2,2,2-Trichloroethyl chloroformate → cis-3-Phenyl-1-(2,2,2-trichloroethoxycarbonyl)-4-(4-trifluoromethylphenoxy)piperidine

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Reaction Steps

0.46 g of anhydrous potassium carbohate and 0.5 ml of 2,2,2-trichloroethyl chloroformate are added under nitrogen to a solution of 1.11 g of the free base of cis-1-methyl-3-phenyl-4-(4-trifluoromethylphenoxy)piperidine of Example 22 in 10 ml of dry benzene. After 1 hour at room temperature the mixture is refluxed 18 hours. Another 0.045 ml of 2,2,2-trichloroethyl chloroformate is added, the mixture is again refluxed 18 hours, then cooled and partitioned between ether and water. The organic phase is washed with saturated aqueous NaCl solution, dried over anhydrous Na2SO4, and concentrated in vacuo to an oil. This material is dissolved in benzene and filtered through a column of silica gel, then is further purified by preparative chromatography on five 2 mm silica preparative plates, using 3:1 petroleum ether as solvent. A nearly colorless glass of cis-3-phenyl-1-(2,2,2-trichloroethoxycarbonyl)-4-(4-trifluoromethylphenoxy)piperidine is obtained.

Provenance & Evidence