Reaktion #42720

Reaktionsgleichung

sulfuric acid

2-Bromothiophene

magnesium

dimethyl oxalate

→

title compound

Ausbeute 60.0%

Hydroxydithien-2-ylacetic Acid Methyl Ester

Ausbeute 60.0%

Lösungsmittel

diethyl ether

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was heated
2. 2
   Temperaturat reflux (45° C.) for 45 min
3. 3
   Temperaturto cool to ambient temperature
4. 4
   workup.STIRRINGThe reaction mixture was stirred at ambient temperature for 1 h
5. 5
   Sonstigethe organic layer was separated
6. 6
   Waschenwashed with dilute aqueous sodium bicarbonate solution (100 mL), water (100 mL)
7. 7
   Trocknendried with sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated under reduced pressure
10. 10
    SonstigeThe resulting solid residue was recrystallized from tetrachloromethane (˜1 g/3 mL)

Vorschrift

2-Bromothiophene (9.68 mL, 0.1 mol) was slowly added to a stirred mixture of magnesium turnings (2.7 g, 0.11 mol) in diethyl ether (100 mL) under a nitrogen atmosphere at 0° C. The reaction mixture was stirred at 35° C. for 3 h and then dimethyl oxalate (5.9 g, 0.05 mol) in diethyl ether (150 mL) was added dropwise. The reaction mixture was heated at reflux (45° C.) for 45 min and then the mixture was allowed to cool to ambient temperature and 1.25 M sulfuric acid (150 mL) was added. The reaction mixture was stirred at ambient temperature for 1 h and then the organic layer was separated and washed with dilute aqueous sodium bicarbonate solution (100 mL), water (100 mL), dried with sodium sulfate, filtered and concentrated under reduced pressure. The resulting solid residue was recrystallized from tetrachloromethane (˜1 g/3 mL) to yield the title compound (7.68 g, 30 mmol, 60%).

Quelle