The condensation of 3,4-dimethoxyphenyacetic acid (I) with 2-aminoacetaldehyde diethylacetal (II) by means of 1,1'-carbonyldiimidazole (CDI) in CHCl3 gives N-(2,2-diethoxyethyl)-3,4-dimelhoxyphenylacetamide (III), which is cyclized by means of 48% aqueous HBr yielding 1,3-dihydro-7,8-dimethoxy-2H-3-benzazepin-2-one (IV). The reaction of (IV) with triethyloxonium tetrafluoroborate (V) in methylene chloride affords 2-ethoxy-7,8-dimethoxy-1H-3-benzazepine (VI), which is finally treated with ammonium chloride in refluxing methanol.