Thionyl Chloride → 3-methoxycarbonyl-7-[3-(1-benzoylpiperidin-4-yl)-1-oxopropyl]-2,3,4,5-tetrahydro-1H-3-benzazepine

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Reaction Conditions

Reaction Steps

Under ice-cooling, 1.5 ml of thionyl chloride was added dropwise to 1.08 g (4.1 mmol.) of 3-(1-benzoylpiperidin-4-yl)propionic acid obtained in Reference Example 9. The mixture was stirred for 40 minutes at 0° C., then thionyl chloride was distilled off. The residue was dissolved in 20 ml of 1,2-dichloroethane, to which was added 0.81 g (3.9 mmol.) of 3- methoxycarbonyl-2,3,4,5-tetrahydro-1H-3-benzazepine obtained in Reference Example 10. To the mixture was added 1.75 g (13.1 mmol.) of aluminum chloride in small portions. The mixture was stirred for one hour at room temperature, then the reaction mixture was poured into ice-water and extracted with dichloromethane. The organic layers were combined and washed with water once, then dried over anhydrous sodium sulfate, followed by distilling off the solvent. Purification by means of a silica gel column chromatography gave 1.46 g (83%) of 3-methoxycarbonyl-7-[3-(1- benzoylpiperidin-4-yl)-1-oxopropyl]-2,3,4,5-tetrahydro-1H-3-benzazepine. Recrystallization from ethyl acetate --n-hexane gave colorless needles, m.p. 120°-123° C.

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