β-Alanine-functionalized magnetic graphene oxide quantum dots: an efficient and recyclable heterogeneous basic catalyst for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 2,3-dihydroquinazolin-4(1H)-one derivatives

Article abstract of DOI:10.1002/aoc.5872

In this research, we report a novel synthesis of magnetic β-alanine-functionalized-graphene oxide quantum dots Fe₃O₄@GOQDs-N-(β-alanine) as a recyclable and eco-friendly heterogeneous nanocatalyst. The catalytic efficiency of these nanosheets was explored as a basic catalyst for a one-pot three-component synthesis of various 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 2,3-dihydroquinazolin-4(1H)-one derivatives. The reactions proceeded smoothly under mild and green conditions to afford the respected products in excellent yields. The structure of this newly fabricated catalyst was successfully confirmed by different analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, field emission-scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, and thermogravimetric analysis. The stability and recyclability of the catalyst were examined by performing the model reaction in six consecutive runs. The recovered catalyst from the first run was directly used for the next runs with no significant loss of catalytic activity.

Full text of DOI:10.1002/aoc.5872

Received: 10 March 2020
DOI: 10.1002/aoc.5872
Revised: 18 May 2020
Accepted: 19 May 2020
F U L L P A P E R
β-Alanine-functionalized magnetic graphene oxide
quantum dots: an efficient and recyclable heterogeneous
basic catalyst for the synthesis of 1H-pyrazolo[1,2-b]
phthalazine-5,10-dione and 2,3-dihydroquinazolin-4(1H)-one
derivatives
Masoud Khaleghi Abbasabadi
| Davood Azarifar
Department of Chemistry, Bu-Ali Sina
University, Hamedan, Iran
In this research, we report a novel synthesis of magnetic β-alanine-
functionalized-graphene oxide quantum dots Fe3O4@GOQDs-N-(β-alanine) as a
recyclable and eco-friendly heterogeneous nanocatalyst. The catalytic efficiency
of these nanosheets was explored as a basic catalyst for a one-pot three-
component synthesis of various 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and
2,3-dihydroquinazolin-4(1H)-one derivatives. The reactions proceeded smoothly
under mild and green conditions to afford the respected products in
excellent yields. The structure of this newly fabricated catalyst was successfully
confirmed by different analytical techniques such as Fourier transform infrared
spectroscopy, X-ray diffraction, field emission-scanning electron microscopy,
high-resolution transmission electron microscopy, energy-dispersive X-ray spec-
troscopy, vibrating sample magnetometry, and thermogravimetric analysis. The
stability and recyclability of the catalyst were examined by performing the
model reaction in six consecutive runs. The recovered catalyst from the first run
was directly used for the next runs with no significant loss of catalytic activity.
Correspondence
Masoud Khaleghi Abbasabadi,
Department of Chemistry, Bu-Ali Sina
University, Hamedan 65178, Iran.
Email: masoudkhaleghiabbasabadi@
gmail.com
K E Y W O R D S
1H-Pyrazolo[1,2-b] phthalazine-5,10-dione, 2,3-dihydroquinazolin-4(1H)-one, environmentally
friendly nanomagnetic sheets, heterogeneous basic catalyst, magnetic β-alanine-functionalized
graphene oxide quantum dots
1 | INTRODUCTION
industrial processes.[1–3] Multicomponent reactions have
attracted growing interest as useful synthetic strategy in
In recent years, the scientists have been extremely con-
cerned about the health and environmental problems
resulting from the use of harmful chemical reagents and
organic solvents. This environmental anxiety prompted
them to make significant efforts to develop more environ-
mentally friendly approaches such as multicomponent
reactions and recyclable catalysts to avoid harmful
organic solvents and reagents in chemical reactions and
the synthetic chemistry and pharmaceutical industry.[4–6]
In general, multicomponent reactions benefit from cer-
tain advantages such as waste prevention, energy effi-
ciency, yield improvement, and short reaction times.[3]
In the last few decades, a wide variety of nanoparticles
have been developed as powerful homogeneous and het-
erogeneous
catalysts.[7–9]Among
these,
magnetic
nanoparticles are the most important and practically useful
Appl Organomet Chem. 2020;e5872.
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© 2020 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.5872

