Synthesis of Thiophene Carboxamide Derivatives and Inhibitory Activity againstGaeumannomyces graminisvar.tritici.

Abstract

The procedures for synthesizing the substituted ester 2-hydrothiophene-3-carboxylate and its silanization were explored. The reaction conditions were optimized. And with the substituted thiophene as the framework, 20 new thiophene carboxamide derivatives were synthesized. The chemical structures of thiophene carboxamide derivatives were confirmed by 1 H NMR, 13 C NMR, HRMS or elemental analysis techniques. The inhibitory activity against Gaeumannomyces graminis var. tritici was evaluated in vitro by the plate method. The preliminary structure-activity relationship indicated that the substituent bonded to the amide nitrogen atom and the steric hindrance of the substituent at 2nd position of the thiophene carboxamide had a significant influence on the activity. The compounds 7b~7d, 7l, 7m and 7o exhibited very high inhibitory activity. The results would be helpful for the design of lead compounds. Keywords thiophene carboxamide derivative; synthesis; Gaeumannomyces graminis var. tritici.; inhibitory activity