Acetyl chloride → 1H-Pyrazole,3-methyl-5-phenyl-

Participants

Reaction Steps

To a solution of acetophenone (10 g, 83 mmol) in anhydrous toluene (10 mL) was added LiHMDS (1.0 M in THF, 83 mL, 83 mmol) via syringe at 0° C. under argon. After 5 min, acetyl chloride (6.53 g, 83 mmol) was added via syringe in one portion. The ice bath was removed and AcOH (5 mL, glacial), EtOH (50 mL), and hydrazine hydrate (12.50 g, 250 mmol) were added. The mixture was refluxed for 2 h, cooled to room temperature, and neutralized to pH 7 by adding 1.0 M NaOH solution. The mixture was extracted with EtOAc, washed with brine, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography to give the title compound as a pale yellow oil (12.05 g). LCMS m/z=159.0 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ ppm 2.25 (s, 3H), 6.42 (s, 1H), 7.20-7.44 (m, 3H), 7.67-7.82 (m, 2H), 12.53 (bs, 1H).

Provenance & Evidence