Design and synthesis of new tricyclic quinoline derivatives from intramolecular cyclization of benzylidene malonic derivatives

Abstract

Quinolines are very important compounds due to their numerous biological and pharmacological applications. This article describes the synthesis of new tricyclic quinoline derivatives via intramolecular cyclization of malonic benzylidene derivatives. The malonic benzylidene derivatives 2a-c have been obtained by condensation of N-substituted aldehydes 1a-c with malononitrile or ethyl cyanoacetate. These latter have been cyclized by reflux in DMF to give the compounds 3a-f. The structures of the compounds have been determined by ¹H and ¹³C NMR spectroscopy, and High-Resolution Mass Spectrometry (HRMS) analysis. Two of the synthesized compounds have been identified and confirmed by X-ray crystallography.