Synthesis, intramolecular cyclization, and antinociceptive activity of 4-(het)aryl-2-{[4-(4-chlorophenyl)-3-(ethoxycarbonyl)thiophen-2-yl]amino}-4-oxobut-2-enoic acids

Synthesis and intramolecular cyclization of the substituted 4-(het)aryl-2-{[4-(4-chlorophenyl)-3-(ethoxycarbonyl)thiophen-2-yl]amino}-4-oxobut-2-enoic acids were studied. It was found that the synthesized compounds underwent the intramolecular cyclization to give the substituted ethyl 4-(4-chlorophenyl)-2-{[2-oxofuran-3(2 H )-ylidene]-amino}thiophene-3-carboxylates. Evaluation of the biological activity of the synthesized compounds showed that they have pronounced antinociceptive activity along with low toxicity.