Fe<sub>2</sub>O<sub>3</sub>@[proline]–CuMgAl–LDH: A magnetic bifunctional copper and organocatalyst system for one‐pot synthesis of quinolines and 2<i>H</i>‐indazoles in green media
Naghmeh Esfandiary, Akbar Heydari
Abstract
A novel magnetic core–shell Fe 2 O 3 @[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.