Ethyl 4,4,4-trifluoroacetoacetate → 3H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-

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Reaction Conditions

Reaction Steps

A mixture of 5 g (27.2 mmol) of ethyl trifluoroacetoacetate and 4.86 g (27.2 mmol) of 2-chlorophenylhydrazine hydrochloride in 50 ml of acetic acid was heated at 100° C. with stirring overnight. The mixture was concentrated in vacuo (70° C.), the residue was disolved in methanol and concentrated in vacuo. The residue was triturated in methylene chloride, cooled (0° C.), and the white solid was filtered to afford 3.01 g (42%) of 2,4-dihydro-2-(2-chlorophenyl)-5-trifluoromethyl-3H-pyrazol-3-one (Formula III: R1 =2-Cl--Ph; R2 =CF3 ; R3=H) as a white solid.

Provenance & Evidence