[NH:1]([CH:8]1[CH2:13][CH2:12][N:11]([CH3:14])[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Cl:15][C:16]1[CH:23]=[CH:22][CH:21]=[CH:20][C:17]=1[C:18]#N.Cl.[OH2:25]>C1(C)C=CC=CC=1.B(Cl)(Cl)Cl>[Cl:15][C:16]1[CH:23]=[CH:22][CH:21]=[CH:20][C:17]=1[C:18]([C:7]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[NH:1][CH:8]1[CH2:13][CH2:12][N:11]([CH3:14])[CH2:10][CH2:9]1)=[O:25]To a 2.03M solution of boron trichloride (25×1.2 mmol) in toluene (14.8 ml) is dropwise added a solution of 4-anilino-1-methylpiperidine (4.79 g, 25 mmol) in toluene (40 ml) under ice cooling and stirring, and the resultant mixture is refluxed under stirring over a period of 1 hour. The toluene is evaporated under atmospheric pressure from the reaction mixture, and the residue is mixed with 2-chlorobenzonitrile (6.88 g, 25×2 mmol) and heated at 150° C. (bath temp.) over a period of 15 hours under stirring. After cooling, the reaction mixture is mixed with 2N hydrochloric acid (15 ml) and water (30 ml) and heated at 100° C. under stirring over a period of 20 minutes. After cooling, the reaction mixture is washed with ether, and the aqueous layer is neutralized with conc. aqueous ammoniac solution and shaken with methylene chloride. The methylene chloride layer is dried over anhydrous potassium carbonate and concentrated in vacuo. The residue is chromatographed on a column of alumina, which is eluted with methylene chloride. The eluate is concentrated, and the residue is crystallized from ether-petroleum ether to give 4-[2-(2-chlorobenzoyl)anilino]-1-methylpiperidine (8.15 g) as crystals melting at 128° to 129° C. The yield is 99%.
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