Esterification of 3,4-(methylenedioxy)phenylacetic acid (I) with methanol in the presence of sulfuric acid provided methyl ester (II). Fiedel Crafts acylation of (II) with 4-nitrobenzoic acid (III) under the action of P2O5 in refluxing dichloroethane yielded ketone (IV). This compound was refluxed with hydrazine hydrate in ethanol to afford benzodiazepinone (V). Finally, the nitro group was reduced by hydrogenation in acetic acid with Pd/C as the catalyst or with Raney-Ni and hydrazine to give the corresponding amine.