چكيده به لاتين
The Huisgen cycloaddition reaction catalysed by copper (I), discovered is to date the most effective and most used "click" reaction. Since its discovery, the 1,3-dipolar cycloaddition between an alkyne and a copper-catalyzed azide (CuAAC) has become one of the major reactions of the chemist's arsenal. The presence of copper makes it possible to accelerate the reaction considerably but also to obtain selectively 1,4-triazole, one of the two possible isomers. The objective of this work was to develop a high performance copper catalysts for this transformation.
Shilajit, a natural substance found mainly in the Himalayas and formed for centuries by the gradual decomposition of certain plants by the action of microorganisms was used as ligand.
The novel magnetic Fe2O3 supported natural phytocomplex shilajit-copper (Fe2O3/Sh/Cu)¬ catalyst was prepared and characterized using FTIR, XRD, EDX, TEM, SEM, and VSM. This magnetic catalyst exhibited excellent catalytic activity for the synthesis of a wide variety of 1,4-disubstituted-1,2,3- triazoles via a one-pot three-component click reactions of terminal alkynes, sodium azide, and alkyl bromides/chlorides at 40-60 oC in H2O:EtOH (1:1) under reducing agent-free conditions. The main advantages of this procedure are the reducing agent-free conditions, high yields, easy separation of the catalyst using an external magnet and efficient recycling.
