2-Carboxythiophene 2-TCA 2-Thenoic acid 2-Thienylcarboxylic acid 2-Thiophenecarboxylic acid 2-Thiophenic acid 25112-68-9 5-18-06-00158 (Beilstein Handbook Reference) 527-72-0 AI3-16118 BRN 0110150 EINECS 208-423-4 NSC 2188 THIOPHENE-2-CARBOXYLIC ACID Thiophene-2-carboxylate alpha-Thiophenecarboxylic acid