Benzoyl Peroxide → tert-Butyl 3-(bromomethyl)-1H-pyrazole-1-carboxylate

Participants

Reaction Steps

3-methyl pyrazole 1-carboxylic acid tert-butyl ester (4.0 g, 21.95 mmol) was dissolved in 73 mL of CCl4. N-bromosuccinimide (5.47 g, 30.73 mmol) and benzoyl peroxide (744 mg, 3.07 mmol) were added. This solution was warmed to reflux for 5.5 hours and then cooled to room temperature. The reaction mixture was diluted with ethyl acetate and saturated NaHCO3 solution. The phases were separated, and the organic phase was extracted with brine, dried over Na2SO4, filtered and concentrated to give a yellow oil. Purification by column chromatography (SiO2, ISCO chromatography system, elution with 5 to 10% ethyl acetate in hexanes) provided 3-bromomethyl pyrazole 1-carboxylic acid tert-butyl ester (53-2) as a pale yellow oil (2.94 g, 51% yield). 1H NMR was consistent with desired product.

Provenance & Evidence