反应详情

Under a nitrogen stream, to methyl 2-(3-ethoxycarbonyl-2-oxo-propylsulfanyl)-benzoate (8.02 g, 27.1 mmol) was added polyphosphoric acid (25 g) at room temperature, and the resultant solution was stirred for 1 hour at 80° C. Under ice-cooling, to the solution was added water, and the resultant mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate. Solvent was then removed by distillation under reduced pressure. The resulting residue was purified by silica gel column chromatography (developing solution=ethyl acetate:n-hexane (1:3)), to thereby obtain the titled compound (2.77 g, 37%).

1. temperatureUnder ice-cooling, to the solution
2. extractionthe resultant mixture was extracted with ethyl acetate
3. washThe organic layer was washed with saturated aqueous sodium bicarbonate
4. dry with materialdried over anhydrous magnesium sulfate
5. customSolvent was then removed by distillation under reduced pressure
6. customThe resulting residue was purified by silica gel column chromatography (developing solution=ethyl acetate:n-hexane (1:3))