反应详情

A mixture of 2-chloro-5-nitroisonicotinic acid (Intermediate 208) and 16 ml triethylorthoacetate in 100 ml toluene was heated at reflux for 2 h. The mixture as stirred with 1N HCl for 30 min before being partitioned between EtOAc and water. The EtOAc was separated, washed with water and brine, dried (MgSO4) and concentrated. Chromatographed on silica gel (100% hexanes with gradient elution to 100% CH2Cl2 to give product as an oil. MS (ES) (MH+): 231 for C8H7ClN2O4; NMR (d6-DMSO): 1.3 (t, 3H), 4.4 (m, 2H), 8.1 (s, 1H), 9.2 (s, 1H).

1. temperaturewas heated
2. temperatureat reflux for 2 h
3. custombefore being partitioned between EtOAc and water
4. customThe EtOAc was separated
5. washwashed with water and brine
6. dry with materialdried (MgSO4)
7. concentrationconcentrated
8. customChromatographed on silica gel (100% hexanes
9. washwith gradient elution to 100% CH2Cl2
10. customto give product as an oil