Boron tribromide → 4-bromo-1-(2,2-dimethylpropyl)-1H-1,2,3-benzotriazol-5-ol
Reaction equation
[Br:1][C:2]1[C:10]2[N:9]=[N:8][N:7]([CH2:11][C:12]([CH3:15])([CH3:14])[CH3:13])[C:6]=2[CH:5]=[CH:4][C:3]=1[O:16]C.B(Br)(Br)Br>C(Cl)Cl>[Br:1][C:2]1[C:10]2[N:9]=[N:8][N:7]([CH2:11][C:12]([CH3:14])([CH3:13])[CH3:15])[C:6]=2[CH:5]=[CH:4][C:3]=1[OH:16]Participants
4
Procedure
To a solution of 4-bromo-1-(2,2-dimethylpropyl)-5-methoxy-1H-1,2,3-benzotriazole (Example 1-1) (8.97 g, 30.1 mmol, 1.0 equiv.) in DCM (150 ml) at 0° C., was added slowly 1 M solution of BBr3 (60.2 ml, 60.2 mmol, 2.0 equiv.) in DCM. The reaction mixture was allowed to warm up to room temperature overnight. LCMS showed completion. The reaction mixture was quenched with water, neutralized to pH=7, then extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered and concentrated to give 4-bromo-1-(2,2-dimethylpropyl)-1H-1,2,3-benzotriazol-5-ol (Example 1-2). 1H NMR (500 MHz, CDCl3) δ 7.36 (d, 1H, J=9.0 Hz), 7.24 (d, 1H, J=9.0 Hz), 4.37 (s, 2H), 1.04 (s, 9H) ppm. LRMS m/z (M+H) 283.9 and 285.9 (intensity ratio ˜1:1) found, 284.0 and 286.0 required.