[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9]([C:11]2[CH:16]=[CH:15][C:14]([F:17])=[C:13]([F:18])[C:12]=2[OH:19])=[O:10])=[CH:4][CH:3]=1.C(N(CC)CC)C.[C:27](Cl)(=[O:31])[CH:28]([CH3:30])[CH3:29]>C(Cl)Cl>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([CH2:8][C:9]([C:11]2[C:12]([O:19][C:27](=[O:31])[CH:28]([CH3:30])[CH3:29])=[C:13]([F:18])[C:14]([F:17])=[CH:15][CH:16]=2)=[O:10])=[CH:6][CH:7]=1A solution of 2-(4-chlorophenyl)-1-(3,4-difluoro-2-hydroxy-phenyl)-ethanone (4.5 g, 87% pure, 13.85 mmol) and triethylamine (1.7 g, 2.35 ml, 16.8 mmol, 1.2 eq.) in methylene chloride (100 ml) is treated dropwise at ambient temperature with isobutyryl chloride (1.79 g, 1.76 ml, 16.8 mmol, 1.2 eq.). After stirring for 5 h, the solution is washed successively with 2M HCl solution and saturated sodium hydrogen carbonate solution. The organic phase is dried over anhydrous magnesium sulphate, filtered and evaporated to dryness in vacuo to afford a black residue. This is triturated with methanol at room temperature overnight to afford a brown solid, which is filtered and washed with methanol. The solid is purified twice by flash chromatography (ethyl acetate/cyclohexane=1:9) to furnish the title compound.
Wird geladen…
