反应详情

6-(4-Bromo-2-methyl-phenylamino)-7-fluoro-3H-benzoimidazole-5-carboxylic acid hydrazide 20a (0.041 g, 0.109 mmol) is suspended in 1,4-dioxane (1.5 mL) and 36 μL of a 3 M solution of cyanogen bromide in methylene chloride is added. NaHCO3 (9 mg, 0.109 mmol) in water (1.5 mL) is then added. After 16 hours, the reaction mixture is diluted with water and brine and extracted with THF. The combined organic extracts are dried (Na2SO4) and concentrated under reduced pressure. Purification by FCC eluted with 98:2 ethyl acetate:MeOH provides 24 mg (55%) of pure desired product as a yellow solid: LC/MS ESI (+) m/z 403, 405 (M+Br pattern) detected; 1H-NMR (400 MHz, DMSO-d6) δ 12.97 (s, 1H), 8.42 (s, 1H), 7.94 (s, 1H), 7.74 (s, 1H), 7.36 (s, 2H), 7.33 (d, 1H), 7.15 (d, 1H), 6.40 (bs, 1H), 2.34 (s, 3H).

1. extractionextracted with THF
2. dry with materialThe combined organic extracts are dried (Na2SO4)
3. concentrationconcentrated under reduced pressure
4. customPurification by FCC
5. washeluted with 98:2 ethyl acetate