反应详情

To a THF (20 ml) solution of pyridine-2,3-dicarboxylic acid anhydride (1.92 g, 12.9 mmol) was added a THF solution of 2-benzyloxy-4-methoxyphenyllithium (10 ml), which was prepared from 2-benzyloxy-4-methoxyphenyl bromide (3.77 g, 12.9 mmol) and BuLi (1.6M hexane solution, 8.85 ml, 14.2 mmol) at -78° C., at -78° C. over a period of 5 min. The temperature of the mixture was raised to room temperature and the mixture was additionally stirred at the same temperature for 2 h. The reaction mixture was concentrated under reduced pressure and the residue was partitioned between 1N HCl and AcOEt. The organic layer was washed with 1N HCl dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was dissolved in 1N NaOH and the solution was washed with AcOEt and chloroform. The aqueous layer was acidified with conc. HCl and extracted with AcOEt. The organic layer was washed with 1N HCl and brine, dried over Na2SO4, filtered, and concentrated under reduced pressure. The residual solid was recrystallized from is chloroform-ether to give 2-(2-benzyloxy-4-methoxyphenylcarbonyl)-3-pyridine carboxylic acid (2,03 g) as a colorless solid.

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. customthe residue was partitioned between 1N HCl and AcOEt
3. washThe organic layer was washed with 1N HCl
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. dissolutionThe residue was dissolved in 1N NaOH
8. washthe solution was washed with AcOEt and chloroform
9. extractionextracted with AcOEt
10. washThe organic layer was washed with 1N HCl and brine
11. dry with materialdried over Na2SO4
12. filtrationfiltered
13. concentrationconcentrated under reduced pressure
14. customThe residual solid was recrystallized