The condensation of 4,5-dimethoxyphthalic anhydride (I) with 3-[[2-(3,4-dimethoxyphenyl)ethyl]methylamino]propylamine (II) in refluxing acetic acid gives 5,6-dimethoxy-2-[3-[[2-(3,4-dimethoxyphenyl)ethyl]methylamino]propylphthalamide (III), which is reduced with Zn in refluxing acetic acid.