3,4-dihydro-2H-pyran → 5-bromo-1-(oxan-2-yl)-1H-indazole

Participants

Reaction Steps

3,4-dihydro-2H-pyran (0.84 ml, 9.21 mmol) and pyridinium p-toluenesulfonate (202 mg, 0.804 mmol) were added to a solution of 5-bromo-1H-indazole (790 mg, 4.01 mmol) in methylene chloride (15 ml) at room temperature, and the resulting mixture was refluxed for 6 hours. Then, the reaction solution was poured into a saturated aqueous sodium hydrogencarbonate solution and extracted with chloroform. The organic layer was washed with a saturated aqueous sodium chloride solution and then dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate=93/7) to obtain 5-bromo-1-tetrahydro-2H-pyran-2-yl-1H-indazole (1.06 g, 94%).

Provenance & Evidence