反应详情

0.1 mol of 2,3-difluoro-4-ethoxybenzoic acid (preparable from 2,3-difluorophenol by alkylation using diethyl sulfate/potassium carbonate in dimethylformamide, metallation of the 2,3-difluorophenetole in the 4-position using butyllithium/tetramethylethylenediamine in tetrahydrofuran (THF) at -70° to -80° and reaction with solid carbon dioxide), 0.01 mol of 4-dimethylaminopyridine and 0.1 mol of trans-4-propylcyclohexanol are initially introduced in 150 ml of dichloromethane, a solution of 0.1 mol of dicyclohexylcarbodiimide in 30 ml of dichloromethane is added dropwise at 10° with stirring, and the mixture is subsequently stirred at room temperature for 15 hours. The mixture is filtered through silica gel with suction, the solvent is evaporated, and trans-4-propylcyclohexyl 2,3-difluoro-4-ethoxybenzoate is obtained as a residue and is purified by crystallization. Mp. 93°, cp. (48°).

1. customat -70° to -80°
2. stirringthe mixture is subsequently stirred at room temperature for 15 hours
3. filtrationThe mixture is filtered through silica gel with suction
4. customthe solvent is evaporated