3,4-dihydro-2H-pyran → 1h-Indazole,5-bromo-3-(4-fluorophenyl)-1-(tetrahydro-2h-pyran-2-yl)-

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Reaction Steps

To a solution of 5-bromo-3-(4-fluorophenyl)-1H-indazole (8.00 g, 27.48 mmol) in dried tetrahydrofuran (80 mL) under nitrogen at ambient temperature was added 3,4-dihydro-2H-pyran (5.78 g, 68.7 mmol) and p-toluenesulfonic acid monohydrate (1.00 g, 5.26 mmol). The reaction mixture was stirred at room temperature for 24 hours. It was quenched with dichloromethane and washed with 5% sodium carbonate and brine. The dichloromethane layer was dried over magnesium sulfate and concentrated. Crystallization from diethyl ether and hexane provided the title compound (8.47 g, 82% yield). 1H NMR (CDCl3) δ 8.07 (t, 1H), 7.86–7.91 (m, 2H), 7.47–7.55 (m, 2H), 7.16–7.26 (m, 2H), 5.74 (dd, 1H), 4.05 (m, 1H), 3.76 (m, 1H), 2.60 (m, 1H), 2.08–2.21 (m, 2H), 1.66–1.83 (m, 3H); ES-MS (m/z) 377 [M+3]+, 375 [M+1]+.

Provenance & Evidence