An efficient and rapid synthesis of functionalized quinoline derivatives

For more than a century, heterocycles have constituted one the largest areas of research in organic chemistry. Amongst the heterocycles, N-based heterocycles represent a highly important class of compounds which are widely used in materials science, agrochemistry, and medicinal chemistry [1]. Quinoline is one of the most popular N-heterocyclic compounds incorporated into the structures of many pharmaceuticals [2]. Enaminones and related compounds are versatile synthetic intermediates in organicchemistry. They are widely used for the synthesis of a variety of heterocycles especially N-heterocyclic compounds in the past several years [3]. herein we report an efficient synthesis of functionalized quinoline derivatives 5 through a multicomponent reaction of enaminone derived from the addition of various anilines 1 to dimedone 2 with aromatic aldehydes 3 and cyanoacetohydrazide 4, respectively in melt conditions and then in ethanol/water as a green medium (Fig 1). The significant features of this method are green methodology, easy work-up, readily available starting materials, high atom economy, compatibility with various functional groups and good product yields. All structures were confirmed by Mass, IR, 1H- and 13CNMR analyses.