反应详情

Sodium hydride (oily, 60%, 4.60 g) was added little by little to a solution of 2-(1,3-dioxolan-2-yl)ethyltriphenylphosphonium bromide (51.0 g) in N,N-dimethylformamide (200 ml) at 0° C. After stirring for 15 minutes, 4-isopropoxybenzaldehyde (18.0 g) was added, and the mixture was stirred at 80 to 85° C. for 5 hours. Water was added to the reaction mixture, acidified with 2N hydrochloric acid, and extracted with ether. The ether layer was washed with water and dried over magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was subjected to column chromatography on silica gel. An oil of the intermediate which was obtained from the fractions eluted with ethyl acetate-hexane (1:4, v/v) was dissolved in ethanol (250 ml), and 5% palladium-carbon (5.00 g) was added. The mixture was subjected to catalytic hydrogenation at 1 atm and room temperature. The catalyst was filtered off, and the filtrate was concentrated under reduced pressure. The residue was subjected to column chromatography on silica gel. The fractions eluted with ethyl acetate-hexane (1:5, v/v) to give 2-[3-(4-isopropoxyphenyl)propyl]-1,3-dioxolane (6.70 g, 24%) as an oil.

1. stirringthe mixture was stirred at 80 to 85° C. for 5 hours
2. extractionextracted with ether
3. washThe ether layer was washed with water
4. dry with materialdried over magnesium sulfate
5. customthe solvent was evaporated under reduced pressure
6. customAn oil of the intermediate which was obtained from the fractions
7. washeluted with ethyl acetate-hexane (1:4, v/v)
8. dissolutionwas dissolved in ethanol (250 ml)
9. addition5% palladium-carbon (5.00 g) was added
10. customwas subjected to catalytic hydrogenation at 1 atm and room temperature
11. filtrationThe catalyst was filtered off
12. concentrationthe filtrate was concentrated under reduced pressure
13. washThe fractions eluted with ethyl acetate-hexane (1:5