Acetic Acid → 1H-Pyrazole, 1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-3,5-dimethyl-

Participants

Reaction Steps

Pentan-2,4-dione (0.100 g) was added to a stirred solution of 2,6-dichloro-4-trifluoromethylphenylhydrazine (0.245 g) in ethanol (4.5 ml), followed by glacial acetic acid (0.5 ml), at room temperature. The reaction mixture was heated under reflux for 1 hour, then evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, using dichloromethane as eluant, to provide a colourless oil initially which crystallised, after removal of extraneous solvent in vacuo, to furnish the title compound (0.265 g), m.p. 87-89° C. δ(CDCl3): 2.10 (s,3H), 2.32 (s,3H), 6.07 (s,1H), 7.72 (s,2H). MS (thermospray): M/Z [M] 309.0; C12H9Cl2F3N2 requires 309.12.

Provenance & Evidence