反应详情

A mixture of 3-aminopyridine-2-carboxylic acid (6.4 g, 46.3 mmol) in 26 mL of EtOH and 8 mL of concentrated sulfuric acid is heated to reflux for 2 days. After cooling, the mixture is concentrated to about 15-20 mL and poured into 20 g of ice. The mixture is basified to pH 8-9 with concentrated NH4OH while cooling in an ice bath. The resulting brown precipitate is filtered off, and the filtrate is extracted with ether (4×60 mL). The combined ether extracts are washed with brine (4×60 mL), dried (Na2SO4), filtered, and evaporated to give a yellow/brown solid. This solid is combined with that from the above filtration and the whole is triturated with cold ether to give the title compound as a light brown solid. 1H NMR (400 MHz, CDCl3) δ 8.08 (1H, m), 7.21 (1H, m), 7.03 (1H, m), 5.74 (2H, bs), 4.44 (2H, q, J 7.2, 6.9), 1.45 (3H, t, J 6.9).

1. temperatureis heated
2. temperatureto reflux for 2 days
3. temperatureAfter cooling
4. concentrationthe mixture is concentrated to about 15-20 mL
5. additionpoured into 20 g of ice
6. temperaturewhile cooling in an ice bath
7. filtrationThe resulting brown precipitate is filtered off
8. extractionthe filtrate is extracted with ether (4×60 mL)
9. washThe combined ether extracts are washed with brine (4×60 mL)
10. dry with materialdried (Na2SO4)
11. filtrationfiltered
12. customevaporated
13. customto give a yellow/brown solid
14. filtrationfrom the above filtration
15. customthe whole is triturated with cold ether