Ethylene Glycol → methyl 7-bromo-1-[(2-methyl-1,3-dioxolan-2-yl)methyl]-2,3-dihydro-1H-1-benzazepine-4-carboxylate

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A solution of methyl 7-bromo-1-(2-oxopropyl)-2,3-dihydro-1H-1-benzazepine-4-carboxylate (1.29 g), ethylene glycol (2.3 g) and p-toluenesulfonic acid monohydrate (36 mg) in toluene (10 ml) was heated to reflux for 3 days while removing water. After cooled to room temperature, an aqueous solution of sodium hydrogen carbonate was added to alkaline, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried with magnesium sulfate. After concentration under reduced pressure, the residue was separated and purified with column chromatography (ethyl acetate:hexane=1:4) to give methyl 7-bromo-1-[(2-methyl-1,3-dioxolan-2-yl)methyl]-2,3-dihydro-1H-1-benzazepine-4-carboxylate (992 mg).

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