p-Toluenesulfonic acid → 4-Bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole

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Reaction Steps

A solution of 4-bromo-1H-indazole (1.82 g, 9.24 mmol), 3,4-dihydro-2H-pyran (1.55 g, 18.48 mmol) and toluene-4-sulfonic acid (0.26 g, 1.39 mmol) in anhydrous tetrahydrofuran (40 mL) was heated at 80° C. overnight under nitrogen. The solvent was removed under reduced pressure and the residue was purified on silica gel column (3% ethyl acetate in petroleum ether) to give the title compound (2.13 g, 81% yield) as a yellow solid. MS (ESI): m/z 280.9 [M+1]+.

Provenance & Evidence