反应详情

5-Propyl-1H-imidazole-4-carboxylic acid ethyl ester 2 (2.00 g; 11.0 mmol) and concentrated aqueous HCl (40 mL) were combined and heated to reflux with stirring for 24 h. After cooling to rt, the light tan solution was diluted with water (100 mL) and extracted with EtOAc. The aqueous layer was then evaporated under reduced pressure. The residue was dissolved in 2-propanol (20 mL) and cooled to −78 C. Upon addition of Et2O, a white precipitate formed. This material was collected by filtration and dried under vacuum to afford 2.10 g (100%) of 3. 1H NMR (DMSO-d6): δ 0.87 (t, 3H), 1.69 (m, 2H), 2.92 (t, 2H), 9.17 (s, 1H); 13C NMR (DMSO-d6): δ 13.9, 22.4, 26.4, 120.9, 135.7, 140.0, 160.7; Anal. calcd for C7H11ClN2O20.66(C3H9O)0.33(H2O): C, 45.67; H, 7.24; N, 11.84; Cl, 14.98; found: C, 45.27; H, 7.17; N, 11.86; Cl, 14.68.

1. temperatureheated
2. temperatureto reflux
3. extractionextracted with EtOAc
4. customThe aqueous layer was then evaporated under reduced pressure
5. dissolutionThe residue was dissolved in 2-propanol (20 mL)
6. temperaturecooled to −78 C
7. additionUpon addition of Et2O
8. customa white precipitate formed
9. filtrationThis material was collected by filtration
10. customdried under vacuum