反应详情

5 g of 1-(3,5-dichloro-pyrazin-2-yl)-ethanol obtained in step (i) were dissolved in dry DCM (100 ml) at RT in a reaction vessel containing a magnetic stirring bar and 80.7 ml Dess-Martin periodinane (1,1,1-tris(acetyloxy)-1,1-dihydro-1,2-benziodoxol-3-(1H)-one) solution (15% in DCM), and the mixture stirred for 30 min before the reaction was quenched with a saturated aqueous sodium bicarbonate solution (100 ml) and extracted with EtOAc (3×200 ml). The combined organic phases were dried over sodium sulfate, filtered and evaporated to afford the crude product as a brown oil. Purification by flash chromatography on silica gel using a mixture of EtOAc and heptane as the eluent afforded 1-(3,5-dichloro-pyrazin-2-yl)-ethanone as a colorless oil after evaporation of the solvents under reduced pressure. Yield: 1.9 g (38%).

1. additioncontaining a magnetic stirring bar
2. customwas quenched with a saturated aqueous sodium bicarbonate solution (100 ml)
3. extractionextracted with EtOAc (3×200 ml)
4. dry with materialThe combined organic phases were dried over sodium sulfate
5. filtrationfiltered
6. customevaporated
7. customto afford the crude product as a brown oil
8. customPurification by flash chromatography on silica gel using
9. additiona mixture of EtOAc and heptane as the eluent