乙基 3-(二甲氨基)-3-氧代丙酸乙酯

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A 8.1 g (44.5 mmol) of syringaldehyde, 7.2 g (44.4 mmol) of ethyl a-dimethylcarbamoylacetate and 6.6 ml (66.7 mmol) of piperidine in 150 ml of ethanol solution was stirred at 110° C. for about 12 hours. The mixture was concentrated under reduced pressure and purified by silica gel column chromatography (methanol/chloroform=2-4%). An oily product thus obtained was dissolved in 50 ml of tetrahydrofuran. To the solution was added an aqueous potassium hydroxide solution (4.3 g/10 ml), and the solution was stirred at room temperature for 15 hours. A 50 ml of ethyl acetate was added to the solution. The mixture was extracted with 100 ml of water. The aqueous layer was acidified with conc. hydrochloric acid and extracted with 120 ml of methylene chloride. The organic layer was dried over anhydrous magnesium sulfate and evaporated under reduced pressure to give 4.6 g (yield 35%) of objective α-dimethylcarbamoyl-3,5-dimethoxy-4-hydroxycinnamic acid. The mixture was concentrated under reduced pressure purified by silica gel column chromatography (methanol/chloroform=2-4%) An oily product thus obtained The mixture was extracted with 100 ml of water extracted with 120 ml of methylene chloride The organic layer was dried over anhydrous magnesium sulfate evaporated under reduced pressure