反应详情

To a 0° C. stirred solution of 3.97 g (19.7 mmol) of ethyl 2-pyridyldifluoroacetate (prepared according to T. Taguchi, et al., Tetrahedron Lett. 1986, 27, 6103) in 40 mL of methanol was added 757 mg (20 mmol) of sodium borohydride in several portions. After stirring for 0.5 h, the cold bath was removed, and stirring continued another 0.5 h. The reaction was quenched with 2M HCl, and the solvents removed under reduced pressure. The residue was partitioned between ether and 10% Na2CO3, the aqueous layer extracted with several portions of ether and the combined organic layers washed with brine, dried over MgSO4 and the solvents removed to give 2.97 g of a yellow oil that was chromatographed on 65 g of fine SiO2 using 99:1 to 97:3 CH2—Cl2-CH3OH to give the title compound as an almost colorless solid:

1. customthe cold bath was removed
2. stirringstirring
3. waitcontinued another 0.5 h
4. customThe reaction was quenched with 2M HCl
5. customthe solvents removed under reduced pressure
6. customThe residue was partitioned between ether and 10% Na2CO3
7. extractionthe aqueous layer extracted with several portions of ether
8. washthe combined organic layers washed with brine
9. dry with materialdried over MgSO4
10. customthe solvents removed