Dimethyl Sulfoxide → trans-7-Chloro-5-(2-chlorophenyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetaldehyde

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Reaction Steps

To 25 ml of dichloromethane solution containing 0.70 ml of oxalyl chloride was added 5 ml of dichloromethane solution containing 0.71 ml of dimethylsulfoxide at -78° C., followed by stirring for 5 minutes. To the solution was slowly added 10 ml of dichloromethane solution containing 1.69 g of trans-7-chloro-5-(2-chlorophenyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-ethanol obtained in Example 160, followed by stirring for 15 minutes at -78° C. To the reaction mixture was added 2.79 ml of triethylamine and the mixture was further stirred for one hour at 0° C. and for 1.5 hours at room temperature. After the addition of 100 ml of water, extraction was performed with 100 ml of dichloromethane. The dichloromethane layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated off under reduced pressure. The residue was purified by column chromatography using silica gel (eluent, hexane:ethyl acetate=1:1) to give 1.08 g of trans-7-chloro-5-(2-chlorophenyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetaldehyde as light-yellow crystals, m.p. 173° to 176° C.

Provenance & Evidence