Hydrochloric Acid → 1-methyl-1H-1,2,3-benzotriazole-5-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of the diamine 280 (1.08 g; 6.48 mmol) (or any other o-arylenediamine) in water (25 mL) at 0° C., concentrated HCl (5.4 mL) was added drop wise followed by slow addition of a solution of NaNO2 (643 mg; 9.3 mmol) in water (10 mL). The reaction mixture was stirred at 0° C. for 2 h and then was allowed to warm up to 10° C. over 4 h; neutralized with a solution of KOH (5.6 g) in water (30 mL) (final pH=6); concentrated and purified by preparative HPLC in reverse phase mode (column aquasil C-18, elution 5% to 95% MeOH in water), to afford the title compound 284 (211 mg; 18% yield). 1H NMR: (400.2 MHz, DMSO) δ (ppm): 8.35 (s; 1H); 8.08 (dd, J=1.4, 8.6 Hz; 1H); 7.75 (d, J=1.4 Hz; 1H); 4.03 (s, 3H). MS: calc: 177.1; found: 178.1 (M+H).

Provenance & Evidence