In methanol (250 ml) and THF (250 ml) was dissolved methyl 1-formyl-7-(4-morpholinophenyl)-2,3-dihydro-1H-1-benzazepine-4-carboxylate (3.54 g). To the solution was added 1N sodium hydroxide solution (90 ml), and the mixture was stirred at room temperature overnight and concentrated. To the mixture was added water, and the mixture was neutralized with 1N hydrochloric acid and extracted with ethyl acetate. The organic layer was dried with anhydrous magnesium sulfate, and the solvent was evaporated to give 1-formyl-7-(4-morpholinophenyl)-2,3-dihydro-1H-1-benzazepine-4-carboxylic acid (3.30 g) as colorless crystals.
