反应详情

3-(3,4-dimethoxyphenyl)-4,4-diethoxy-2-ethoxycarbonyl butyric acid ethyl ester (3.07 g, 7.44 mM) and potassium hydroxide (3.41 g) were refluxed in ethanol (40 ml) for 4 hours. To this solution water was poured, acidified with concentrated hydrochloric acid, and extracted with diethylether. The organic extract was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to obtain a brown oil of 3-(3,4-dimethoxyphenyl)-4,4-diethoxy butyric acid (1.98 g). The brown oil (1.98 g) thus obtained and hydrazine hydrate (0.90 ml) were added to a mixture of acetic acid (8.3 ml) and water (6.3 ml), refluxed for 5 hours, poured into an aqueous solution of sodium bicarbonate, extracted with methylene chloride, dried, and the solvent was evaporated under reduced pressure to obtain a yellow solid residue. The residue was purified with flash chromatography (SiO2: eluted with a gradient of 60% ethyl acetate/hexane to 70% ethyl acetate/hexane). The solvent was evaporated under reduced pressure, and the residue was dried to obtain the pale yellow solid of title compound (0.92 g, yield 53.0%).

1. extractionextracted with diethylether
2. extractionThe organic extract
3. dry with materialwas dried over anhydrous magnesium sulfate
4. customthe solvent was evaporated under reduced pressure