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KHALEGHI ABBASABADI ≻AND AZARIFAR
classes of nanomaterials that demonstrate unique physical
and physicochemical properties. Nanometal oxides such
as Fe3O4, Fe2O3, ZnO, Al2O3, and TiO2, and hybrid
magnetic nanomaterials such as Cu@IA-SBA-15,
NiFe2O4@TiO2-DEAOSO3H, NiFe2O4@TiO2–ILPip, Fe3O4@OA
−PdNPs, and Fe3O4@SiO2–A–Pd (EDTA) are the most effec-
tive and frequently used nanoparticle catalysts in chemi-
cal reactions and other industrial fields.[9–13] These
nanometal oxides offer many advantages due to their
unique size and chemical properties such as high
surface area, oxidizing, reducing, and acid–base
propertieson their surfaces.[14,15] Moreover, carbon-
based nanomaterials have recently attracted significant
interest owing to their useful applications in different
areas such as environment, water, chemical industries,
and energy. Besides, many of these carbon-based
nanomaterials have found wide applications as solid
base nanocatalysts in chemical reactions due to their
environmental compatibility, recyclability, high stabil-
ity, and cost-effectiveness.[16–22] One of the most useful
and frequently used nanostructured carbon materials is
graphene and its different structural forms including
graphene oxide (GO). Nano GO is the oxidized form of
graphene with amazing properties such as low specific
weight, larger specific surface area, high mechanical sta-
bility, high benignity, and oxygen-carrying ability,
which has been widely used as an efficient catalyst in
synthetic chemistry or as a support for various homoge-
neous catalysts.[23] The presence of different oxygen
functionalities including carbonyl, hydroxyl, and epoxy
groups on the aromatic scaffold of GO allows the
graphene aromatic sheets to mediate ionic and nonionic
interactions with a wide range of molecules.[23] More-
over, it has been known that GO can act as an oxidant
and/or Lewis acid with high proficiency.[23]
between aldehydes, malononitrile, and phthalhydrazide
over different catalytic systems such as [bmim]Br,
triethylamine,
PhI(OAc)2.
Al-KIT-6,
NaHCO3,
InCl3,
and
[41–46]
Similarly, 2,3-dihydroquinazoline-
4(1H)-one derivatives have a wide range of biological
activities as antitumor, analgesic, diuretic, anticancer,
and herbicide agents.[47–51] In general, the methods
reported for the synthesis of 2,3-dihydroquinazolin-
4(1H)-one derivatives involve three-component conden-
sation reactions between aryl aldehydes, isatoic anhy-
dride, and malononitrile.[52–54] However, many of these
methods suffer from certain drawbacks such as lengthy
procedures, vigorous conditions, and low yields of the
products.[55,56] The broad range applications of
2,3-dihydroquinazoline-4(1H)-one and pyrazolo-fused
phthalazine derivatives as useful precursors in synthetic
organic and medicinal chemistry has accentuated the
need to develop more improved synthetic approaches for
scaffold manipulation of heterocyclic compounds con-
taining phthalazine and 2,3-dihydroquinazoline-4(1H)-
one moieties.
Following our ongoing efforts for the development of
more benign and efficient heterogeneous nanocatalysts
and their catalytic applications in organic transformation
reactions, including the synthesis of heterocyclic
compounds,[57–61] herein we report the novel synthesis of
magnetic β-alanine-functionalized GO quantum dot
(GOQD), Fe3O4@GOQD-N-(β-alanine), nanoparticles as
a novel catalyst. This magnetic Fe3O4@GOQD-N-(β-
alanine) nanoparticle was explored as an efficient,
recyclable, and sustainable catalyst for one-pot synthesis
1H-pyrazolo[1,2-b]phthalazine-5,10-diones (4a–i) and
2,3-dihydroquinazolin-4(1H)-ones (7a–h) (Scheme 1).
Another useful crystalline structure of graphene
nanoparticles is known as graphene quantum dots which
are composed of a few layers of graphene fragments, typi-
cally less than 10 nm in size. Graphene quantum dots
have attracted significant interest in recent years due to
their advantages, such as nontoxicity, good solubility in
water and organic solvents, cost-effective synthesizing
strategies, easy functionalizing ability, high surface area,
high thermal and chemical resistance, biocompatibility,
and stable photoluminescence.[24-37]
Among heterocyclic compounds of biological impor-
tance, pyrazolo-fused phthalazine derivatives are of sig-
nificant importance owing to their wide variety of
pharmacological activities including anticonvulsant,
vasorelaxant, cardiotonic, antimalarial, and antiplatelet
properties.[38–40] The general synthesis of 1H-
2 | EXPERIMENTAL
2.1 | General
Chemicals including natural flake graphite powder (325
mesh, 99.95%) were purchased from Sigma-Aldrich
(Munich, Germany) and used without further purifica-
tion. 1H nuclear magnetic resonance (NMR) and 13C
NMR spectra were measured for samples in CDCl3 or
DSMO-d6 using a 400-MHz Bruker AVANCE instrument
at 400 and 100 MHz, respectively, using Me4Si as internal
standard. The progress of the reactions was monitored by
thin-layer chromatography (TLC) on Silica Gel PolyGram
SIL G/UV 254 plates. Melting points were measured in
open capillary tubes using an electro thermal 9100 appa-
ratus. Fourier transform infrared (FT-IR) spectra were
recorded from KBr pellets using a Perkin Elmer Spectrum
65 FT-IR model instrument. The qualitative analysis of
pyrazolo[1,2-b]phthalazine-5,10-dione
derivatives
involves three-component condensation reactions

KHALEGHI ABBASABADI ≻AND AZARIFAR
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SCHEME 1 Synthesis of 1H-pyrazolo[1,2-b]
phthalazine-5,10-dione 4a–i and 2,3-
dihydroquinazolin-4(1H)-ones derivatives 7a–h using
Fe3O4@GOQDs-N-(β-alanine)
the Fe3O4@GOQDs-N-(β-alanine) nanosheets was per-
formed by scanning electron microscopy (SEM) using an
EM3200 microscope operated at 30-kV accelerating volt-
age, and high-resolution transmission electron micros-
copy performed on a Zeiss model EM10C-100 kv
instrument. The X-ray diffraction (XRD) analysis of the
synthesized GO, GOQDs, and Fe3O4@GOQDs-N-(β-ala-
nine) was conducted on a PANalytical X’Pert PRO X-Ray
Diffractometer instrument at room temperature. Energy-
dispersive X-ray (EDX) analysis of the prepared catalyst
was performed on a VG ESCALAB-200R spectrometer.
Magnetic measurement of the Fe3O4@GOQDs-N-(β-ala-
nine) nanomagnetic sheets was performed with a vibrat-
ing sample magnetometer (model LBKFB; Meghnatis
Daghigh Kavir Co, Iran) at room temperature.
Ultrasonication was performed in a 2200 ETH-SONICA
ultrasound cleaner with a frequency of 50 kHz.
dimethylformamide (DMF) as a reducing agent and sol-
vent and heated at 250 C for 6 hr. Then, the reaction
mixture was vacuum filtered using a 0.2-μm nylon mem-
brane. The dark solid GOQDs were obtained by
evaporating the solvent using a rotary evaporator and
dried at 60 ꢀC.
ꢀ
2.4 | Preparation of β-alanine-
functionalized Fe3O4-supported graphene
oxide quantum dot nanomagnetic sheets
2.4.1 | Acyl-chlorination of GOQDs
To 60 mL of thionyl chloride, GO (0.3 g) was added and
the mixture was stirred at 70 ꢀC under an argon
atmosphere for 24 hr. After completion of the reaction,
the dark solid acyl-chlorinated GOQDs form which were
centrifuged and washed with tetrahydrofuran (THF) four
times and dried under vacuum.
2.2 | Preparation of graphene oxide (GO)
GO was prepared via the modified Hummers method.[62,63]
According to this method, 1.25 g of natural graphite powder
was stirred in 62 mL of H2SO4 for 24 hr. Then, 7.5 g of
KMnO4 was slowly added into the mixture and stirred for
2.4.2 | Functionalization of graphene
oxide quantum dots (GOQDs) with β-
alanine
ꢀ
72 hr at 50 C. Afterward, the resulted mixture was poured
into a beaker containing 125 mL of ice. A solution of
12.5 mL H2O2 (30%) in at least 125 mL of deionized
(DI) water was added to the mixture after which the dark
brown color of the reaction mixture turned into bright yel-
low. Then, the final product was washed with DI water and
10% HCl solution, centrifuged repeatedly, and dried at oven.
About 1 g of β-alanine was added to 0.3 g of acyl-
chlorinated GOQDs. Next, the resulting mixture was
ꢀ
refluxed at 120 C for 72 hr under an argon atmosphere.
The reaction mixture was then washed with DI water
three successive times to obtain a pure dark powder of
GOQD-N-(β-alanine).
2.3 | Synthesis of graphene oxide
quantum dots (GOQDs)
2.4.3 | Nano magnetization of β-alanine-
functionalized graphene oxide quantum
dots
GOQDs were prepared according to a simple procedure
reported by Shi et al.[64] Freshly synthesized GO (0.30 g),
as described earlier, was treated with 60 mL of N,N-
The Fe3O4@GOQDs-N-(β-alanine) was prepared by co-
precipitation of FeCl2Á4H2O and FeCl3Á6H2O in the

