Reduction of N-Nitrosaminoquinolinediones with LiAlH4 - An Easy Path to New Tricyclic Benzoxadiazocines

Abstract

3-Butylaminoquinolinediones (1) react with NaNO2 in AcOH to give the corresponding N-nitrosoderivatives (2). The analogous reactions of 4-hydroxy-3-butylaminoquinolinediones (5), prepared by the reduction of 1 with NaBH4, produce the corresponding nitrosamines (4). The reduction of both 2 and 4 with Zn under different conditions was non-productive, but the reduction of both compounds with LiAlH4 at the oxo and lactame groups yielded impure products, generating new tricyclic benzoxadiazocines (9) by a reaction with HNCO. All compounds were characterized by IR, 1H-, and 13C-NMR (in some cases, 15N-NMR also) spectroscopy and EI and/or ESI mass spectrometry. The X-ray structure of compound 9g was determined. © 2016 Verlag Helvetica Chimica Acta AG, Zürich.