Synthesis of Methyl 7,9-Dimethyl-5-oxo-2,3,4,5-tetrahydro-1 H -benzo[ b ]azepine-1-carboxylate and Its Analogues

Article abstract of DOI:10.1055/s-0034-1378279

A high-yielding five-step synthesis of the title compound, methyl 7,9-dimethyl-5-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-1-carboxylate, starting from 2,4-dimethylaniline was developed. This synthesis involved N-alkylation of 2,4-dimethylaniline with ethyl 4-bromobutyrate to obtain ethyl 4-[(2,4-dimethylphenyl)amino]butanoate. Carbamoylation of the latter followed by hydrolysis of the resulting ester provided 4-[(2,4-dimethylphenyl) (methoxycarbonyl)amino]butanoic acid. Activation of the carboxylic acid using thionyl chloride followed by intramolecular cyclization via a Friedel-Crafts reaction using aluminum trichloride provided the title compound in good yield. Analogues of the title compound were also prepared similarly. Georg Thieme Verlag Stuttgart New York.