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KHALEGHI ABBASABADI ≻AND AZARIFAR
presence of β-alanine-grafted GOQDs following a modi-
fied procedure reported by Kassaee et al.[65] First, a 2:1
molar ratio aqueous solution of FeCl3Á6H2O and
FeCl2Á4H2O was prepared. Second, 20 mg of freshly
prepared GOQDs-N-(β-alanine) in 20 mL of DI water
was ultrasonicated for 30 min. To this mixture was
added 25 mL of a previously prepared solution of
FeCl3 (400 mg) and FeCl2 (150 mg) in DI water
(20 mL) at room temperature. The percent weight ratio
of FeCl3 to GO (mFeCl3:mGOQDs) in the prepared mix-
ture was found to be 20:1. Lastly, the pH value of the
mixture was increased to 11 by adding a 30% aqueous
solution of ammonia (15 mL), and the resulting mix-
ture was stirred at 75 ꢀC for 30 min. The resulted
black powder of Fe3O4@GOQD-N-(β-alanine) was cen-
trifuged, washed six times with DI water, and dried
at 65 ꢀC to obtain pure Fe3O4@GOQD-N-(β-alanine)
(565 mg).
(0.01 g) was added, and the mixture was stirred at room
temperature for an appropriate time (Table 4). After com-
pletion of the reaction, as monitored by TLC, the reaction
mixture was diluted with hot ethanol (15 mL), and stirred
for 3 min. The catalyst was isolated magnetically using
an external magnet. The remaining mixture was filtered
and the supernatant liquid was evaporated to leave the
crude product which was purified by recrystallization
from absolute EtOH. All the synthesized products 7a–h
are known compounds which are characterized by their
physical properties and spectral (FT-IR, 1H NMR,
13C NMR) analyses, and compared with the reported
corresponding data (Table 4).
3 | SELECTED DATA
3.1 | 3-Amino-1-phenyl-5,10-dioxo-
5,10-dihydro-1H-pyrazolo[1,2-b]
phthalazine-2-carbonitrile (4a)
2.5 | Typical procedure for the synthesis
of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione
derivatives
MP 274–276 C; FT-IR (KBr) ν (cm−1): 3362, 3261, 3192,
ꢀ
1
3035, 2198, 1681, 1660, 1605 1568, 1439, 1383 (C–N); H
NMR (90 MHz, dimethyl sulfoxide [DMSO]-d6): δ 6.12
(s, 1H, CH), 7.37–8.05 (m, 11H, Ar–H and NH2). 13C
NMR (75 MHz, DMSO-d6): δ 61.4, 62.9, 116.0, 126.6,
126.7, 127.2, 128.2, 128.5, 128.6, 128.7, 129.1, 133.7, 134.6,
138.4, 150.6, 153.6 ppm.
To the mixture of aryl aldehyde (1 mmol), phthalhydrazide
(0.162 g, 1 mmol), and malononitrile (0.066 g, 1 mmol) in
DI water (5 mL), the catalyst Fe3O4@GOQDs-N-(β-alanine)
(0.01 g) was added, and the mixture was stirred at room
temperature for an appropriate time (Table 3). After com-
pletion of the reaction, as monitored by TLC, the resulting
reaction mixture was diluted with ethanol (15 mL), and
stirred for 15 min. Then, the catalyst was isolated in
an external magnetic field. The remaining insoluble
phthalhydrazide was removed by filtration, and the
supernatant liquid was evaporated under reduced pressure.
The remaining crude product was washed with acetone
and 10% NaHCO3 solution and recrystallized from ethyl
acetate/n-hexane (5:7) to yield the reasonably pure product.
All the synthesized products 4a–i are known compounds
which are characterized by their melting points and spec-
3.2 | 3-Amino-1-(2,3-dichlorophenyl)-
5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]
phthalazine-2-carbonitrile (4e)
MP 262–264 C; FT-IR (KBr) ν (cm−1): 3373, 3238, 3178,
ꢀ
2211, 1683, 1659, 1603, 1566, 1415, 1380. 1H NMR
(400 MHz, DMSO-d6): 6.30 (1H, s, CH), 7.63–8.37 (m, 9H,
Ar–H and NH2) ppm. 13C NMR (100 MHz, DMSO-d6): δ
60.6, 62.5, 116.3, 122.2, 123.8, 127.1, 127.7, 128.7, 129.3,
130.7, 134.2, 134.3, 135.1, 148.3, 151.5, 154.3, 157.2 ppm.
1
tral (FT-IR, H NMR, and 13C NMR) analyses and com-
pared with the corresponding reported data (Table 3). In
addition, the characterization data for the selected products
are available online (see supporting information).
3.3 | 3-Amino-1-(4-methoxyphenyl)-
5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]
phthalazine-2-carbonitrile (4g)
−1
ꢀ
2.6 | General procedure for the synthesis
of 2,3-dihydroquinazolin-4(1H)-one
derivatives
MP 238–241 C; FT-IR (KBr) ν (cm ): 3373, 3267, 2192,
1665, 1603, 1584, 1417, 1382; 1H NMR (400 MHz,
DMSO-d6): δ 3.80 (s, 3H, OCH3), 6.15 (s, 1H, CH),
6.95–8.31 (m, 10H, Ar–H and NH2) ppm. 13C NMR
(100 MHz, DMSO-d6): δ 55.1, 61.3, 62.6, 113.8, 116.1,
125.1, 126.6, 127.2, 128.5128.7, 130.1, 132.5, 133.7, 134.6,
150.6, 153.6, 156.6, 159.2 ppm.
To a mixture of aryl aldehyde (1.1 mmol), isatoic anhy-
dride (0.163 g., 1 mmol), and arylamine (1 mmol) in DI
water (5 mL), the catalyst Fe3O4@GOQDs-(β-alanine)

