Hydrazine hydrate (1:1) → 5-Allyl-4-phenyl-3-p-tolyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 2-phenyl-1-p-tolylethanone (1.0 g, 4.76 mmol) in THF (10 mL) added LiHMDS (1.0 M in THF) (9.51 mL, 9.51 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 (1.068 g, 5.71 mmol) was added in one portion. The reaction was stirred at 0° C. for 30 min and then quenched with AcOH (2 mL). EtOH (30 mL) and hydrazine hydrate (0.714 g, 14.27 mmol) were added, and the reaction was heated to reflux for 30 min. The reaction was cooled to room temperature, concentrated and the residue was extracted with EtOAc/H2O, washed with brine, dried over MgSO4, and purified by column chromatography to give the title compound as clear oil (0.47 g). LCMS m/z=275.0 [M+H]+; 1H NMR (400 MHz, CDCl3) δ ppm 2.31 (s, 3H), 3.38-3.43 (m, 2H), 5.07-5.14 (m, 2H), 5.90-6.01 (m, 1H), 7.03-7.09 (m, 2H), 7.19-7.30 (m, 5H), 7.30-7.36 (m, 2H).

Provenance & Evidence