5-Ethyl-4-phenyl-thiophene-2-carboxylic acid → 1-(5-Ethyl-4-phenyl-thiophen-2-yl)-ethanone
Reaktionsgleichung
[CH2:1]([C:3]1[S:7][C:6]([C:8]([OH:10])=O)=[CH:5][C:4]=1[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)[CH3:2].[Li][CH3:18]>C1COCC1>[CH2:1]([C:3]1[S:7][C:6]([C:8](=[O:10])[CH3:18])=[CH:5][C:4]=1[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)[CH3:2]Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
At 5° C. a solution of 5-ethyl-4-phenyl-thiophene-2-carboxylic acid (180 mg, 0.775 mmol) in THF (4 mL) is treated with MeLi (0.9 mL, 1.6 M in diethyl ether). The reaction mixture is stirred at rt for 30 min before another portion of MeLi (0.5 mL) is added. Stirring is continued for 1 h, the reaction is quenched by adding water (50 mL) and extracted with EA. The organic extract is dried over MgSO4, the solvent is removed in vacuo, and the crude product is purified by CC on silica gel eluting with heptane:EA 30:1 to give 1-(5-ethyl-4-phenyl-thiophen-2-yl)-ethanone (64 mg) as a colourless oil; LC-MS: tR=1.03 min, [M+1+MeCN]+=272.15; 1H NMR (CDCl3): δ 7.60 (s, 1H), 7.47-7.32 (m, 5H), 2.91 (q, J=7.6 Hz, 2H), 2.54 (s, 3H), 1.30 (t, J=7.6 Hz, 3H).