N-bromobutanimide → tert-Butyl 3-(bromomethyl)-1H-pyrazole-1-carboxylate

Participants

Reaction Steps

3-Methylpyrazole-1-carboxylic acid tert-butyl ester (6.0 g, 33 mmol), N-bromosuccinimide (1.0 g, 5.6 mmol) and benzoyl peroxide (50 mg) were dissolved in 20 mL of carbon tetrachloride. The reaction was heated at reflux for 16 h. The reaction was cooled to room temperature, filtered, and concentrated under reduced pressure. Purification by flash column chromatography (silica, 1:4 EtOAc/hexanes) gave a light yellow oil (4.5 g, 53%): 1H NMR (300 MHz, CDCl3) δ 8.03 (d, J=2.6 Hz, 1H), 6.47 (d, J=2.6 Hz, 1H), 4.48 (s, 2H), 1.64 (s, 9H).

Provenance & Evidence