3,4-dihydro-2H-pyran → 4-Bromomethyl-1-(tetrahydro-pyran-2-yl)-1H-indazole

Participants

Reaction Steps

A solution of 4-bromomethyl-1H-indazole (2.0 g, 9.476 mmol), 3,4-dihyro-2H-pyran (4.0 mL, 43.84 mmol), p-toluenesulfonic acid monohydrate (2.0 g, 10.51 mmol) and anhydrous THF (20 mL) was heated at 60° C. for 1 h. The reaction mixture was cooled, added to aqueous saturated sodium carbonate solution (50 mL) and extracted with ethyl acetate (200 mL). The organic layer was washed with brine (50 mL), dried over MgSO4, filtered and concentrated under reduced pressure. The resulting crude compound was purified by flash chromatography (20% EtOAc in hexanes) to give 4-bromomethyl-1-(tetrahydro-pyran-2-yl)-1H-indazole (2.43 g, 86.9%) as an off white solid. MS m/e 296.2 (M+H+).

Provenance & Evidence