Next Article in Journal
A Comparative Theoretical and Spectroscopic Study of Aminomethylbenzoic Acid Derivatives as Potential NLO Candidates
Previous Article in Journal
Synthesis and Structure of Novel Potentially Bioactive Amphiphilic -O-(N)-Glycosides
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Magnetized Dextrin: Eco-Friendly Effective Nanocatalyst for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives †

Zeinab Amiri-Khamakani
Fereshte Hassanzadeh-Afruzi
Ali Maleki
Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran
Author to whom correspondence should be addressed.
Presented at the 24th International Electronic Conference on Synthetic Organic Chemistry, 15 November–15 December 2020; Available online:
Chem. Proc. 2021, 3(1), 101;
Published: 14 November 2020


Dextrin is a water soluble polysaccharide obtained by hydrolysis of starch and glycogen. This low molecular weight biopolymer with valuable properties such as biodegradability, biocompatibility, good availability, and high reactivity can be an appropriate substance to fabricate the environmentally friendly catalysts. The magnetized dextrin was prepared via facile co-precipitation procedure of iron salts in the presences of dextrin under alkaline condition. Then, it was characterized by different conventional analyses. Eventually, the catalytic application of obtained nanocomposite was evaluated for the synthesis dihydropyrano[2,3-c]pyrazole derivatives through multicomponent reaction of hydrazine hydrate, ethyl acetoacetate, aromatic aldehydes, and malononitrile. Biocompatible nanocatalyst, simple procedure, short reaction times, and catalyst reusability after four consecutive runs with negligible decrease in catalytic efficiency are some merits of the presented method.

Published: 14 November 2020

1. Introduction

One of the important achievements of the principles of green chemistry is the design and fabrication of biocompatible catalysts [1]. Dextrin is a low molecular weight polysaccharide with chemical formula (C6H10O5) n which is obtained from the hydrolysis of starch or glycogen. Dextrin is composed of D-glucose units linked by α-(1 → 4) or α-(1 → 6) glycosides bonds (Figure 1) [2]. As a natural polymer, dextrin has outstanding properties for instance have great number of hydroxyl groups, water solubility, biodegradability, good stability, low cost, and non-toxicity. Therefore, it has been used in environmental chemistry, biochemistry, pharmaceutical chemistry, and more recently in catalysts [3].
The presence of a large number of reactive functional groups in its chemical structure provided chemical modification to fabricate the diverse compounds and with catalytic potential application. In this work, a composite consisting of dextrin and Fe3O4 MNPs prepared via simple procedure. This composite has the advantages of dextrin for instance the presence of large number of hydroxyl groups that can form a hydrogen bond with the starting reactants and accelerate the reaction as well as the advantages of Fe3O4 MNPs such as high surface area, Lewis acid sites, and the possibility of recovery and reusability. Multicomponent reactions (MCRs) are one of the most important approach to construct the organic compounds which offer outstanding benefits such as high atomic efficiency, time and energy saving, and environmental friendliness [3,4]. Dihydropyrano [2,3-c]pyrazole is a heterocyclic compound with potential application in medicinal and pharmaceutical chemistry and significant role as building blocks in the preparation of valuable drugs for instance antimicrobial, antiviral, analgesic, anti-inflammatory, anticancer, and anti-proliferative [5]. In continues to our research on MCRs and nanomaterials [6,7,8], in present work, magnetized dextrin was used as a hybrid nanocatalyst in the synthesis of dihydropyrano[2,3-c]pyrazoles derivatives, via one-pot condensation of ethyl acetoacetate, hydrazine hydrate, malononitrile, and aromatic aldehydes (Scheme 1).

2. Experimental

2.1. General

All chemicals were purchased from Merck and Aldrich companies. The melting points of the prepared derivatives were measured by an electrothermal 9100 apparatus. Elemental analysis of the nanocatalyst was carried out by energy-dispersive X-ray (EDX) analysis recorded on Numerix JEOL-JDX. Fourier transform infrared (FT-IR) spectra were recorded on a Shimadzu 8400 S spectrometer using KBr pellets. X-ray diffraction (XRD) pattern of the nanocatalyst was recorded on an X-ray diffractometer (Bruker D8 Advance) and the morphology of prepared nanocatalyst was studied by SEM using VEGA2 TESCAN instrument.

2.2. Preparation of Magnetized Dextrin Nanocomposite

First, 2 mmol FeCl3.6H2O and 1 mmol FeCl2.4H2O were dissolved in 100 mL of distilled water, then the aqueous solution of 0.35 g dextrin in 25 mL distilled was added to the solution. The temperature of the resulting mixture was raised to 90 °C and stirred under a nitrogen atmosphere for 1 h. Later, NH4OH (25%) was added dropwise over 15 min to the stirring above suspension The reaction continued for about one hour. Finally, the black crude precipitate was collected by magnet, washed several times with distilled water and ethanol to remove non-reactive materials, and then dried at room temperature for 24 h to obtain magnetized dextrin nanocomposite.

