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

Participants

Reaction Steps

To a solution of 5-bromo-3-(trifluoromethyl)-1H-indazole (500 mg, 1.887 mmol) in DCM (10 mL) was added 3,4-dihydro-2h-pyran (0.517 mL, 5.66 mmol) and p-toluenesulfonic acid monohydrate (35.9 mg, 0.189 mmol). The solution was stirred for 1 h. The solution was diluted with DCM, washed with saturated NaHCO3 and concentrated. The residue was purified by flash chromatography on silica gel with eluting with 10% EtOAc/Hexane to give 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-3-(trifluoromethyl)-1H-indazole as a colorless oil (610 mg, 93%). 1NMR: 400 MHz, CDCl3: δ ppm 1.69-1.75 (m, 7H), 2.12-2.17 (m, 2H), 2.48-2.51 (m, 1H), 3.61 (d, J=85.20 Hz, 3H), 3.72-3.78 (m, 2H), 3.87-3.99 (m, 3H), 4.56 (s, 1H), 5.77 (dd, J=4.00, 8.00 Hz, 1H), 7.52-7.60 (m, 2H), 7.96 (t, J=24.40 Hz, 1H).

Provenance & Evidence