Benzoyl Peroxide → Tert-butyl 3-(bromomethyl)-6-fluoro-1H-indazole-1-carboxylate

Participants

Reaction Steps

12.68 g (50.7 mmol) 6-Fluoro-3-methyl-indazole-1-carboxylic acid tert-butyl ester, prepared as in Part C, is combined with 9.92 g (55.7 mmol, 1.1 equiv) N-Bromosuccinimide and 1.23 g (5.1 mmol, 0.1 equiv) Benzoyl peroxide in 600 mL CCl4 and refluxed 10 h. The reaction mixture is filtered and the filtrate concentrated in vacuo and purified by flash chromatography on 300 g silica gel eluted successively with DCM/Hexanes (1:2, 3 L), (1:1, 3 L). Appropriate fractions were combined and concentrated in vacuo to give 10.18 g (30.9 mmol) of 3-Bromomethyl-6-fluoro-1-tert-butoxycarbonyl-1H-indazole as an amber oil: 1H NMR (CDCl3, 300 MHz) δ7.82 (m, 2H), 7.13 (m, 1H), 4.76 (s, 2H), 1.72 (s, 9H); TLC Rf =0.17 (EtOAc/Hexanes, 1:19).

Provenance & Evidence