Dimethylformamide → 1-Methyl-1H-indazole-5-carboxaldehyde

Participants

Reaction Conditions

Reaction Steps

A suspension of n-BuLi (7.33 mL, 11.73 mmol) and ethylmagnesium bromide (5.76 mL, 5.76 mmol) in 30 mL toluene was stirred at −30° C. for 30 min, then 5-bromo-1-methyl-1H-indazole (2.25 g, 10.66 mmol) in 5 mL THF was added. After stirring at −10° C. for 1 hour, anhydrous DMF (4.95 mL, 64.0 mmol) was added at −10° C. The reaction was allowed to warm to room temperature and stirred for 2 hours. The reaction was quenched with 1N HCl and concentrated in vacuo. The residue was diluted with water, extracted with DCM twice. The organic layers were combined, dried over Na2SO4 and concentrated. The crude product was purified by flash chromatography (hexane:EtOAc=10:1) to give the title compound as a white solid (1.37 g, 76%). 1H-NMR (400 MHz, DMSO-d6) δ ppm 10.02 (s, 1H), 8.41 (d, 1H), 8.31 (d, 1H), 7.86 (dd, 1H), 7.78 (d, 1H), 4.09 (s, 3H). LCMS (method A): [MH]+=161, tR=4.00 min.

Provenance & Evidence