Analysis of substituent effects in the reactions of some2-L-3-nitro-5-X-thiophenes with aniline in benzene. A new interpretation ofthe`element effect`

Abstract

The kinetic constants for the title reactions have been measured in benzene, at 25 \ub0C, at various aniline concentrations. In spite of the low kB/k0 ratios, the reactions are inferred to be genuinely base-catalyzed. The susceptibility constants estimated for the various steps of the reaction mechanism(s) have allowed to make clear the limits of the so-called "element effect" criterion