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

Reaction equation

[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][NH:6]2.[O:11]1[CH:16]=[CH:15][CH2:14][CH2:13][CH2:12]1.C1(C)C=CC(S(O)(=O)=O)=CC=1>O1CCCC1>[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][N:6]2[CH:12]1[CH2:13][CH2:14][CH2:15][CH2:16][O:11]1

Participants

Procedure

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]+.