反应详情

A mixture of 2 g of oily sodium hydride (60%) and 90 ml of dimethyl sulfoxide was stirred for 1 hour at 55°-60° C. and then allowed to cool to room temperature. To the mixture was added dropwise a mixture of 11 g of (4-carboxybutyl)triphenylphosphonium bromide and 25 ml of dimethyl sulfoxide at room temperature. Thereafter, the mixture was stirred for 30 minutes at room temperature and then to the reaction mixture was added dropwise a mixture of 8 g of 3,4-dibenzyloxybenzaldehyde and 30 ml of dimethyl sulfoxide. After further stirring the mixture for one hour at room temperature, 5 g of dry ice was added to the reaction mixture and after further adding thereto 250 ml of water and 50 ml of an aqueous 10% hydrochloric acid solution, the product was extracted with 300 ml of ether. The extract was washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to provide a sticky product. The product was applied to silica gel (150 ml) column chromatography and eluted with a mixture of n-hexane and ether (1:1) to provide 8.5 g of 6-(3,4-dibenzyloxyphenyl)-5-hexenoic acid. The product was dissolved in 30 ml of ethanol and catalytically reduced using 1 g of 10% palladium-carbon as a catalyst until the absorption of hydrogen stopped. Then, the catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to provide 3.8 g of 6-(3,4-dihydroxyphenyl)hexanoic acid. Melting point 109° C. ##STR53##

1. additionTo the mixture was added dropwise
2. stirringThereafter, the mixture was stirred for 30 minutes at room temperature
3. additionto the reaction mixture was added dropwise
4. stirringAfter further stirring the mixture for one hour at room temperature
5. additionafter further adding
6. extraction250 ml of water and 50 ml of an aqueous 10% hydrochloric acid solution, the product was extracted with 300 ml of ether
7. washThe extract was washed with water
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationconcentrated under reduced pressure
10. customto provide a sticky product
11. washeluted with a mixture of n-hexane and ether (1:1)