反应详情

A solution of 5,6-dichloro-nicotinic acid (1.92 g, 10 mmol, Aldrich) and p-toluenesulfonic acid monohydrate (190 mg, 1.0 mmol, Aldrich) in methanol (5 mL, Aldrich) was heated at reflux for 25 h. The reaction mixture was cooled to room temperature, the solvent was removed in vacuo and the residue was dissolved in EtOAc (50 mL). The solution was washed with satd. NaHCO3 (20 mL) and brine (20 mL), dried over Na2SO4, and filtered. The filtrate was evaporated in vacuo and the residue was purified by silica gel column chromatography, eluting with 30% EtOAc/hexane to give the title compound as a white solid. MS ESI, pos. ion) m/e: 205 (M+1).

1. temperatureat reflux for 25 h
2. customthe solvent was removed in vacuo
3. dissolutionthe residue was dissolved in EtOAc (50 mL)
4. washThe solution was washed with satd
5. dry with materialNaHCO3 (20 mL) and brine (20 mL), dried over Na2SO4
6. filtrationfiltered
7. customThe filtrate was evaporated in vacuo
8. customthe residue was purified by silica gel column chromatography
9. washeluting with 30% EtOAc/hexane