反应详情

3.07 g (7.44 mM) of 3-(3,4-dimethoxyphenyl)-4,4-diethoxy-2-ethoxycarbonylbutyric acid ethyl ester and 3.41 g of potassium hydroxide were heated at reflux for 4 hours in 40 ml of ethanol. The solution was poured to water, was acidified with concentrated hydrochloric acid, and was extracted with diethyl ether. The organic extract was dried over anhydrous magnesium sulfate and the solvent was evaporated in vacuo to obtain 1.98 g of brown oily 3-(3,4-dimethoxyphenyl)-4,4-diethoxybutyric acid. 1.98 g of the brown oily product thus obtained and 0.90 ml of hydrazine hydrate were added to a mixed solution of 8.3 ml of acetic acid and 6.3 ml of water. The solution was heated at reflux for 5 hours, poured to an aqueous sodium hydrogencarbonate solution, extracted with methylene chloride, and dried. The solvent was evaporated in vacuo to obtain a yellow solid residue. The residue was purified by flash chromatography (SiO2: eluted with a gradient of 60% ethyl acetate/hexane to 70% ethyl acetate/hexane). The solvent was evaporated in vacuo and the resultant product was dried to obtain 0.92 g of a light yellow solid of the above-described compound (yield 53.0%).

1. extractionwas extracted with diethyl ether
2. extractionThe organic extract
3. dry with materialwas dried over anhydrous magnesium sulfate
4. customthe solvent was evaporated in vacuo