Reaktion #1262374

Reaktionsgleichung

epibromohydrin

epibromohydrin

potassium carbonate

diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate

propylene

→

diethyl 2,3-dihydro-2-(hydroxymethyl)thieno[3,4-b][1,4]dioxine-5,7-dicarboxylate

Ausbeute 55.0%

Lösungsmittel

hexane

water

ethyl acetate

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter heating
2. 2
   Temperaturto reflux for 1 hour
3. 3
   Temperaturthe reaction heated
4. 4
   Temperaturto reflux overnight
5. 5
   Einengenwas concentrated by evaporation
6. 6
   workup.ADDITIONpoured into 500 ml water
7. 7
   Extraktionextracted with methylene chloride until the
8. 8
   Waschenorganic wash no longer indicated product
9. 9
   WaschenThe organic fractions were washed with saturated brine
10. 10
    Trocknenthen dried with magnesium sulfate
11. 11
    SonstigeThe solvent was removed under reduced pressure
12. 12
    Sonstigeto give a yellow solid
13. 13
    Sonstigeto give

Vorschrift

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.

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