KHALEGHI ABBASABADI ≻AND AZARIFAR
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3.4 | 3-Amino-5,10-dioxo-1-(pyridin-4-yl)-
5,10-dihydro-1H-pyrazolo[1,2-b]
phthalazine-2-carbonitrile (4i)
1178, 1024, 1032, 988, 838, 788, 740, 582. 1H NMR
(400 MHz, DMSO-d6) δ: 3.71 (s, 1H, OCH3), 6.64 (s, 1H, CH),
6.61–7.77 (m, 12H, H–Ar, NH) ppm. 13C NMR (125 MHz,
DMSO-d6) δ: 55.68, 55.76, 71.55, 114.5, 114.9, 115.01, 116.8,
118.2, 127.1, 127.3, 128.8, 129.8, 131.1, 132.7, 133.1, 134.3, 140.2,
146.3, 158.1, 162.6 ppm.
MP 263–266 C; FT-IR (KBr) ν (cm−1): 3388, 3285, 2198,
ꢀ
1
1681, 1664, 1604, 1579, 1441, 1384, H NMR (400 MHz,
DMSO-d6): δ 6.21 (s, 1H, CH), 7.57–8.64 (m, 10H, Ar–H
and NH2) ppm. 13C NMR (100 MHz, DMSO-d6): δ 60.1,
61.7, 115.7, 121.3, 126.7, 127.2, 128.3, 128.9, 133.8, 134.6,
147.1, 149.9, 150.9, 153.7, 156.7 ppm.
4 | RESULTS AND DISCUSSION
4.1 | Characterization of the catalyst
Fe3O4@GOQDs-N-(β-alanine)
nanomagnetic sheets
3.5 | 2,3-Dihydro-2-(4-methoxyphenyl)-3-p-
tolylquinazolin-4(1H)-one (7a)
In continuation of our efforts to develop green and to
achieve clean recovery of the heterogeneous catalyst,
herein we synthesized the hitherto unreported mag-
netic β-alanine-functionalized GOQDs Fe3O4@GOQDs-
N-(β-alanine) as a new nanomagnetic catalyst for the
synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione
and 2,3-dihydroquinazolin-4(1H)-one derivatives. As
depicted in Scheme 2, GO was first prepared by the
modified Hummers method as previously reported.[62,63]
In the next step, GOQDs were synthesized by a simple
process using freshly synthesized GO. GO was treated
MP 207–210 ꢀC; IR (KBr, ν, cm−1): 3295, 2923, 1637,
1609, 1513, 1456, 1391, 1299, 1246, 1159, 1030, 822, 786,
1
754, 936, 834, 759. H NMR (400 MHz, DMSO-d6) δ: 2.2
(s, 3H, CH3), 3.67 (s, 1H, OCH3), 6.15 (s, 1H, CH),
6.68–7.73 (m, 13H, H–Ar and NH) ppm.
3.6 | 2-(4-Methylphenyl)-
3-(4-chlorophenyl)-2,3-dihydroquinazolin-
4(1H)-one (7c)
[64]
ꢀ
with DMF and heated at 250 C for 6 hr.
The freshly
MP 257–260 C; IR (KBr, ν, cm −1): 3295, 2923, 1637,
prepared GOQDs were acyl chlorinated by treatment
with thionyl chloride followed by nucleophilic reaction
with β-alanine under reflux condition. Finally, the
resulting GOQDs-N-(β-alanine) were nano-magnetized
by co-precipitation of ferrous (Fe2+) and ferric (Fe3+) ions
in the presence of the resulting aminated GOQDs
(Scheme 2).[65]
ꢀ
1609, 1513, 1456, 1391, 2246, 1150, 1105, 1030, 822, 766,
1
754, 602. H NMR (400 MHz, DMSO-d6) δ: 2.27 (s, 3H,
CH3), 6.26 (s, 1H, CH), 6.74–7.72 (m, 13H, Ar–H and
NH) ppm. 13C NMR (125 MHz, DMSO-d6) δ: 20.59, 72.25,
114.7, 115.03, 117.48, 126.5, 127.9, 128.3, 128.4, 128.9,
130.02, 133.8, 137.3, 137.7, 139.5, 146.6, 162.3 ppm.
The structure of the newly prepared nanomagnetic
catalyst was established by performing various analyti-
cal methods such as FT-IR spectroscopy, XRD analysis,
field emission-scanning electron microscopy (FE-SEM),
high-resolution transmission electron microscopy, ther-
mogravimetric analysis (TGA), EDX spectroscopy, and
vibrating sample magnetometry (VSM) analysis.
3.7 | 3-(4-Chlorophenyl)-2-phenyl-
2,3-dihydroquinazolin-4(1H)-one (7f)
MP 215–218 ꢀC; IR (KBr, ν, cm−1): 3301, 3058, 2814,
1638, 1609, 1591, 1490, 1386, 1315, 1090, 1015, 877, 830,
520. 1H NMR (90 MHz, CDCl3) δ: 6.83 (s, 1H, CH),
7.36–7.78 (m, 14H, H–Ar, NH) ppm. 13C NMR (100 MHz,
DMSO-d6) δ: 72.4, 114.7, 114.9, 117.5, 126.6, 127.9,
128.05, 128.4, 128.5, 128.6, 130.1, 133.9, 139.4, 140.2,
146.6, 162.3 ppm.
The FT-IR spectra of the GO, GOQDs, GOQDs-N-(β-
alanine), and Fe3O4@GOQDs-N-(β-alanine) nanomagnetic
sheets presented in Figure 1 are compared. In these
compounds, the O–H stretching vibration due to the
carboxylic, hydroxy, and enolic groups present in the
GO unit is observed in the range 2750–3450 cm−1
.
The peaks at 1056, 1620, and 1717 cm−1 shown in the
spectrum of GO are assigned to the stretching vibra-
tions of C–O, C=C, and C=O groups, respectively.[71]
In addition, the characteristic peak that appeared at
1388 cm−1 in the spectra of the GO (Figure 1b–d) can
be attributed to the asymmetric stretching vibration of
the C–O–C bond related to the epoxide groups.
3.8 | 2-(2,3-Dichlorophenyl)-
3-(4-methoxyphenyl)-
2,3-dihydroquinazolin-4(1H)-one (7h)
MP 257–259 ꢀC; IR (KBr, ν, cm−1): 3419, 3284, 3004,
2964, 2631, 1634, 1609, 1588, 1480, 1426, 1317, 1248,

