Bromine → HCID 57416989, compound

Participants

Reaction Steps

A solution of 1-(4-chlorophenyl)pyrazole (834 mg, 4.67 mmol) in acetic acid (10 mL) is treated with bromine (0.26 mL, 5.08 mmol). After stirring for 18 h, the solution is diluted with 40 mL water, and satd. aq. NaHSO3 solution is added until the bromine color had dissipated. Then, solid sodium bicarbonate is added until a neutral pH is obtained. This mixture is extracted with ethyl acetate (2×50 mL), and the extracts are washed with brine, combined, dried over MgSO4, filtered and evaporated. The solid residue is recrystallized from cyclohexane to afford pure product, 4-bromo-1-(4-chlorophenyl)-pyrazole (797 mg, 3.10 mmol, 66%). m.p. 75-76° C. (cyclohexane), 1H NMR (300 MHz, CDCl3): δ 7.89 (1H, s), 7.66 (1H, s), 7.57 (2H, d, J=9.0 Hz), 7.41 (2H, d, J=9.0 Hz). MS (ES+): m/e 261 (26), 259 (100), 257 (77).

Provenance & Evidence