C([N:8]1[CH2:13][CH2:12][CH:11]([O:14][C:15]2[CH:20]=[CH:19][C:18]([C:21]([F:24])([F:23])[F:22])=[CH:17][CH:16]=2)[CH2:10][CH2:9]1)C1C=CC=CC=1.[H][H]>[Pd].C(O)C>[F:24][C:21]([F:22])([F:23])[C:18]1[CH:19]=[CH:20][C:15]([O:14][CH:11]2[CH2:10][CH2:9][NH:8][CH2:13][CH2:12]2)=[CH:16][CH:17]=1A solution of 46.0 g of 1-benzyl-4-(p-trifluoromethylphenoxy)piperidine, the free base of Part (a), in 250 ml. of 95% ethanol is treated with 6.0 g of 10% palladium-on-charcoal catalyst and is shaken with hydrogen gas at 50° C. until the theoretical amount of hydrogen is absorbed. The suspension is cooled, filtered, and the solvent is removed. The residual oil is fractionally distilled under reduced pressure and the fraction which boils at 74°-76° C/0.05 mm is collected. The collected oil crystallizes on standing to give a solid of 4-(p-trifluoromethylphenoxy)piperidine.
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