反应详情

To 150 mL of conc. H2SO4 was added 42.96 g (334 mmol) of 2-amino-5-chloropyridine in portions with stirring and cooling (ice-water bath). To the resulting solution was added dropwise 22.5 mL of 69-71% HNO3 (355 mmol) at 50° C. (at such a rate that maintain the temperature within 50°-55° C.) over 1 h. The resulting mixture was stirred at 60° C. for 3 h, poured into ice-water (about 1,500 mL) with stirring, then basified to pH 9 by the addition of 40% aq NaOH with stirring and cooling. The precipitate was filtered, washed with water (6×50 mL), and dried to give 32.47 g (56%) of 2 as a yellow powder, mp 190°-191° C. (lit. 191°-2° C. (Israel, M. & Day, A. R., J. Org. Chem. 24:1455-1460 (1959))). 1H NMR (DMSO-d6), 8.044-8.055 (m, 3H), 8.054 (d, 1H, J=3.9).

1. temperaturethat maintain the temperature within 50°-55° C.) over 1 h
2. stirringThe resulting mixture was stirred at 60° C. for 3 h
3. stirringwith stirring
4. stirringwith stirring
5. temperaturecooling
6. filtrationThe precipitate was filtered
7. washwashed with water (6×50 mL)
8. customdried