反应详情

温度

140 °C

Compound (9) (9.45 g, 39.3 mmoles) and propionic acid were dissolved in newly distilled ethyl ortho-acetate (51.0 g, 314 mmoles). The solution was stirred at 140° C. for 6 hours while distilling off ethanol. Ethyl ortho-acetate was removed from the resulting reaction mixture, and the residue was concentrated. After cooling, the residue was diluted with ether. The ether solution was washed with a saturated aqueous solution of sodium hydrogencarbonate and then with an aqueous solution of sodium chloride, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (200 g of silica gel; n-hexane/ethyl acetate) to give a compound (10) as a mixture of the (1S,3S)-isomer and (1R,3S)-isomer (11.7 g, 37.7 mmoles, yield 96%).

1. distillationwhile distilling off ethanol
2. customEthyl ortho-acetate was removed from the resulting reaction mixture
3. concentrationthe residue was concentrated
4. temperatureAfter cooling
5. additionthe residue was diluted with ether
6. washThe ether solution was washed with a saturated aqueous solution of sodium hydrogencarbonate
7. dry with materialwith an aqueous solution of sodium chloride, dried over magnesium sulfate
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by column chromatography (200 g of silica gel; n-hexane/ethyl acetate)