The general procedure for the synthesis of 5-methoxy-1H-benzo[d][1,2,3]triazole from 4-methoxy-o-phenylenediamine hydrochloride was as follows: tert-butyl nitrite (1.35 mL) was added slowly and dropwise to a solution of acetonitrile (20 mL) of 1,2-diamino-4-methoxybenzene hydrochloride (2 g) at 0 °C. The reaction mixture was stirred at room temperature for 4 hours and then concentrated under reduced pressure. The resulting solid residue was dissolved in water and neutralized to pH neutral with saturated sodium bicarbonate solution. Subsequently, extraction was carried out with ethyl acetate and the organic phase was washed with saturated brine and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to give 5-methoxy-1H-benzo[d][1,2,3]triazole as an off-white solid (1.2 g, 85% yield). Mass spectrum (electrospray ionization): m/z [M + H]+ = 150.
