Reaktion #716340

Reaktionsgleichung

hydrochloric acid

dimethylformamide

2-methoxythiophene

n-butyllithium

→

5-methoxy-2-thiophenecarbaldehyde

Ausbeute 72.4%

Lösungsmittel

tetrahydrofuran hexamethylphosphoramide

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm to room temperature
2. 2
   workup.STIRRINGwhile stirring
3. 3
   ExtraktionOrganics were extracted with ether (2×25 mL)
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated
7. 7
   WaschenThe crude residue was subjected to chromatography on silica gel with gradient elution (10-12% ethyl acetate in hexanes)

Vorschrift

To a solution of 2-methoxythiophene (79 mg, 0.69 mmol) in 3.5 mL of 9:1 tetrahydrofuran/hexamethylphosphoramide under argon at −78° C. was added n-butyllithium (0.30 mL, 2.5 M in hexanes) dropwise. After stirring at −78° C. for 20 minutes, dimethylformamide (0.27 mL, 3.5 mmol) was added in a single portion and the reaction mixture allowed to warm to room temperature while stirring, before being poured into 25 mL of 1 N hydrochloric acid. Organics were extracted with ether (2×25 mL), dried over magnesium sulfate, filtered and concentrated. The crude residue was subjected to chromatography on silica gel with gradient elution (10-12% ethyl acetate in hexanes) to give 5-methoxy-2-thiophenecarbaldehyde (71 mg, 72%). Used without further characterization.

Quelle