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 toluene (30 mL) was stirred at −30° C. for 30 min, and then a solution of 5-bromo-1-methyl-1H-indazole (2.25 g, 10.66 mmol) in THF (5 mL) was added. After 1 h, anhydrous DMF (4.95 mL, 64.0 mmol) was added at −10° C. The reaction mixture was allowed to warm to rt and stirred for 2 h. The reaction was quenched with saturated aqueous NH4Cl solution 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 ppnn 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