Synthesis of Novel Substituted Dibenzonaphthyridines

Heterocyclic compounds are very widely distributed in nature and are essential to life as they play a vital role in the metabolism of living cells. There are a vast number of pharmacologically active heterocyclic compounds of which many are in regular therapeutic usage. Among various heterocyclic compounds, quinoline-based drugs such as quinine, chloroquine, pamaquine and quinacrine are well known for their antimalarial property. In this regard some of the anilinoquinolines particularly attracted considerable attention [1]. The interest in naphthyridine derivatives is due to the exceptionally broad spectrum of their biological activities. They are used for the diagnosis and therapy of diseases of humans including AIDS [2, 3] and cancer [4]. Some of the dibenzonaphthyridines, i. e. quinoline dimers, have been shown to possess various biological activities like antimicrobial [5] and anticancer [6] activity, and are potent and selective 3phosphoinostide-dependent kinase-I inhibitors [7]. A detailed survey of the literature points out that many reactions of chloroquinolines aimed to get substitution products possessing biological activity [8, 9]. Since the discovery of the first naphthyridine by Reissert in the year 1893 [10], many procedures have been evolved for the synthesis of simple benzoand dibenzonaphthyridines [11 – 14], but only very few accomplished the construction through anilinoquinolines, i. e. (N-phenylamino)quinolines [15, 16]. Herein we opt to synthesize the various 3-substituted dibenzonaphthyridines holding a diversity of substituents such as aliphatic, aromatic and heterocyclic