Fe3O4 magnetic nanoparticles coated with a copolymer: a novel reusable catalyst for one-pot three-component synthesis of 2-amino-4H-chromene

Isoniazid-functionalized Fe3O4 Magnetic Nanoparticles as a Green and Efficient Catalyst for the Synthesis of 3, 4-dihydropyrimidin-2(1H)-ones and their Sulfur Derivatives

BACKGROUND

A wide variety of dihydropyrimidins (DHPMs) exhibit pharmacological and biological activities. Herein, an efficient one-pot synthesis of some 3, 4-dihydropyrimidin-2(1H)-one derivatives is reported using Fe3O4 @SiO2-Pr-INH.

OBJECTIVE

Recently, several catalysts have been used to improve the Biginellis-reaction. However, some of these catalysts have imperfections. Herein, a convenient method for the synthesis of 3, 4-dihydropyrimidin- 2(1H)-ones and their sulfur derivatives using Fe3O4 @SiO2-Pr-INH is reported.

MATERIALS AND METHODS

Firstly, the catalyst was synthesized through a simple four-step method. The Fe3O4 MNPs were synthesized using the chemical co-precipitation method, coated with a layer of silica using TEOS, and then functionalized with CPTMS. Subsequently, a nucleophilic substitution of Cl by isoniazid resulted in the formation of the magnetic Fe3O4@SiO2-Pr-INH. After the preparation and characterization of Fe3O4@SiO2-Pr-INH, its catalytic activity was studied in the synthesis of 3, 4-dihydropyrimidin-2(1H)-one derivatives. Following the optimization of the reaction conditions, several 3, 4-dihydropyrimidin-2(1H)-one derivatives were synthesized by the reaction of ethyl acetoacetate or acetylacetone, thiourea or urea and aromatic aldehydes at 80 °C under solvent-free conditions.

RESULTS

Isoniazid-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@SiO2-Pr-INH) were prepared using Fe3O4 with silica layer and their surface was modified with isoniazid. They were characterized successfully by infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and were used for the synthesis of some 3, 4-dihydropyrimidin-2(1H)-one derivatives as catalysts. Aromatic aldehydes with electron-donating or electron-withdrawing groups afforded 3, 4- dihydropyrimidin-2(1H)-ones and their sulfur derivatives in good to excellent yields in short reaction times.

CONCLUSION

Isoniazid-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@SiO2-Pr-INH) were used as an efficient catalyst for Biginelli-type synthesis of 3, 4-dihydropyrimidin-2(1H)-ones and 3, 4-dihydropyrimidin- 2(1H)-thiones in good to excellent yields and short reaction times. It is noteworthy that this method has several advantages such as simple experimental procedures, the absence of solvent, environmentally benign process, stability and reusability of the catalyst.

An Efficient Synthesis of Benzimidazole and Benzothiazole Derivatives Using a Nickel(II) Metal-Organic Framework

BACKGROUND

The benzimidazoles and benzothiazoles have shown relatively high pharmaceutical and biological activities. In recent years, numerous methods have been developed for synthesis of benzimidazole and benzothiazole derivatives using different catalysts. However, only some of the reported procedures are quite satisfactory and most of them have drawbacks. Herein, we report a convenient method for synthesis of benzimidazole and benzothiazole derivatives using a nickel (II) metal-organic framework (Ni- MOF) as a novel and reusable catalyst. The presence of unsaturated metal centers makes metal-organic frameworks to be used as Lewis acid catalysts.

OBJECTIVE

The primary objective of this study was to describe an efficient method for synthesis of benzimidazole and benzothiazole derivatives.

METHOD

Ni-MOF was prepared using the modified evaporation method and was characterized by FE-SEM, FT-IR, TGA, and XRD techniques.The catalyst was then used to test the synthesis of some benzimidazole and benzothiazole derivatives. The benzimidazoles and benzothiazoles were characterized by Elemental analyses, HNMR and IR techniques.

RESULT

A variety of aromatic aldehydes bearing electron donating groups or electron-withdrawing were reacted with 1,2-phenylenediamine or 2-aminothiophenol using Ni-MOF in good to excellent yields.

CONCLUSION

In summary, a new and highly efficient method was developed and reported for the synthesis of benzimidazole and benzothiazole derivatives using nickel(II) metal-organic framework. The advantages are short reaction times, good to excellent yields, the environmentally benign and simple procedure, stability, nontoxicity, recyclability, and easy separation of the catalyst.