Methanol → p-Chloro-0-[1,2-bis(trifluoromethyl)vinyl]acetophenone oxime

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Reaction Steps

Hexafluoro-2-butyne is slowly bubbled through a 55°-60° C. solution of p-chloroacetophenone oxime (17.0 g, 0.10 mol), methanol (80 mL) and potassium tert-butoxide (1.12 g, 0.01 mol) over a 5 hour period. The solvent is removed in vacuo to obtain a liquid which is poured into water and extracted with ether. The combined organic extracts are washed sequentially with water and brine, dried over anhydrous sodium sulfate and concentrated in vacuo to give an oil. The oil is chromatographed using silica gel and eluted with ethylacetate in methylene chloride to 5% ethyl acetate in methylene chloride to give p-chloro-0-[1,2-bis(trifluoromethyl)vinyl]acetophenone oxime, vinyl-(Z) as a yellow liquid (21.5 g, 65%) and 2-(p-chlorophenyl)-4,5-trans-bis(trifluoromethyl)-1-pyrrolin-5-ol as a white solid (2.35 g, mp 152.5°-153° C., 7%).

Provenance & Evidence