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KHALEGHI ABBASABADI ≻AND AZARIFAR
SCHEME 2 Synthetic route of Fe3O4@GOQDs-N-(β-alanine)
Similarity between the infrared spectra of GO (1a)
and GOQDs (1b) indicates that the surface of GO has
remained intact during the synthesis of GOQDs in the
presence of DMF. This result combined with the TEM
analysis clearly confirmed the successful synthesis of
GOQDs.[62] The peak at 1161 cm−1 in Figures 1c and 2d
can be attributed to the stretching vibration of the amino
C–N bond formed by amidation or amination of the
GOQDs sheets with the β-alanine group. In addition, the
characteristic stretching vibrations shown at 3235 and
3236 cm−1 in the spectra of the β-alanine-functionalized
GO (Figure 1c) and the Fe3O4@GOQDs-N-(β-alanine)
(Figure 1d), respectively, correspond to the N–H bond
stretching vibration.[18,64,72–74] The stretching vibrations
of the Fe–O bond were observed at 480 and 619 cm−1 in
the spectrum of the Fe3O4@GOQDs-N-(β-alanine)
nanomagnetic sheets (Figure 1d).[75,76] It has been shown
that the stretching frequency of the carboxylic group at
1716 cm−1 for the GO has been shifted to a lower fre-
quency at 1622 cm−1 for the Fe3O4-magnetized GO. These
results demonstrated that the GOQDs were successfully
functionalized with β-alanine groups as supported by the
magnetic Fe3O4 group.[75–78]
The crystalline nature and size of the GO,
Fe3O4@GOQDs-N-(β-alanine) (before it is used in the
reaction), and Fe3O4@GOQDs-N-(β-alanine) (recovered

KHALEGHI ABBASABADI ≻AND AZARIFAR
7 of 20
FIGURE 1 Comparative Fourier transform
infrared spectra for (a) GO, (b) GOQDs,
(c) GOQDs-N-(β-alanine), and
(d) Fe3O4@GOQDs-N-(β-alanine). GO, graphene
oxide; GOQD, graphene oxide quantum dot
illustrated in Figures 2a,b. The XRD pattern of the GO
illustrates mainly the intensive Braggs peaks at
2θ = 11.95ꢀ and 42.45ꢀ corresponding to the oxygen func-
tional groups which are intercalated between graphene
sheets in the course of oxidation.[78] These peaks are
related to the corresponding indices (002) and (100),
respectively. As evident in the XRD pattern of
Fe3O4@GOQDs-N-(β-alanine) (Figure 2b), there is a
wide-angle peak belonging to the (002) planes of
Fe3O4@GOQDs-N-(β-alanine).[78] The peak at 2θ = 11.8ꢀ
exhibited by GO has been significantly shifted to about
2θ = 24ꢀ as a result of amidation and magnetization with
Fe3O4. However, the existence of this peak at about
2θ = 24ꢀ agrees well with the presence of oxygen func-
tionalities even after functionalization and magnetization
of GO. The positions and relative intensities of all the
peaks shown at 2θ = 30.39ꢀ, 35.74ꢀ, 43.36ꢀ, 57.31ꢀ, and
62.93ꢀ in the XRD pattern of Fe3O4@GOQDs-N-(β-ala-
nine) are in compliance with the standard XRD pattern
of magnetite Fe3O4 (JCPDS Card No. 79–0417).[79] These
FIGURE 2 X-ray diffraction patterns of (a) GO,
(b) Fe3O4@GOQDs-N-(β-alanine) (before catalytic reaction), and
(c) Fe3O4@GOQDs-N-(β-alanine) (recovered after the third run).
GO, graphene oxide; GOQD, graphene oxide quantum dot
after the third run) nanomagnetic sheets were deter-
mined by XRD analysis. The XRD patterns of the GO and
the
prepared
Fe3O4@GOQDs-N-(β-alanine)
are

8 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR
five characteristic peaks revealing a crystalline cubic
structure for iron oxide phase are related to their
corresponding faces (220), (311), (400), (511), and (440),
respectively. This implies that the GO films were success-
we used the TEM images of the GOQDs (Figure 4) to
observe the numbers of GOQDs clusters and the distri-
bution of GOQDs. The FE-SEM images displayed in
Figure 3 indicated that Fe3O4@GOQD-N-(β-alanine) is
composed of wrinkled thin films closely associated with
each other to form disordered solids and randomly
accumulated. Moreover, the FE-SEM image of the
Fe3O4@GOQDs-N-(β-alanine) catalyst (Figure 3c) indi-
cated that the Fe3O4 nanoparticles exhibit a regularly
spherical morphology on GOQDs-N-(β-alanine) which
are made up of nano-sized films.[65]
Transmission electron microscopy (TEM) was used to
study the structure, size, and distrubtion of the prepared
GOQDs nanoparticles. Figure 4a–c shows the TEM
images of GOQDs in three different scales and Figure 4d
shows the particle size distrubtion. In these images the
number of GOQDs clusters was observed and it is
fully grafted with β-alanine groups and magnetized with
[79–81]
Fe3O4.
Figure 2c shows the XRD pattern of
Fe3O4@GOQDs-N-(β-alanine) after the third recovery
run. From Figure 2b,c, it can be observed that the struc-
ture of the Fe3O4@GOQDs-N-(β-alanine) did not change
during the catalytic reaction and recovery process.
The morphology and particle size of the GO, GOQDs,
and Fe3O4@GOQDs-N-(β-alanine) nanomagnetic parti-
cles were studied by FE-SEM (Figure 3). As revealed
from the comparison between the FE-SEM patterns of
the naked GO and GOQDs, no prominent change in the
morphology of GO films has occurred because of cutting
by DMF. Nevertheless, to analyze the GOQDs clusters
FIGURE 3 Field emission scanning electron microscopy images of (a) GO, (b) GOQDs, (c) GOQD-N-(β-alanine), and
(d) Fe3O4@GOQDs-N-(β-alanine). GO, graphene oxide; GOQD, graphene oxide quantum dot

