反应详情

To a mixture of 5-bromo-7-fluoro-1H-indazole (9.3 g, 43.26 mmol) and DHP (4.36 g, 51.9 mmol) in dry dichloromethane (100 mL), was added PTSA (424 mg, 2.16 mmol) at room temperature. The resulting mixture was stirred overnight. Work-up: saturated aqueous NaHCO3 (30 mL) was slowly added to the reaction mixture. The organic layer was separated, dried over Na2SO4, and concentrated in vacuo. The residue was purified by column chromatography on silica gel (0˜10% EtOAc in petroleum ether) to give 5-bromo-7-fluoro-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole as a light yellow solid. (7.8 g). 1H NMR (300 MHz, CDCl3): δ 7.98 (s, 1H), 7.64 (s, 1H), 7.22 (dd, 1H), 5.84 (dd, 1H), 4.07-4.02 (m, 1H), 3.78-3.71 (m, 1H), 2.62-2.53 (m, 1H), 2.16-2.07 (m, 2H), 1.79-1.71 (m, 2H), 1.63-1.33 (m, 1H).

1. customThe organic layer was separated
2. dry with materialdried over Na2SO4
3. concentrationconcentrated in vacuo
4. customThe residue was purified by column chromatography on silica gel (0˜10% EtOAc in petroleum ether)