2.3. General Procedure for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives

The mixture of hydrazine hydrate (2 mmol), ethyl acetoacetate (2 mmol), malononitrile (1 mmol), and aromatic aldehydes (1 mmol) were mixed together in the presence of 0.015 g of magnetized dextrin in ethanol and refluxed for appropriate time. The reaction progress was monitored by thin layer chromatography (TLC). Finally, after completion of the reaction, the catalyst was separated from the reaction mixture by an external magnet and high pure product was obtained by recrystallization of the crude precipitate in ethanol.

3. Results and Discussion

3.1. Characterization Magnetized Dextrin

Elemental analysis was employed to investigate the chemical composition of the magnetized dextrin. As can be seen in the Figure 2, the presence of C, O and Fe elements in the prepared nanocatalyst was confirmed by this analysis.
FT-IR spectra of magnetized dextrin (b) in comparison with dextrin (a) are observed in Figure 3. In the IR spectrum of dextrin, a broad absorption band at 3438 cm−1 is related to the stretching vibration of O–H bond which is abundant in dextrin structure, adsorption band at 2923 cm−1 is related to the stretching vibration of C–H bond, and the adsorption band at 1153 cm−1 is attributed to the asymmetric vibration of the glycosidic C–O–C bond. Comparison of FT-IR spectra of magnetized dextrin and dextrin showed that in the magnetic dextrin spectrum, in addition to observing the main adsorptions of dextrin, two new absorptions at 632 and 579 cm−1 appeared which is ascribed to the stretching vibrations of Fe–O bond of Fe3O4 MNPs [3].
The SEM image was used to show the morphology and particle size of the prepared nanocatalysts. As is shown in Figure 4, there are aggregation of spherical like particles which ascribed to Fe3O4 MNPs, present on the surface of dextrin. The average particle size of a magnetized dextrin is about 85 nm.
XRD analysis was used to study the crystalline structure of prepared nanocatalyst. As reported in the literature, XRD pattern of dextrin has two broad peaks signifying its amorphous nature [9]. The XRD patterns of magnetized dextrin and standard Fe3O4 MNPs were compared in Figure 5. The synthesized nanocomposite exhibited several peaks at 2θ = 17.5°, 30.1°, 35.5°, 37.9°, 57.4°, and 69.7° that are in accordance with the standard pattern of Fe3O4 MNPs with card no. JCPDS, 00-001-111.

3.2. Catalytic Application of the Magnetized Dextrin in the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives

The synthesis of dihydropyrano[2,3-c]pyrazole derivatives using some aromatic aldehydes in optimum condition was studied and in order to evaluate generality, and limitation of this protocol. As is observed in Table 1, all examined aromatic aldehydes with electron withdrawing and electron donating substitution produced the satisfying corresponding products.

4. Conclusions

Magnetized dextrin nanocomposite was synthesized using as a green, retrievable, and cost-effective catalyst for synthesis of biologically active of dihydropyrano[2,3-c]pyrazole derivatives. This procedure has advantages such as high efficiency products, mild reaction conditions, and easy separation of the product from the reaction mixture.


This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.


The authors gratefully acknowledge the partial support from the Research Council of the Iran University of Science and Technology.


