Catalysis in aromatic nucleophilic substitution. Part 9. Kinetics of the reactions of 2-bromo-3,5-dinitrothiohene with some meta- and para-substituted anilines in benzene

Abstract

The rate constants of debromination of 2-bromo-3,5-dinitrothiopene by various meta- and para-substituted anilines have been measured in benzene at 25 °C. The reactions are mildly accelerated by increasing the amine concentration, showing ‘low’k_B/k₀ ratios (4.6–11 dm³ mol^–1). However, the reactions are inferred to be genuinely base-catalysed on the grounds of the excellent Hammett-type relationships ollowed by both log k_B and log k₀ parameters.