An efficient one-pot multi-component synthesis of spirooxindoles using Fe3O4/g-C3N4 nanocomposite as a green and reusable catalyst in aqueous media

Article abstract of DOI:10.1016/j.molstruc.2020.129654

In this study, an efficacious method is described for the synthesis of spirooxindole derivatives using Fe₃O₄/g-C₃N₄ as a green catalyst. This is a one-pot three-component condensation in water as a clean and environmentally favorable media. The present procedure proposes various remarkable privileges such as mild reaction conditions, simple work-up procedure and environment friendly. Moreover, the catalyst used is easily recovered by the external magnetic field and reused without significant deterioration in catalytic activity after at least six times.

Full text of DOI:10.1016/j.molstruc.2020.129654

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An efficient one-pot multi-component synthesis of spirooxindoles
using Fe3O4/g-C3N4 nanocomposite as a green and reusable
catalyst in aqueous media
Fatemeh Kamali , Farhad Shirini
PII:
S0022-2860(20)31967-0
DOI:
Reference:
https://doi.org/10.1016/j.molstruc.2020.129654
MOLSTR 129654
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Journal of Molecular Structure
Received date:
Revised date:
Accepted date:
2 June 2020
5 November 2020
21 November 2020
Please cite this article as: Fatemeh Kamali , Farhad Shirini , An efficient one-pot multi-
component synthesis of spirooxindoles using Fe3O4/g-C3N4 nanocomposite as green
a
and reusable catalyst in aqueous media, Journal of Molecular Structure (2020), doi:
https://doi.org/10.1016/j.molstruc.2020.129654
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An efficient one-pot multi-component synthesis of spirooxindoles
using Fe3O4/g-C3N4 nanocomposite as a green and reusable
catalyst in aqueous media
Fatemeh Kamali and Farhad Shirini*
Department of Chemistry, College of Science, University of Guilan, Rasht, 41335-19141, Iran
E-mail address: shirini@guilan.ac.ir, Tel/Fax: +98 131 3233262
Highlights:
 Introduction of Fe3O4/g-C3N4 nanocomposite as an efficient magnetic nanocatalyst.
 Application of Fe3O4/g-C3N4 in the promotion of the synthesis of spirooxindoles.
 Simple and easy experimental procedure.
 Availability and reusability of the catalyst.
 Use of water as an eco-friendly solvent.
Abstract
In this study, an efficacious method is described for the synthesis of spirooxindole derivatives
using Fe3O4/g-C3N4 as a green catalyst. This is a one-pot three-component condensation in
water as a clean and environmentally favorable media. The present procedure proposes
various remarkable privileges such as mild reaction conditions, simple work-up procedure
and environment friendly. Moreover, the catalyst used is easily recovered by the external
magnetic field and reused without significant deterioration in catalytic activity after at least
six times.

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Keywords: Spirooxindoles, magnetic nanocomposite, water, reusable, catalyst, Fe3O4/g-
C3N4.
1. Introduction
Green chemistry as a powerful tool plays momentous role in various research fields such as
synthetic organic, biomedical, industrial chemistry, etc. [1-2]. An important step in the
successful development of green chemistry is the design of highely efficienty and
inexpensive synthetic methods, and therefore requires short and efficacious synthetic
sequences for this purpose.
MCRs employ a minimum of three reactants or reaction centers, and most of the contents
from the starting materials are combined to provide collection of complex scaffolds from the
easily available precursors in a simple one-pot procedure [3-6]. Based on this, these types of
reactions comply with the principles of green chemistry by saving time and energy, while
containing the high atom-economy, quick and simple implementation. Therefore, there is
increasing interest in multicomponent reactions to rapidly build versatile scaffolds [7-8].
Newly execution of MCRs in water as reaction medium has engrossed extremely attention,
because water is an inexpensive, safe, and environmentally mild solvent. Sometimes it
exhibits higher reactivity and selectivity compared to other conventional organic solvents
owing to its strong hydrogen bonding ability [9-10].
In the last years, the spiro [4H-pyran] derivatives have attracted notable attention in organic
synthesis. The spirooxindole system is the core structure of diversity of natural alkaloieds.
Moreover, they have momentous medicinal properties including anticancer [11], antioxidant
[12], antimicrobial [13], antifungal [14], anti HIV [15] and antitubercular activities [16]. Due
to the aforesaid properties a variety of methods using diverse types of catalysts have been
reported in the literature for the procurement of these types of compounds [17-20].
On the other hand, we have observed a drastic growth of interest in materials with graphite-
like structures, such as graphene (G) and graphene oxide (GO), because of their unparalleled

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attributes including large surface area and hexagonal array of carbon atoms in graphite sheets
which are ideal for strong interactions with other molecules [21-30].
As a new two dimensional graphite analogue, graphitic carbon nitride (g-C3N4) have
absorbed much regard in research fields [31-33]. Friendly polymeric nature of g-C3N4 assures
enough flexibility of the structure, which can serve as a host matrix of distinguished
compatibility to different inorganic nanoparticles [34-36]. Further, procurement of g-C3N4
can be simply performed by thermal condensation of low-cost nitrogen rich precursors, and
therefore, it is economic and environmentally [37]. However, a significant impediment which
has limited the further expansion of g‐C3N4 in the field of catalysis is difficulty of its
separation from reaction mixture due to its very dispersive nature.
Recently, magnetic nano particles (MNPs) have imbibed striking attention in the area of
chemical research due to their inimitable applications such as their utilization for drug
delivery systems [38], cell separation [39], magnetic resonance imaging [40], cancer
treatments through hyperthermia [41] and protein separation [42].
According to the above, preparation of magnetically separable nanocomposites based on g‐
C3N4 would enable their simple separation from the solution with an external magnet.
Magnetic substance, Fe3O4 will not only raise the recycling rate, but also the catalytic activity
of the intelligent material. The Fe3O4/g-C3N4 nanocomposite is g-C3N4 sheets decorated by
Fe3O4 nanoparticles.
As a part of our program in the development of expedient methods and regarding to unique
physicochemical characteristics of graphitic carbon nitride (g-C3N4) such as its excellent
thermal and chemical stability, low cost, non-toxicity, and “earth-abundant” nature, herein,
we have introduced a facile and benign protocol for the synthesis of spirooxindoles using
Fe3O4/g-C3N4 nanocomposite as catalyst. For this purpose, at the first step pure g‐C3N4 was
fabricated via one-step polymerization of melamine as a cheap feedstock without any organic