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Supramolecular palladium(II) supported on the modified chitosan by DL-methionine using ethylenediaminetetraacetic acid linker (Pd@MET-EDTA-CS), was designed and prepared through a simple procedure. The structure of this novel supramolecular nanocomposite was...

In this research, a novel supramolecular Pd(II) catalyst supported on chitosan grafted by L-asparagine and an EDTA linker, named Pd@ASP-EDTA-CS, was prepared for the first time. The structure of the...

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In this work, D-(–)-α-phenylglycine (APG)-functionalized magnetic nanocatalyst (Fe3O4@SiO2@PTS-APG) was designed and successfully prepared in order to implement the principles of green chemistry for the synthesis of polyhydroquinoline (PHQ) and 1,4-dihydropyridine (1,4-DHP) derivatives under ultrasonic irradiation in EtOH. After preparing of the nanocatalyst, its structure was confirmed by different spectroscopic methods or techniques including Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and thermal gravimetric analysis (TGA). The performance of Fe3O4@SiO2@PTS-APG nanomaterial, as a heterogeneous catalyst for the Hantzsch condensation, was examined under ultrasonic irradiation and various conditions. The yield of products was controlled under various conditions to reach more than 84% in just 10 min, which indicates the high performance of the nanocatalyst along with the synergistic effect of ultrasonic irradiation. The structure of the products was identified by melting point as well as FTIR and 1H NMR spectroscopic methods. The Fe3O4@SiO2@PTS-APG nanocatalyst is easily prepared from commercially available, lower toxic and thermally stable precursors through a cost-effective, highly efficient and environmentally friendly procedure. The advantages of this method include simplicity of the operation, reaction under mild conditions, the use of an environmentally benign irradiation source, obtaining pure products with high efficiency in short reaction times without using a tedious path, which all of them address important green chemistry principles. Finally, a reasonable mechanism is proposed for the preparation of polyhydroquinoline (PHQ) and 1,4-dihydropyridine (1,4-DHP) derivatives in the presence of Fe3O4@SiO2@PTS-APG bifunctional magnetic nanocatalyst.

A novel and recyclable catalytic system was prepared by linking polyethyleneimine (PEI) to tannic acid (TA) using 1,3-dibromopropane, as a cross-linker, to afford (TA-PEI) composite during a convenient and inexpensive procedure. Moreover, to increase the efficacy of the catalyst and to reduce the reaction time, magnetization and sulfonation of the prepared nano-catalyst have been properly performed to afford the final TA/PEI/magnetic/sulfonated (TPMS) supramolecular heterogeneous nonmagnetic composite. The TPMS catalytic system was characterized by various spectrometric and analytical techniques including Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). Furthermore, the heterogeneous TPMS nanocomposite catalytic sytem demonstrated excellent catalytic activity for the one-pot synthesis of 2,3-dihydroquinazole derivatives through a green and sustainable procedure to afford desired products in good to excellent yields. The supramolecular TPMS catalytic system have several advantages including easy separation, nature-friendly, eco-friendly, cost-effective, and reduced reaction time. The reusability of TPMS nanocatalyst was also investigated and the results showed that there is not any significant decrease in the efficiency of the catalyst after five reaction cycles.

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