反应详情

温度

80 °C

A mixture of crude 5-bromo-N2-[3-(pyridin-3-yl)phenyl]pyridine-2,3-diamine and 98% formic acid was heated at 80° C. for 3 hours. The reaction was cooled, evaporated to dryness, the residue suspended in water and made basic by the cautious addition of solid sodium hydrogen carbonate. This was then extracted with ethyl acetate, the organics dried over anhydrous sodium sulphate, filtered and pre-adsorbed on to silica. Purification by silica gel chromatography eluting with dichloromethane/methanol/0.88 NH3 (95:4.5:0.5) furnished 6-bromo-3-[3-(pyridin-3-yl)phenyl]-3H-imidazo[4,5-b]pyridine as a tan solid (3.1 g, 89% over 2 steps), m.p. 212-213° C. (Found C, 57.24; H, 2.98; N, 15.57. C17H11BrN4. 0.25H2O requires C, 57.40; H, 3.26; N, 15.75); δH (400 MHz, d6-DMSO) 7.55 (1H, dd, J 5 and 5), 7.76 (1H, t, J 8), 7.86 (1H, d, J 8), 8.04 (1H, d, J 8), 8.22 (1H, d, J 8), 8.27 (1H, s), 8.56 (2H, d, J 6), 8.64 (1H, d, J 5), 9.04 (1H, s), 9.11 (1H, s); m/z (ES+) 351 and 353 (M++H).

1. temperatureThe reaction was cooled
2. customevaporated to dryness
3. additionmade basic by the cautious addition of solid sodium hydrogen carbonate
4. extractionThis was then extracted with ethyl acetate
5. dry with materialthe organics dried over anhydrous sodium sulphate
6. filtrationfiltered and pre-adsorbed on to silica
7. customPurification by silica gel chromatography
8. washeluting with dichloromethane/methanol/0.88 NH3 (95:4.5:0.5)