KHALEGHI ABBASABADI ≻AND AZARIFAR
9 of 20
FIGURE 4 Transmission electron microscopy images of (a–c) graphene oxide quantum dots and (d) particle size distribution
indicated that the distribution of GOQDs was obviously
uniform and the average diameter estimated to be
1–11 nm. The results obtained from the TEM images of
GOQDs indicated that the GO with larger size was
successfuly converted to GOQDs.[82]
Figure 5 presents the FE-SEM and TEM images of
Fe3O4@GOQDs-N-(β-alanine) sample obtained after
the third recycle run. It is clearly observed that the
morphology and structure of Fe3O4@GOQDs-N-(β-ala-
nine) have not changed during the recovery process.
The elemental composition of GOQDs, GOQDs-N-(β-
alanine), and Fe3O4@GOQDs-N-(β-alanine) and the mass
percentages of the corresponding elements were deter-
mined by EDX analysis. The spectra obtained from the
EDX analysis of GOQDs, GOQDs-N-(β-alanine), and
Fe3O4@GOQDs-N-(β-alanine) are illustrated in Figures 6a
and 5b,c. According to Figure 6, the existence of the
expected elemental components is verified for the
graphene quantum dots GOQDs-N-(β-alanine) (C, O, N)
and Fe3O4@GOQDs-N-(β-alanine) (C, O, N, Fe). These
results provide further evidence for successful grafting of
β-alanine group onto the GOQDs films and magnetiza-
tion with Fe3O4 nanoparticle.
Figure 7 shows the EDX and FT-IR spectra of the
Fe3O4@GOQDs-N-(β-alanine) sample obtained after th
third recycle run. A comparison between EDX and FT-IR
spectra after the thrid recycle confirms that elemental
components and the structure of the Fe3O4@GOQDs-N-
(β-alanine) did not change during the catalytic reaction
and recovery process. These results prove that the catalyst
can be reused several consecutive times without any
noticeable change in its structure.

10 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR
FIGURE 5 (a) Scanning electron microscopy images of Fe3O4@GOQDs-N-(β-alanine) (recovered after the third run), and
(b) transmission electron microscopy Fe3O4@GOQDs-N-(β-alanine) (recovered after the third run). GOQD, graphene oxide quantum dot
FIGURE 6 Energy-dispersive X-ray spectra for (a) GOQDs, (b) GOQDs-N-(β-alanine), and (c) Fe3O4@GOQDs-N-(β-alanine). GOQD,
graphene oxide quantum dot

KHALEGHI ABBASABADI ≻AND AZARIFAR
11 of 20
FIGURE 7 (a) Comparative energy-dispersive X-ray spectra of Fe3O4@GOQDs-N-(β-alanine) (recovered after the third run) and
(b) Fourier transform infrared Fe3O4@GOQDs-N-(β-alanine) (recovered after the third run). GOQD, graphene oxide quantum dot
ꢀ
The magnetic behavior of the prepared Fe3O4@GOQDs-
N-(β-alanine) nanocatalyst was determined using VSM at
300 K as shown in Figure 8. According to the typical plot of
magnetization versus applied magnetic field of Fe3O4@-
GOQDs-N-(β-alanine) shown in this figure, the saturation
magnetization (Ms) amount of Fe3O4@GOQDs-N-(β-alanine)
was found to be 50 emu g–1.[7] This saturation magnetization
value clearly confirms the super-paramagnetic property of
the Fe3O4@GOQDs-N-(β-alanine) nanocatalyst, which
allows it to be efficiently separated from the reaction mixture
simply by using an external magnetic field.
TGA and differential thermal analysis (DTA) were
carried out on the prepared GO and Fe3O4@GOQDs-N-
(β-alanine) nanosheets to show their thermal decomposi-
tion profiles (Figures 9 and 10). According to these
figures, the thermal stability of Fe3O4@GOQDs-N-(β-ala-
nine) is higher as compared with that of GO. The GO
experiences weight loss in two steps. The first weight loss
(18 wt%) of the GO occurs up to 98 C, and is primarily
due to remaining water. The second significant weight loss
(about 71.78 wt%) occurs around 215 ꢀC, and could be due
to the decomposition of oxygen-containing groups.[65,83,84]
According to the TGA and DTA thermograms
obtained for Fe3O4@GOQDs-N-(β-alanine), the weight
loss process of the catalyst could be divided into three
stages (Figure 10). As shown in Figure 10, the first
weight loss (6 wt%) of Fe3O4@GOQDs-N-(β-alanine)
occurs below 118 ꢀC and is related to the thermal
desorption of the adsorbed water.ꢀ The second weight
loss (8 wt%) occurs at around 212 C, and is attributed
to the decomposition of oxygen-containing groups in
GO. The thirdꢀ and fourth weight losses occur in the
range 245–605 C, and are possibly due to the complete
removal of the organic residue and decomposition of β-
alanine groups on the surface of GOQDs.[65,83,84] These
results provide further evidence for successful func-
tionalization of β-alanine onto the surface of GO as well
as the magnetization with Fe3O4 nanoparticles.
4.2 | Catalytic activity of Fe3O4@GOQDs-
N-(β-alanine) nanoparticles for the
synthesis of 1H-pyrazolo[1,2-b]phthalazine-
5,10-dione and 2,3-dihydroquinazolin-
4(1H)-ones
In order to evaluate the catalytic potential of the newly
prepared Fe3O4@GOQDs-N-(β-alanine) as a heteroge-
neous nanocatalyst in organic transformations, we chose
to examine its activity in one-pot synthesis of 1H-
pyrazolo[1,2-b]phthalazine-5,10-dione derivatives from a
three-component reaction between aromatic aldehydes,
malononitrile, and phthalhydrazide and also one-pot syn-
thesis of 2,3-dihydroquinazolin-4(1H)-one derivatives
FIGURE 8 Vibrating sample magnetometry image of
Fe3O4@GOQDs-N-(β-alanine)

