反应详情

2',4'-Difluoro-2-hydroxypropiophenone (61 g) was dissolved in methylene chloride (500 ml), to which was added, under ice-cooling, p-toluene sulfonic acid.hydrate (1.0 g). To the mixture was added, under ice-cooling while stirring, 3,4-dihydro-2H-pyran (41.4 g) during 10 minutes. The mixture was stirred, under ice-cooling, for one hour, to which was added a 5% aqueous solution of sodium hydrogen carbonate (240 ml). The mixture was stirred for 10 minutes under ice-cooling. The methylene chloride layer was separated and dried over anhydrous magnesium sulfate, followed by distilling off the solvent. The residual oily product was purified by means of a silica gel column chromatography (hexane: ethyl acetate=5:1) to afford 2',4'-difluoro-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propiophenone (86.5 g) as a pale yellow oily product.

1. additionwas added, under ice-
2. temperaturecooling
3. additionTo the mixture was added, under ice-
4. temperaturecooling
5. stirringThe mixture was stirred, under ice-
6. temperaturecooling, for one hour, to which
7. stirringThe mixture was stirred for 10 minutes under ice-
8. temperaturecooling
9. customThe methylene chloride layer was separated
10. dry with materialdried over anhydrous magnesium sulfate
11. distillationby distilling off the solvent
12. customThe residual oily product was purified by means of a silica gel column chromatography (hexane: ethyl acetate=5:1)