  1. Baran, T.; Baran, N.Y.; Menteş, A. An easily recoverable and highly reproducible agar-supported palladium catalyst for Suzuki-Miyaura coupling reactions and reduction of o-nitroaniline. Int. J. Biol. Macromol. 2018, 115, 249–256. [Google Scholar] [CrossRef] [PubMed]
  2. Zare, E.N.; Lakouraj, M.M.; Kasirian, N. Development of effective nano-biosorbent based on poly m-phenylenediamine grafted dextrin for removal of Pb (II) and methylene blue from water. Carbohydr. Polym. 2018, 201, 539–548. [Google Scholar] [CrossRef] [PubMed]
  3. Maleki, A.; Hassanzadeh-Afruzi, F.; Varzi, Z.; Esmaeili, M.S. Magnetic dextrin nanobiomaterial: An organic-inorganic hybrid catalyst for the synthesis of biologically active polyhydroquinoline derivatives by asymmetric Hantzsch reaction. Mater. Sci. Eng. C 2020, 109, 110502. [Google Scholar] [CrossRef] [PubMed]
  4. Maleki, A.; Varzi, Z.; Hassanzadeh-Afruzi, F. Preparation and characterization of an eco-friendly ZnFe2O4@ alginic acid nanocomposite catalyst and its application in the synthesis of 2-amino-3-cyano-4H-pyran derivatives. Polyhedron 2019, 171, 193–202. [Google Scholar] [CrossRef]
  5. Hajizadeh, Z.; Maleki, A. Poly (ethylene imine)-modified magnetic halloysite nanotubes: A novel, efficient and recyclable catalyst for the synthesis of dihydropyrano [2,3-c] pyrazole derivatives. Mol. Catal. 2018, 460, 87–93. [Google Scholar] [CrossRef]
  6. Maleki, A.; Firouzi-Haji, R.; Hajizadeh, Z. Magnetic guanidinylated chitosan nanobiocomposite: A green catalyst for the synthesis of 1, 4-dihydropyridines. Int. J. Biol. Macromol. 2018, 116, 320–326. [Google Scholar] [CrossRef] [PubMed]
  7. Maleki, A.; Jafari, A.A.; Yousefi, S. Green cellulose-based nanocomposite catalyst: Design and facile performance in aqueous synthesis of pyranopyrimidines and pyrazolopyranopyrimidines. Carbohydr. Polym. 2017, 175, 409–416. [Google Scholar] [CrossRef] [PubMed]
  8. Bahrami, S.; Hassanzadeh-Afruzi, F.; Maleki, A. Synthesis and characterization of a novel and green rod-like magnetic ZnS/CuFe2O4/agar organometallic hybrid catalyst for the synthesis of biologically-active 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives. Appl. Organomet. Chem. 2020, 34, e5949. [Google Scholar] [CrossRef]
  9. Zare, E.N.; Lakouraj, M.M. Biodegradable polyaniline/dextrin conductive nanocomposites: Synthesis, characterization, and study of antioxidant activity and sorption of heavy metal ions. Iran. Polym. J. 2014, 23, 257–266. [Google Scholar] [CrossRef]
  10. Eivazzadeh-Keihan, R.; Taheri-Ledari, R.; Khosropour, N.; Dalvand, S.; Maleki, A.; Mousavi-Khoshdel, S.M.; Sohrabi, H. Fe3O4/GO@ melamine-ZnO nanocomposite: A promising versatile tool for organic catalysis and electrical capacitance. Colloids Surf. A Physicochem. Eng. Asp. 2020, 587, 124335. [Google Scholar] [CrossRef]
Figure 1. Chemical structure of dextrin.
Figure 1. Chemical structure of dextrin.
Chemproc 03 00101 g001
Scheme 1. Synthesis of dihydropyrano[2,3-c]pyrazoles derivatives.
Scheme 1. Synthesis of dihydropyrano[2,3-c]pyrazoles derivatives.
Chemproc 03 00101 sch001
Figure 2. EDX analysis of magnetized dextrin nanocatalyst.
Figure 2. EDX analysis of magnetized dextrin nanocatalyst.
Chemproc 03 00101 g002
Figure 3. FTIR spectra of dextrin and the magnetized dextrin nanocatalyst.
Figure 3. FTIR spectra of dextrin and the magnetized dextrin nanocatalyst.
Chemproc 03 00101 g003
Figure 4. SEM images of the magnetic dextrin nanocatalyst.
Figure 4. SEM images of the magnetic dextrin nanocatalyst.
Chemproc 03 00101 g004
Figure 5. XRD pattern of the magnetized dextrin nanocatalyst and standard Fe3O4.
Figure 5. XRD pattern of the magnetized dextrin nanocatalyst and standard Fe3O4.
Chemproc 03 00101 g005
Table 1. Synthesis of dihydropyrano[2,3-c]pyrazole using the magnetized dextrin nanocatalyst.
Table 1. Synthesis of dihydropyrano[2,3-c]pyrazole using the magnetized dextrin nanocatalyst.
EntryRProductYield a (%)Mp (°C)
14-Cl4a92232–235 [5]
23-NO24b90236–239 [5]
34-OMe4c85212–214 [5]
43-OMe4d89245 [10]
54-Me4e84193–195 [10]
a Isolated yield.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Amiri-Khamakani, Z.; Hassanzadeh-Afruzi, F.; Maleki, A. Magnetized Dextrin: Eco-Friendly Effective Nanocatalyst for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives. Chem. Proc. 2021, 3, 101.

AMA Style

Amiri-Khamakani Z, Hassanzadeh-Afruzi F, Maleki A. Magnetized Dextrin: Eco-Friendly Effective Nanocatalyst for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives. Chemistry Proceedings. 2021; 3(1):101.

Chicago/Turabian Style

Amiri-Khamakani, Zeinab, Fereshte Hassanzadeh-Afruzi, and Ali Maleki. 2021. "Magnetized Dextrin: Eco-Friendly Effective Nanocatalyst for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives" Chemistry Proceedings 3, no. 1: 101.

Article Metrics

Back to TopTop