Reaktionsgleichung
[Br:1][C:2]1[S:6][CH:5]=[C:4]([C:7]([OH:9])=[O:8])[CH:3]=1.Cl.O.[CH3:12]O>>[CH3:12][O:8][C:7]([C:4]1[CH:3]=[C:2]([Br:1])[S:6][CH:5]=1)=[O:9]Komponenten
5
Versuchsvorschrift
Prepare a solution of 5-bromothiophene-3-carboxylic acid (500 mg, 2.41 mmol) in methanol (5 mL). Add concentrated hydrochloric acid (0.1 mL). Reflux the mixture for 3 hours, cool to room temperature, pour into water, and extract with diethyl ether (3×10 mL). Wash the combined organic phases with water (10 mL), then saturated aqueous sodium hydrogencarbonate (10 mL). Dry (magnesium sulfate), filter and concentrate. Perform flash chromatography on silica gel eluting with 5:1 hexane/ethyl acetate to afford 409 mg of 5-bromothiophene-3-carboxylic acid methyl ester as a white solid. 1H NMR (CDCl3) δ 8.10 (d, J=1.5 Hz, 1H), 7.17 (d, J=1.5 Hz, 1H), 3.86 (s, 3H).
Aufarbeitung
- temperatureReflux the mixture for 3 hours
- extractionextract with diethyl ether (3×10 mL)
- washWash the combined organic phases with water (10 mL)
- dry with materialDry (magnesium sulfate)
- filtrationfilter
- concentrationconcentrate
Quellen und Nachweise
- ORD-Eintrag
- ord-b62b682013a841f3ac007d70d297e451
- Quelldatensatz
- uspto-grants-2007_09
- Patentnummer
- US07265246B2
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