反应详情

Take 2-(2,6-Dichloro-phenyl)-3H-benzoimidazole-5-carboxylic acid methyl ester (1.00 g, 3.11 mmol) up in MeOH (6 mL) and 1 N NaOH (6 mL) and stir for 24 hr. Add additional 1 N NaOH (6 mL) and stir for an additional 30 hr. Concentrate under reduced pressure. Neutralize the concentrate at 0° C. by the dropwise addition of 1 N HCl (12 mL). Collect the resulting precipitate and wash with water followed by Et2O. Dry the solid in a vac oven to afford the desired acid as a tan solid: 1H NMR (400 MHz, DMSO-d6) δ ppm 7.60-7.67 (m, 1H) 7.68 (s, 2H) 7.70 (d, J=2.15 Hz, 1H) 7.89 (d, J=8.46 Hz, 1H) 8.24 (br. s., 1H) 12.83 (br. s., 1H) 13.23 (br. s., 1H); (M+H)+ 306.9.

1. stirringstir for an additional 30 hr
2. concentrationConcentrate under reduced pressure
3. concentrationconcentrate at 0° C. by the dropwise addition of 1 N HCl (12 mL)
4. customCollect the resulting precipitate
5. washwash with water
6. customDry the solid in a vac oven