反应详情

A round bottomed flask equipped with magnetic stirrer was loaded 8-[2,4-bis(methoxymethoxy)phenyl]-1,4-dioxaspiro[4.5]decane (1.30 g, 3.9 mmol) and methanol (15 ml). To the resulting stirred solution was added aqueous HCl (15 ml, 1M) in one portion. After stirring for one hr at room temperature the acid was quenched by adding saturated aqueous sodium bicarbonate solution (10 ml). After stirring vigorously for 10 min, the reaction mixture was transferred to a separating funnel and the phases separated and the aqueous phase was extracted with ethyl acetate (3×20 ml). The combined organic phases were washed with brine and the solvent evaporated. To the slightly wet crude product was added methanol (30 ml) and acidic ion exchange resin (4 g). The resulting mixture was heated under reflux, with stirring, for 5 hr. Filtering through a plug of Celite, washing with ethyl acetate, followed by removal of solvent in vacuo afforded an orange oil. Purification by flash column chromatography, (SiO2, ethyl acetate/petroleum ether, 1:1, v/v) furnished the title compound as a white powder (0.54 g, 68%). m/z (ES−) 411 (2M−1); δH (CD3OD) 1.94 (2H, ddd), 2.16-2.23 (2H, m), 2.41 (2H, dt), 2.62 (1H, t), 2.63 (1H, t), 6.24 (1H, dd), 6.31 (1H, d), 6.92 (1H, d).

1. customA round bottomed flask equipped with magnetic stirrer
2. stirringAfter stirring for one hr at room temperature the acid
3. customwas quenched
4. additionby adding saturated aqueous sodium bicarbonate solution (10 ml)
5. stirringAfter stirring vigorously for 10 min
6. customthe reaction mixture was transferred to a separating funnel
7. customthe phases separated
8. extractionthe aqueous phase was extracted with ethyl acetate (3×20 ml)
9. washThe combined organic phases were washed with brine
10. customthe solvent evaporated
11. additionTo the slightly wet crude product was added methanol (30 ml) and acidic ion exchange resin (4 g)
12. temperatureThe resulting mixture was heated
13. temperatureunder reflux
14. stirringwith stirring, for 5 hr
15. filtrationFiltering through a plug of Celite
16. washwashing with ethyl acetate
17. customfollowed by removal of solvent in vacuo
18. customafforded an orange oil
19. customPurification by flash column chromatography