Fe2O3@[proline]–CuMgAl–LDH: A magnetic bifunctional copper and organocatalyst system for one‐pot synthesis of quinolines and 2H‐indazoles in green media

Abstract

A novel magnetic core–shell Fe2O3@[proline]–CuMgAl–L(ayered)D(ouble)H(ydroxide) was designed as an efficient bifunctional catalytic system. To this end, Cu (II) was combined with Mg and Al in the LDH structure and l‐proline was intercalated between LDH layers in order to perform a straightforward synthesis of quinolines and 2H‐indazoles as two important pharmaceutical N‐aryl‐substituted heterocyclic compounds. In this regard, a facile method was employed through consecutive condensation under a mild conditions in choline azide media, which played the role of a reagent and a solvent to avoid toxic solvents and hazardous azidation reagents. These techniques provided considerable improvement in terms of using green media, reducing starting materials, reaching higher yields and offering a shorter reaction time and lower temperature. In conclusion, it was found that the catalyst could be reused five times with no significant loss of activity.