3‐Oxo‐4,4,4‐trifluorobutyronitriles as building blocks of trifluoromethyl substituted heterocycles 2. Heterocyclization to 3‐aryl‐4‐trifluoromethyl‐2H‐1‐benzopyran‐2‐ones under hoesch reaction conditions

Resorcinol and 5‐methylresorcinol, respectively, react with 3‐oxo‐2‐aryl‐4,4,4‐trifluorobutyronitrile using zinc chloride as a catalyst in dibutyl ether under the Hoesch reaction conditions to give a low yield of 3‐aryl‐7‐hydoxy‐4‐trifluoromethyl‐ or 3‐aryl‐5‐hydroxy‐7‐methyl‐4‐trifluoromethyl‐2H‐l‐benzopyran‐2‐ones. However, the related reaction with m‐methoxyphenol was found to produce poor yields of 3‐aryl‐7‐methoxy‐4‐trifluoromethyl‐2H‐1‐benzopyran‐2‐one and its 3,4‐dihydro‐4‐hydroxy derivative.