5-Nitroindazole → 1-(3-fluorobenzyl)-5-nitro-1H-indazole

Participants

Reaction Steps

Sodium hydride (NaH) 95% (0.81 g, 34.1 mmol) was added to a solution of 5-nitro-1H-indazole Compound 4a (5.3 g, 32.5 mmol) in DMF (33 mL) at 0° C. under nitrogen. The mixture was stirred for 1 hour at RT, then 1-bromomethyl-3-fluoro-benzene Compound 4b (6.14 g, 32.5 mmol) was added dropwise at 0° C. After stirring at RT for 12 hours, the reaction mixture was partitioned between ethyl acetate and icy water. The organic layer washed with water, brine, dried (Na2SO4), filtered and the solvent evaporated in vacuo to yield a crude solid. The crude solid was purified via flash chromatography (100% dichloromethane) to yield 1-(3-fluoro-benzyl)-5-nitro-1H-indazole Compound 4c (4.02 g, 46%) as a solid. 1H NMR (400 MHz, CDCl3) δ 8.76-8.75 (1H, m), 8.27-8.23 (2H, m), 7.40-7.38 (1H, m), 7.33-2.27 (1H, m), 7.01-6.97 (2H, m), 6.89-6.86 (1H, m), 5.64 (2H, s); MS (ES+) m/z 272.1 (MH+).

Provenance & Evidence