENYL-BETA-PYRIDINE-ACRYLIC ACIDS

The reactivities of a series of 18 (E)-alpha-4-substituted phenyl-beta (3N and 4N)pyridineacrylic acids, with a wide range of substituent eff ects, were investigated in their reaction with diazodiphenylmethane, i n dimethylformamide at 30-degrees-C, by the known spectrophotometric m ethod. The Hammett equation in its original form has been applied to t he results, using the sum of substituent constants from the both aroma tic nuclei, but the overall correlation was only fair. Better insight into the transmission of substituent effects was obtained using Taft's Dual Substituent Parameter (DSP) method, where it was possible to dis tinguish the contributions from the inductive and resonance effects of the substituents.