Methyl iodide → 4-Bromo-5-isopropyl-1-methylindazole

Participants

Reaction Conditions

Reaction Steps

A solution of 4-bromo-5-isopropylindazole (27) (488 mg, 2.04 mmol) in 5 nml of anhydrous DMF is added to a suspension of sodium hydride (122 mg, 60% in mineral oil, 3.06 mmol, 1.5 eq.) in 5 ml of DMF under nitrogen at 0° C. The resulting mixture is stirred at 0° C. for 30 minutes, then warmed to room temperature. After stirring at room temperature for an additional 2 hours, the reaction mixture is cooled to 0° C., and iodomethane (318 mg, 2.24 mmol, 1.1 eq.) is added dropwise, the mixture is stirred at 0° C. for 2 hours, then warmed to room temperature, and stirred overnight. The reaction mixture is poured into 30 ml of ice-water, extracted with ethyl acetate (30 ml×3), washed with water and brine, and dried over anhydrous sodium sulfate. The solvent is evaporated and the product is purified via flash chromatography to give 340 mg of 4-bromo-5-isopropyl-1-methylindazole 1H NMR (400 MHz, CDCl3) 7.95 (1H, s), 7.31 (2H, S), 4.05 (3H, S), 3.55 (1H, m), 1.27 (6H, d, J=6.8 Hz). MS (+VE) m/z 253(M+). 165 mg of 4-bromo-5-isopropyl-2-methylindazole (28). 1H NMR (400 MHz, CDCl3) δ 7.82 (1H, s), 7.59 (1H, d, J=9.2 Hz), 7.21 (1H, d, J=8.8 Hz), 4.16 (3H, s), 3.50 (1H, m), 1.21 (6H, d, J=6.8 Hz). MS (+VE) m/z 253(M+).

Provenance & Evidence