Synthesis and preliminary pharmacological study of thiophene analogues of the antipyretic and analgesic agent ethenzamide.

A preliminary pharmacological study of a thiophene analogue 1b of the analgesic and antipyretic agent Ethenzamide and of a closely related compound 1a showed that a great similarity exists among Ethenzamide and the thiophenic compounds for analgesic, antipyretic, ulcerogenic, hypothermic, and sedative effects. However, the acute toxicity in mice for the thiophenic compounds is notably higher than that of Ethenzamide.