Hydrazine hydrate (1:1) → 5-Allyl-3-(2-fluoro-4-methylphenyl)-4-phenyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 1-(2-fluoro-4-methylphenyl)-2-phenylethanone (1.0 g, 4.38 mmol) in THF (10 mL) was added LiHMDS (1.0 M in THF) (8.76 mL, 8.76 mmol) slowly via syringe at 0° C. After stirring for 10 min, 1-(1H-benzo[d][1,2,3]triazol-1-yl)but-3-en-1-one (0.984 g, 5.26 mmol) was added in one portion. The reaction was stirred at 0° C. for 30 min before quenched with AcOH (2 mL). To the reaction were added EtOH (30 mL), hydrazine hydrate (0.658 g, 13.14 mmol), and heated to reflux for 1 h. After cooled to room temperature, the reaction was concentrated and extracted with EtOAc/H2O, washed with brine, dried over MgSO4, and purified by column chromatography to give the title compound as clear oil (0.50 g). LCMS m/z=293.2 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ ppm 2.31 (s, 3H), 3.40 (d, J=5.94 Hz, 2H), 4.94-5.08 (m, 2H), 5.88-6.00 (m, 1H), 6.92-7.31 (m, 8H).

Provenance & Evidence