Synthesis of 1‐aryl‐5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxylic acids and esters

Abstract

Abstract Ethyl 1‐aryl‐5‐(trifluoromethyl)‐1 H ‐pyrazole‐4‐carboxylates 2 were prepared by the condensation of arylhydrazines with ethyl 3‐ethoxy‐2‐(trifluoroacetyl)‐2‐propenoate (1a) at low temperature. The corresponding acids were also synthesized. X‐ray diffraction analysis of an amide derivative 4 verified the position of the trifluoromethyl group on the pyrazole ring.