Abstract Reactions of 4-nitrophenyl 2-thiophenecarboxylate (1a-e) with in 20 mol% DMSO (aq) have been studied kinetically. The order kinetics,= 0.88-0.98, and linear Hammett and Yukawa-Tsuno plots observed for these reactions indicate an addition-elimination mechanism in which the step is rate limiting. The value increased with a stronger electron- withdrawing 5-thienyl substituent, the Hammett plots are linear except for X= MeO, and ...
