反应详情

Concentrated H2SO4 (20 mL, 360 mmole) was added dropwise over 5 minutes to a suspension of 2-aminonicotinic acid (25 g, 181 mmole) in MeOH (400 mL), and the mixture was heated at reflux; a homogeneous solution formed within 5 min. After 72 h, the reaction was cooled to room temperature and concentrated under vacuum. The residue was basified with 1.0 N Na2CO3 (500 mL) (Gas evolution!) and extracted with EtOAc (500 mL). The organic layer was washed with brine, dried (Na2SO4), and concentrated to dryness to give the title compound (19.6 g, 71%) as a white solid: 1H NMR (400 MHz, CDCl3) δ 8.22 (dd, 1 H), 8.13 (dd, 1 H), 6.63 (dd, 1 H), 6.30 (br s, 2 H), 3.89 (s, 3 H).

1. temperaturethe mixture was heated
2. temperatureat reflux
3. customa homogeneous solution formed within 5 min
4. concentrationconcentrated under vacuum
5. extractionextracted with EtOAc (500 mL)
6. washThe organic layer was washed with brine
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated to dryness