Hydrazine hydrate (1:1) → 5-(2-(Methylthio)ethyl)-4-phenyl-3-p-tolyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 2-phenyl-1-p-tolylethanone (2.0 g, 9.51 mmol) in THF (10 mL) was added LiHMDS (1.0 M in THF) (19.02 mL, 19.02 mmol) slowly via syringe at 0° C. After stirring for 10 min, 1-(1H-benzo[d][1,2,3]triazol-1-yl)-3-(methylthio)propan-1-one (2.53 g, 11.41 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 (1.428 g, 28.5 mmol), and brought to reflux for 2 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 a as clear oil (1.50 g). LCMS m/z=309.3 [M+H]+; 1H NMR (400 MHz, CDCl3) δ ppm 1.96 (s, 3H), 2.29 (s, 3H), 2.66 (t, J=7.71 Hz, 2H), 2.90 (t, J=7.58 Hz, 2H), 7.01-7.06 (m, 2H), 7.18-7.25 (m, 3H), 7.26-7.37 (m, 3H).

Provenance & Evidence