Boron tribromide → 1-(3-amino-1H-indazol-5-yl)-3-(3-hydroxybenzyl)urea
Reaction equation
[NH2:1][C:2]1[C:10]2[C:5](=[CH:6][CH:7]=[C:8]([NH:11][C:12]([NH:14][CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[C:18]([O:22]C)[CH:17]=3)=[O:13])[CH:9]=2)[NH:4][N:3]=1.B(Br)(Br)Br>C(Cl)Cl>[NH2:1][C:2]1[C:10]2[C:5](=[CH:6][CH:7]=[C:8]([NH:11][C:12]([NH:14][CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[C:18]([OH:22])[CH:17]=3)=[O:13])[CH:9]=2)[NH:4][N:3]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
500 mg of 1-(3-amino-1H-indazol-5-yl)-3-(3-methoxybenzyl)urea are suspended in 10 ml of DCM, and 916 μl of BBr3 are added. After two days at RT, the mixture is carefully quenched using 1 ml of methanol and evaporated to dryness. Purification by silica-gel chromatography (eluent: DCM/MeOH 4:1) gives 400 mg of 1-(3-amino-1H-indazol-5-yl)-3-(3-hydroxybenzyl)urea (“A2) as a virtually colourless solid (84%); MS-FAB (M+H+)=298.