反应详情

温度

0 °C

Meldrum's acid (80 g, 555 mmol) was dissolved in 600 mL of CH2Cl2 and cooled to 0° C. Freshly distilled pyridine (87.8 g, 1.11 mol) was added to the CH2Cl2 solution and then iso-butyryl chloride (65.0 g, 610.5 mmol) was added to the mixture via a pressure equalizing addition funnel. The reaction was stirred at 0° C. for 1 hr and then warmed to rt and stirred for 2 hr. Then, the reaction was quenched with water (200 mL) and washed with 0.5 M HCl (×2), water (×1), and brine (×1). The organize layer was dried over MgSO4 and concentrated in vacuo. The crude product was azeotropically dried with benzene (250 mL), and then dissolved in 200 mL of benzene and 200 mL of tert-butanol was added. The resultant reaction was heated at reflux for 4 hr. After this period, the volatiles were removed in vacuo and the product then distilled on the high vacuum pump (bp 62-63° C., 0.1 mm Hg). The desired β-keto ester 1E was obtained (58.6 g, 315.5 mmol) in 57% yield as a clear, colorless, light oil.

1. additionaddition funnel
2. temperaturewarmed to rt
3. stirringstirred for 2 hr
4. customThen, the reaction was quenched with water (200 mL)
5. washwashed with 0.5 M HCl (×2), water (×1), and brine (×1)
6. dry with materialThe organize layer was dried over MgSO4
7. concentrationconcentrated in vacuo
8. dry with materialThe crude product was azeotropically dried with benzene (250 mL)
9. dissolutiondissolved in 200 mL of benzene
10. addition200 mL of tert-butanol was added
11. customThe resultant reaction
12. temperaturewas heated
13. temperatureat reflux for 4 hr
14. waitAfter this period
15. customthe volatiles were removed in vacuo
16. distillationthe product then distilled on the high vacuum pump (bp 62-63° C., 0.1 mm Hg)