Thionyl Chloride → 3-(1-Acetyl-4-piperidinyl)propionyl chloride

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Reaction Steps

3-(1-Acetyl-4-piperidinyl)propionic acid (6.82 g, 34.2 mmol) was added portionwise to thionyl chloride (35 ml) with ice-bath cooling. After the mixture was stirred for 5 minutes, the excess thionyl chloride was distilled off and the residue was washed with hexane to provide 3-(1-acetyl-4-piperidinyl)propionyl chloride as light-yellow solid. Aluminum chloride (13.3 g, 99.7 mmol) powders were added in small portions to admixed solution of the above acid chloride and 2-formyl-2,3,4,5-tetrahydro-1H-2-benzazepine (5.00 g, 28.5 mmol), obtained in Reference Example 5, in 1,2-dichloroethane (25 ml) with ice-bath cooling. This mixture was stirred at room temperature for 18 hours. It was then poured in ice-water and extracted with ethyl acetate. The extract was washed with saturated NaCl/H2O and dried over MgSO4 and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (eluent: ethyl acetate-methanol=9:1) to provide 3-(1-acetyl-4-piperidinyl)-1-(2-formyl-2,3,4,5-tetrahydro-1H-2-benzazepin-8-yl)-1-propanone (7.06 g) as light-yellow oil.

Provenance & Evidence