反应详情

H2SO4 (1.2 mL, 23.4 mmol, 1.0 eq.) was added to a solution of 3-bromopyridine-2-carboxylic acid (4.7 g, 23.4 mmol, 1.0 eq.) in MeOH (50 mL). The resulting solution was stirred for 14 hours while the temperature was maintained at reflux in an oil bath. The mixture was cooled to room temperature and concentrated under vacuum. The residue was dissolved in EtOAc (50 mL) and the pH was adjusted to 10 with Na2CO3 (5 mol/L). The resulting solution was extracted with EtOAc (100 mL). The organic layer was washed with water (1×100 mL) and saturated aqueous NaCl (2×100 mL), dried over anhydrous Na2SO4 and concentrated under vacuum. The residue was applied onto a silica gel column and eluted with EtOAc/PE (1:20) to yield 3-bromopyridine-2-carboxylic acid methyl ester (4.0 g) as a yellow liquid.

1. temperaturewas maintained
2. temperatureat reflux in an oil bath
3. concentrationconcentrated under vacuum
4. dissolutionThe residue was dissolved in EtOAc (50 mL)
5. extractionThe resulting solution was extracted with EtOAc (100 mL)
6. washThe organic layer was washed with water (1×100 mL) and saturated aqueous NaCl (2×100 mL)
7. dry with materialdried over anhydrous Na2SO4
8. concentrationconcentrated under vacuum
9. washeluted with EtOAc/PE (1:20)