反应详情

温度

5 °C

Ethyl pyruvate (1,500 g) is added in the course of 2 hours, while the temperature is maintained at approximately 5° C., to N,N-dimethylformamide diethyl acetal (2,100 g) cooled to a temperature in the region of 5° C. The mixture is then stirred for 3 hours at a temperature in the region of 20° C. The reaction ethanol is evaporated off to dryness and the residue obtained is pounded with diethyl ether (12 liters) and charcoal 3S (30 g) and then filtered on supercel. The filtrate is taken up with water (500 cc), and the organic phase is decanted and the aqueous phase is extracted with dichloromethane (3×2000 cc). The organic phases are mixed, dried over sodium sulphate, filtered and concentrated to dryness at 40° C. under reduced pressure (20 mm Hg; 2.7 kPa). The oil obtained is purified by distillation (b.p.0.1 mm Hg 146°-149° C.). Ethyl 4-dimethylamino-2-oxo-3-butenoate (695 g) is thereby obtained, and is used in the crude state in the subsequent syntheses.

1. customis evaporated off to dryness
2. customthe residue obtained
3. filtrationfiltered on supercel
4. customthe organic phase is decanted
5. extractionthe aqueous phase is extracted with dichloromethane (3×2000 cc)
6. additionThe organic phases are mixed
7. dry with materialdried over sodium sulphate
8. filtrationfiltered
9. concentrationconcentrated to dryness at 40° C. under reduced pressure (20 mm Hg; 2.7 kPa)
10. customThe oil obtained
11. distillationis purified by distillation (b.p.0.1 mm Hg 146°-149° C.)