A mixture of 1-benzyl-4-(4-phenyl)-4-(acetaminomethyl)piperidine, 3-(4-
fluorobenzoyl)propyl bromide, sodium bicarbonate and anhydrous acetone was
stirred and heated under reflux. The resulting mixture was filtered while still
hot, and the filtrate was concentrated to dryness under reduced pressure. The
residue was washed with ether to give 1-benzyl-1-[3-(4-fiuorobenzoyl)propyl]-
(4-phenyl-4-acetaminomethyl)piperidinium bromide.
To a stirred mixture of thiophenol and 15% (W/W) aqueous sodium hydroxide
was added the 1-benzyl-1-[3-(4-fluorobenzoyl)propyl]-(4-phenyl-4-
acetaminomethyl)piperidinium bromide and the mixture was heated to 85°-
90°C for 2 h. After cooling, solid matter precipitated was collected by filtration
and washed with water to give 1-[3-(4-fluorobenzoyl)propyl]-4-
(acetaminomethyl)-4-phenylpiperidine, melting point 111°-112°C.
