Imidazole Functionalized Magnetic Fe3O4 Nanoparticles: An efficient, green and recyclable catalyst for theone-pot Friedländerquinoline synthesis

SobhanRezayati1,MogharabTorabiJafroudi2,EshaghRezaeeNezhad1, RahimehHajinasiri3, and Sima Abbaspour2

1 Department of Chemistry, PayameNoor University, Tehran, P.O. Box 19395-4697, Iran

2 Department of Chemistry, Faculty of science, Islamic Azad University, Rasht Branch, Rasht, Iran

3 Chemistry Department, Qaemshahr Branch, Islamic Azad University, PO BOX 163, Qaemshahr, Iran

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Table of contents

Materials and methods / 2
Preparation of Fe3O4-IL-HSO4 / 2
General procedure for the one-pot synthesis of quinolinesderivative3a-n / 3
FT-IR spectra of (A) MNP, (B) IL, (C) MNPs–IL / 4
XRD pattern of (A) MNPs, (B) MNPs–IL / 5
SEM images of (A) Fe3O4nanoparticles, (B) MNPs–IL / 6
TEM images of (A) MNPs, (B) MNPs–IL / 7
Magnetization curves of (A)MNPs and (B)MNPs–IL / 8

Materials and methods

FeCl2.4H2O (99%), FeCl3.6H2O (98%), 2-Aminoaryl ketones, 1,3-diketones or ketones, and other chemical materialswere purchased from Fluka and Merck and were used without further purification.All compounds are known and their structures were identified by comparing their melting points and 1H and 13C-NMR data with those reported in the literature.1H-NMR and 13C-NMR spectra were obtained in CDCl3 at 500 MHz and 125 MHz respectively. Chemical shifts are given in ppm with respect to internal TMS, and J values are quoted in Hz.IR spectra of the compounds were obtained on a Perkin Elmer spectrometer version 10.03.06 using a KBr disk.Melting Points were taken on an Electrothermal capillary melting point apparatus and are uncorrected.The phasespresent in the magnetic materials were analyzed using apowder XRD, Philips (Holland), model X0Pert with X´ Pert withCuKα1 radiation (λ = 1.5401 Å), and the X-ray generatorwas operated at 40 kV and 30 mA. Diffraction patternswere collected from 2h = 20º–80º. The purity of the substrate and reaction monitors were accompanied with TLC on Silica-gel polygram SILG/UV 254 plates.

Preparation of Fe3O4-IL-HSO4

The magnetite nanoparticles were prepared by theconventional co-precipitation method [55]. 1-methyl-3-(3-trimethoxysilylpropyl)imidazolium chloride (IL), was prepared from thereaction of imidazole with (3-chloropropyl)trimethoxysilane was heated at 120 °C for8 h with continuous stirring under N2 atmosphere [56].Then an excess amount of KHSO4 were added intodeionized water and stirred for 24 h at roomtemperature. KCl, which was prepared during theexchange of chloride anions with HSO4 [57] and MNP-IL-HSO4 was separated by magnetic decantation,washedwith acetonitrile and dichloromethane, and left to dry ina desiccator.

General procedure for the one-pot synthesis of quinolines derivative 3a-n

A mixture of 2-aminoarylketone (2 mmol), 1,3-diketones or ketones (2 mmol) and Fe3O4-IL-HSO4 (15 mg) was stirred at 90 ͦC for thespecified time (see Table 3). The reaction was monitored by TLC. After completion of the reaction, as monitored by TLC, the reaction mixture was cooled to room temperature, and extracted by EtOAc (10 mL) to separate the catalyst (the productis soluble inEtOAc).EtOAc was removed, and the crude product was recrystallized fromaqueous ethanol (90%) to afford the pure racemic product whichrequired no further purification.The recovered catalyst was washedwith EtOAc (2 × 10mL), dried and reused for the next run. The catalystwas reused for four times without any significant changes in the yieldand the reaction time.All the products were identified with Melting point, 1H-NMR and 13CNMR spectroscopy techniques.

Fig. 1.FT-IR spectra of (A) MNP, (B) IL, (C) MNPs–IL

Fig. 2.XRD pattern of (A) MNPs, (B) MNPs–IL

(A)

)B)

Fig. 3.SEM images of (A) Fe3O4nanoparticles, (B) MNPs–IL

Fig. 4.TEM images of (A) MNPs, (B) MNPs–IL

Fig. 5.Magnetization curves of (A)MNPs and (B)MNPs–IL

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