反应详情

温度

0 °C

An aqueous solution (5.1 mL) of sodium nitrite (4.5 mmol, 311 mg) was cooled in an ice bath and added to a mixture of 694 mg (4.5 mmol) of 4-amino-benzoic acid methyl ester in 2.36 N aq. HCl (7.5 mL) at 0° C. The mixture was stirred at 0° C. for 30 min, and the reaction mixture was added to a mixture of 795 mg (4.5 mmol) of (1H-imidazol-4-yl)-acetic acid methyl ester hydrochloride in saturated aqueous sodium tetraborate solution (150 mL). The mixture was stirred at 0° C. for 1.5 h and slowly warmed up to room temperature. The 4-(4-Methoxycarbonylmethyl-1H-imidazol-2-ylazo)-benzoic acid methyl ester was obtained after filtering and washing with water in a quantitative yield. LCMS: 303 (M+1)+.

1. stirringThe mixture was stirred at 0° C. for 1.5 h
2. temperatureslowly warmed up to room temperature