Reacción #1760341

Ecuación de reacción

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

Rendimiento 55.0%

Disolventes

hexane

water

ethyl acetate

ethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter heating
2. 2
   Temperaturato reflux for 1 hour
3. 3
   Temperaturathe reaction heated
4. 4
   Temperaturato reflux overnight
5. 5
   Concentraciónwas concentrated by evaporation
6. 6
   workup.ADDITIONpoured into 500 ml water
7. 7
   Extracciónextracted with methylene chloride until the
8. 8
   Lavadoorganic wash no longer indicated product
9. 9
   LavadoThe organic fractions were washed with saturated brine
10. 10
    Secadothen dried with magnesium sulfate
11. 11
    OtroThe solvent was removed under reduced pressure
12. 12
    Otroto give a yellow solid
13. 13
    Otroto give

Procedimiento

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 chromoatography 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.

Fuente