Dimethylformamide → 6-Fluoro-1-methyl-1H-indazole-5-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A 2 M solution of n-butyl magnesium chloride in THF (4.8 mL, 9.57 mmol) was added to toluene (34 mL) under nitrogen and cooled to −10° C. To this was added a 1.3 M solution of n-butyl lithium in hexane (12.2 mL, 19.5 mmol) and after 1 h, the RM was cooled to −30° C. To the RM was then added a solution of 5-bromo-6-fluoro-1-methyl-1H-indazole (vii) (4 g, 17.73 mmol) in THF (17 mL) and the reaction was warmed up to −10° C. After 1 h, DMF (8.23 mL, 106 mmol) was added and the RM was stirred at −10° C. for another 1 h. The reaction was quenched using 2 N HCl and was allowed to warm up to room temperature. After 30 min, the RM was basified with saturated aqueous NaHCO3 solution and then extracted with EtOAc. The organic phase was washed with brine, dried over Na2SO4 and evaporated under vacuo. The residue was triturated with Et2O. The precipitate formed was filtered off to give a yellow solid identified as the desired aldehyde (tR 0.79 min (conditions 2), MH+=179).

Provenance & Evidence