4-Phenyl-5-(trifluoromethyl)thiophene-2-carboxylic acid → 1-[4-Phenyl-5-(trifluoromethyl)-2-thienyl]ethan-1-one
Reaction equation
[C:1]1([C:7]2[CH:8]=[C:9]([C:16]([OH:18])=O)[S:10][C:11]=2[C:12]([F:15])([F:14])[F:13])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Li][CH3:20]>C1COCC1>[C:1]1([C:7]2[CH:8]=[C:9]([C:16](=[O:18])[CH3:20])[S:10][C:11]=2[C:12]([F:13])([F:14])[F:15])[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 4-phenyl-5-trifluoromethyl-thiophene-2-carboxylic acid (272 mg, 1.0 mmol) in THF (10 mL), a solution of MeLi (1.30 mL, 1.6 M solution in diethyl ether) is added. The dark red reaction mixture is stirred at it for 10 min. The reaction is quenched by adding sat. aq. NH4Cl (10 mL). The organic phase is separated, dried over Na2SO4 and evaporated. The crude product is purified by prep. HPLC (Waters Xterra MS18, 75×30 mm, 10 μm, 10 to 95% acetonitrile in water containing 0.5% formic acid) to give 1-(4-phenyl-5-trifluoromethyl-thiophen-2-yl)-ethanone (31 mg) as pale yellow oil, LC-MS: tR=1.06 min, 1H NMR (CDCl3): δ 7.62-7.60 (m, 1H), 7.45-7.40 (m, 5H), 2.60 (s, 3H).