General procedure for the synthesis of 5-bromo-1-methyl-1H-benzo[d][1,2,3]triazole from 4-bromo-N1-methylbenzene-1,2-diamine: 5-bromo-1-methyl-7H-benzo[2 (1.52 g, 22 mmol) was dissolved in water (5 ml) at 0 °C. The resulting solution was stirred at 0-10°C for 4 h. The pH was adjusted to 8 with potassium hydroxide (3N) and extracted with dichloromethane (2 x 200 ml). The organic layers were combined and concentrated in vacuum to give the residue. The residue was purified by silica gel chromatography (eluent: petroleum ether solution of 50% dichloromethane) to afford 5-bromo-1-methyl-1H-benzo[d][1,2,3]triazole as a red solid (1.5 g, 31% yield).LC/MS (ESI, m/z): [M + H]+ 213.1.1.1H-NMR (300 MHz, CDCl3) δ 8.24-8.25 (m, 1H), 7.60-7.63 (m, 1H), 7.42-7.46 (m, 1H), 4.32 (d, J = 5.4 Hz, 3H).