12 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR
FIGURE 9 Thermogravimetric analysis
(TGA) and differential thermal analysis (DTA)
curves of GO
FIGURE 10 Thermogravimetric analysis
(TGA) and differential thermal analysis (DTA)
curves of Fe3O4@GOQDs-N-(β-alanine)
from a three-component reaction between aryl aldehydes,
isatoic anhydride, and malononitrile.
Similarly, to establish the conditions for the
synthesis of 2,3-dihydroquinazolin-4(1H)-ones, we
selected the one-pot condensation reaction between
4-chlorobenzaldehyde, malononitrile, and isatoic anhy-
dride as a model reaction (Scheme 4). Initially, the effects
of temperature and solvent on the reaction were studied
by varying the temperature and solvent (H2O, EtOH,
DMF, and THF) using the same amount of the catalyst
(10 mg). According to the experimental results summa-
rized in Table 2, the best result in terms of the reaction
rate and yield of the corresponding product was obtained
when the reaction was carried out in H2O at room tem-
perature using the catalyst loading of 10 mg (Entry 2).
Finally, the importance of the catalyst presence in the
reaction was approved by conducting the reaction in the
absence of the catalyst under optimized conditions that
resulted in a trace amount of the expected product after a
prolonged reaction time (Entry 14).
Initially, we carried out the reaction for the
synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones
by selecting the one-pot condensation reaction between
3-nitrobenzaldehyde, malononitrile and phthalhydrazide
as model reaction (Scheme 3). To specify the optimal
reaction conditions, the reaction parameters such as cata-
lyst loading, solvent (H2O, EtOH, DMF, THF), and reac-
tion temperature were screened. According to the
experimental results summarized in Table 1, the best
results in terms of the reaction rate and yield of the
product 1H-pyrazolo[1,2-b]phthalazine-5,10-dione were
obtained when the reaction was carried out in H2O as a
solvent, with catalyst loading of 10 mg, and at room
temperature (Entry 2). The catalytic role of the
Fe3O4@GOQDs-N-(β-alanine) nanoparticles in the model
reaction was substantiated by conducting the reaction in
the absence of the catalyst and noting that no detectable
amount of the respective product was produced after a
long reaction time (Entry 14).
To investigate the scope and general applicability of
the reaction, a series of variously substituted aldehydes
were reacted under the aforementioned optimized

KHALEGHI ABBASABADI ≻AND AZARIFAR
13 of 20
TABLE 1
Screening the reaction parameters for the model synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dionea
Entry
Catalyst loading (mg)
Solvent
No solvent
H2O
Temperature (ꢀC)
Time (min)
Yieldb (%)
1
10
25
25
90
15
20
40
30
15
15
20
25
30
25
25
35
120
Trace
94
2
10
3
10
EtOH
THF
25
60
4
10
25
35
5
10
DMF
H2O
25
45
6
10
50
92
7
10
H2O
80
89
8
10
H2O
100
Reflux
25
90
9
10
H2O
85
10
11
12
13
14
5
H2O
88
20
H2O
25
90
30
H2O
25
90
40
H2O
25
85
No catalyst
H2O
25
Trace
aConditions: 3-nitrobenzaldehyde (1.1 mmol), phthalhydrazide (1 mmol), malononitrile (1 mmol), solvent (5 mL).
bIsolated yields.
THF, tetrahydrofuran; DMF, N,N-dimethylformamide.
conditions to obtain the corresponding 1H-pyrazolo[1,2-b]
phthalazine-5,10-diones 4a–i and 2,3-dihydroquinazolin-
4(1H)-ones 7a–h (Schemes 5 and 6). The experimental
results summarized in Tables 3 and 4 clearly reveal that
all the aldehydes carrying either electron-donating or
electron-withdrawing substituents react smoothly to afford
the desired products 4a–i and 7a–h in excellent yields
(90%–98%) in short reaction times (10–20 min) in H2O as a
green solvent. All the products are known compounds
which are characterized by their melting points and spec-
presented catalyst Fe3O4@GOQDs-N-(β-alanine) in the
reactions is more efficient for the synthesis of 1H-
pyrazolo[1,2-b]phthalazine-5,10-dione
and
2,3-dihydroquinazolin-4(1H)-one derivatives. Therefore,
the present method could be considered as a suitable alter-
native method for the synthesis of 1H-pyrazolo[1,2-b]
phthalazine-5,10-diones and 2,3-dihydroquinazolin-4(1H)-
one derivatives as well.
1
tral (FT-IR, H NMR, 13C NMR) analysis and compared
4.3 | Proposed catalytic reaction
with the reported data. The characteristic data for some
selected products are presented in the “Experimental”
section.
As summarized in Table 5, the experimental data
(yield, time, reaction conditions) from this work are com-
pared with those reported by other research groups in the
literature on the catalytic synthesis of 1H-pyrazolo[1,2-b]
phthalazine-5,10-diones and 2,3-dihydroquinazolin-
4(1H)-ones. From this comparison it becomes evident
that our method is more green and simple and the newly
mechanisms
The presence of different oxygen functionalities including
carbonyl, hydroxyl, and epoxy groups on the aromatic
scaffold of GO allows the graphene act as acids. Also, β-
Alanine group act as base that strongly catalyze reactions.
In addition, the presence of Fe3O4 increases the magnetic
properties of the catalyst and promotes organic reactions
that allows it to be simply separated from the reaction
mixture by using an external magnetic field. A reasonable

14 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR
TABLE 2
Screening the reaction parameters for the model synthesis of 2,3-dihydroquinazolin-4(1H)-onesa
Entry
Catalyst loading (mg)
Solvent
No solvent
H2O
Temperature (ꢀC)
Time (min)
Yieldb (%)
1
10
25
25
60
20
75
75
90
20
20
15
15
25
20
25
30
90
Trace
95
2
10
3
10
EtOH
THF
25
50
4
10
25
20
5
10
DMF
H2O
25
42
6
10
50
92
7
10
H2O
80
85
8
10
H2O
100
Reflux
25
80
9
10
H2O
75
10
11
12
13
14
5
H2O
75
20
H2O
25
80
30
H2O
25
90
40
H2O
25
85
No catalyst
H2O
25
Trace
aConditions: 4-Chlorobenzaldehyde (1.1 mmol), isatoic anhydride (1 mmol), p-toluidine (1.1 mmol), solvent (5 mL).
bIsolated yields.
THF, tetrahydrofuran; DMF, N,N-dimethylformamide.
mechanism to explain the three-component condensation
reactions between aldehydes, malononitrile, and
phthalhydrazide in the presence of Fe3O4@GOQDs-N-(β-
alanine) as a basic catalyst is depicted in Scheme 7. The
initial step involves deprotonation of malononitrile pro-
moted by the Fe3O4@GOQDs-N-(β-alanine) catalyst act-
ing as a Lewis base. Following deprotonation of
malononitrile, the resulting malononitrile anion reacts
with the protonated aldehyde to produce the α-
cyanocinnamonitrile intermediate (I). Afterward,
Fe3O4@GOQDs-N-(β-alanine)-induced enolization of
phthalhydrazide occurs to produce its enol form which
undergoes nucleophilic addition to the intermediate (I).
Finally, the resulting adduct (II) undergoes subsequent
catalyst-activated intramolecular cyclization to afford the
expected products 4a–i.
Fe3O4@GOQDs-N-(β-alanine) catalyst to undergo nucleo-
philic addition to the isatoic anhydride to form the intermedi-
ate (I) as described in Scheme 8. Then, the resulting
intermediate adduct (II) undergoes nucleophilic addition to
the aldehyde to yield the intermediate adduct (III). Finally,
the resulting intermediate (II) undergoes the subsequent
catalyst-activated intramolecular cyclization to afford the
expected 2,3-dihydroquinazolin-4(1H)-one products 7a–h.
4.4 | Catalyst recyclability
The potential recyclability of the catalyst Fe3O4@GOQDs-
N-(β-alanine) was studied for the model reaction between
3-nitrobenzaldehyde, malononitrile, and phthalhydrazide
under the optimized conditions successively applied for
several fresh runs. The possible diminution of the catalytic
activity in terms of the reaction yield was examined by
magnetically separating the catalyst nanoparticles from
the reaction mixture, washing with hot ethanol, and
reusing it in several consecutive fresh runs. The results
As depicted in Scheme 8, a similar mechanism can
be postulated for the three-component synthesis of
2,3-dihydroquinazolin-4(1H)-one derivatives in the presence
of Fe3O4@GOQDs-N-(β-alanine) as a basic catalyst. In this
mechanism, the amine was activated by the

