反应详情

7.7 mL (0.0902 mol) of epibromohydrin and 1.92 g (0.0139 mol) of potassium carbonate were dissolved in 100 mL water and added to a refluxing mixture of 16.11 g (0.0694 mol) diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate in 350 mL ethanol. After heating to reflux for 1 hour, an additional 5.3 mL (0.0624 mol) epibromohydrin was added and the reaction heated to reflux overnight. Upon cooling to room temperature the reaction was concentrated by evaporation and then poured into 500 ml water. The mixture was acidified and then extracted with methylene chloride until the organic wash no longer indicated product was present. The organic fractions were washed with saturated brine then dried with magnesium sulfate. The solvent was removed under reduced pressure to give a yellow solid. Column chromatography was performed using 60% ethyl acetate in hexane to give a 70:30 mixture of the product and propylene isomer in 55% yield as a white solid. Structure and purity were confirmed by 1H/13C NMR and LC-MS.

1. temperatureAfter heating
2. temperatureto reflux for 1 hour
3. temperaturethe reaction heated
4. temperatureto reflux overnight
5. concentrationwas concentrated by evaporation
6. additionpoured into 500 ml water
7. extractionextracted with methylene chloride until the
8. washorganic wash no longer indicated product
9. washThe organic fractions were washed with saturated brine
10. dry with materialthen dried with magnesium sulfate
11. customThe solvent was removed under reduced pressure
12. customto give a yellow solid
13. customto give