An efficient and green one-pot synthesis of indazolo[1,2-b]-phthalazinetriones via three-component reaction of aldehydes, dimedone and phthalhydrazide in the presence of Fe3O4@SiO2 nanoparticles

Nitrogen heterocyclics have been the subject of intense research because of theiroutstanding biological properties and wide range of applications to pharmaceuticalcompounds, agrochemicals and synthetic intermediates. Among a large variety ofheterocyclic compounds, heterocycles containing phthalazine moiety are of interest becausethey show several pharmacological and biological activities [1].Multicomponent reactions (MCRs) are defined as one-pot processes in which three or moresubstrates combine either simultaneously (so-called tandem or domino reactions), orthrough a sequential addition procedure that does not require any change of solvent. MCRsare gaining more and more importance especially in the total synthesis of natural productsand medicinal heterocyclic compounds because of their simplicity, high yield of theproducts and short reaction times [2].Nanoscience and nanotechnology is an amazing growing research area in recent years thatinclude the preparation, characterization and application of nanostructures with variousshapes and sizes in many chemical transformations.Core-shell nanoparticles have recently been subject to extensive research for the combinedfunctionalities of cores and shells which endow them with great application potentials invarious fields [3].With the aim to develop more efficient synthetic processes, reduce the number of separatereaction steps, and minimize by-products we report here a green and mild method for thepreparation of indazolo[1,2-b]-phthalazinetriones in high yields and short reaction timesusing Fe3O4@SiO2 core-shell nanoparticles as an effective and green catalyst.