KHALEGHI ABBASABADI ≻AND AZARIFAR
15 of 20
TABLE 3
Synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives catalyzed by Fe3O4@GOQDs-N-(β-alanine)a
MP (ꢀC)
Reported
[53,66–70,85]
Entry
Ar
Product
Time (min)
Yieldb (%)
TONc
12.4
12.6
12.8
12.6
12.2
12.1
12.4
12.9
11.8
TOFd (min−1
0.82
)
Found
1
2
3
4
5
6
7
8
9
C6H5
4a
4b
4c
4d
4e
4f
15
10
20
10
10
15
15
20
10
94
96
97
96
93
92
94
98
90
274–276
269–271
254–256
250–252
262–264
264–267
238–241
269–272
263–266
276–278
270–272
255–256
259–262
261–263
265–267
240–242
269–271
265–266
4-ClC6H4
4-MeC6H4
2-ClC6H4
2,3-Cl2C6H4
4-BrC6H4
4-MeOC6H4
3-NO2C6H4
4-C5H4N
1.26
0.64
1.26
1.22
0.8
4g
4h
4i
0.82
0.64
1.18
aConditions: aldehyde (1.1 mmol), phthalhydrazide (1 mmol), malononitrile (1.1 mmol), H2O (5 mL), catalyst (10 mg), room temperature.
bIsolated yields.
cTurnover number.
dTurnover frequency.
TABLE 4
Synthesis of 2,3-dihydroquinazolin-4(1H)-ones derivatives catalyzed by Fe3O4@GOQDs-N-(β-alanine)a
MP (ꢀC)
Yieldb
(%)
Reported
[53,66–70]
Entry
Ar
R
Product
7a
Time (min)
TONc
11.4
TOFd (min−1
)
Found
1
2
3
4
5
6
7
8
4-MeOC6H4
4-FC6H4
4-MeC6H4
4-FC6H4
4-ClC6H4
Ph
4-MeC6H4
4-MeC6H4
4-ClC6H4
4-ClC6H4
4-ClC6H4
4-ClC6H4
4-MeOC6H4
4-MeOC6H4
20
15
15
10
20
20
10
15
95
90
88
92
96
95
92
88
0.57
0.72
0.7
247–250
241–244
257–259
242–245
249–252
215–218
207–210
257–259
247–249
241–243
258–260
243–245
248–250
216–219
209–211
252–256
7b
10.8
7c
10.56
11.04
11.52
11.4
7d
1.1
7e
0.57
0.57
1.1
7f
Ph
7g
11.04
10.56
2,3-Cl2C6H3
7h
0.7
aConditions: aldehyde (1 mmol), isatoic anhydride (1 mmol), Amin (1.1 mmol), H2O (5 mL), catalyst (10 mg), room temperature.
bIsolated yields.
cTurnover number.
dTurnover frequency.
GOQD, graphene oxide quantum dot; MP, melting point.

16 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR

KHALEGHI ABBASABADI ≻AND AZARIFAR
17 of 20
SCHEME 7 A possible mechanism for the synthesis of
2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile derivatives 4a-i catalyzed by
Fe3O4@GOQDs-N-(β‐alanine)
SCHEME 8 A possible mechanism for the
synthesis of 2,3-dihydroquinazolin-4(1H)-ones
derivatives 7a–h catalyzed by
Fe3O4@GOQD-N-(β-alanine)

18 of 20
KHALEGHI ABBASABADI ≻AND AZARIFAR
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5 | CONCLUSIONS
The study reports for the first time the preparation of
a
novel magnetic β-alanine-functionalized GOQDs
(Fe3O4@GOQDs-N-β-alanine). The structure of the
synthesized magnetic nanoparticles was fully character-
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XRD, SEM, TEM, TGA, EDX, and VSM analyses. The syn-
thesized Fe3O4@GOQDs-N-β-alanine nanosheets as an
efficient and reusable basic heterogeneous nanocatalyst
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smoothly in H2O as green solvent to afford the products in
excellent yields. The attractive features of this protocol are
high yields of the products, use of a green solvent, simple
work-up procedure, low reaction times, and easy recycling
and reusability of the catalyst.
ACKNOWLEDGEMENTS
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CONFLICT OF INTEREST
The authors declare no conflict of interest.
ORCID
Masoud Khaleghi Abbasabadi https://orcid.org/0000-
0002-1670-4542
Davood Azarifar https://orcid.org/0000-0002-7331-2748
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How to cite this article: Khaleghi Abbasabadi M,
Azarifar D. β-Alanine-functionalized magnetic
graphene oxide quantum dots: an efficient and
recyclable heterogeneous basic catalyst for the
synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-
dione and 2,3-dihydroquinazolin-4(1H)-one
derivatives. Appl Organomet Chem. 2020;e5872.
https://doi.org/10.1002/aoc.5872
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