Dimethylformamide → 6-Fluoro-1-tetrahydropyran-2-yl-indazole-4-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of n-butyllithium (13 mL, 21.4 mmol, 1.6 M in hexanes) in THF (60 mL) at −78° C. was added dropwise over 30 min a solution of 4-bromo-6-fluoro-1-tetrahydropyran-2-yl-indazole (4.00 g, 13.4 mmol) in THF (20 mL). The reaction was warmed to −40° C. for 5 min, re-cooled to −78° C., and DMF (4.2 mL, 53.5 mmol) was added. The reaction mixture was allowed to warm to RT and stirred for 2 h. The reaction was then quenched with a satd. aq. NH4Cl at 0° C. EtOAc was added and the layers were separated, and the aqueous layer was extracted once with EtOAc. The combined extracts were dried (Na2SO4), filtered and concentrated in vacuo. The crude mixture was purified by SiO2 chromatography to afford 6-fluoro-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-4-carbaldehyde (2.18 g, 66%), as a white solid. MS (ESI) m/z: 249.3 [M+1]+.

Provenance & Evidence