A simple, rapid and effective protocol for synthesis of bis(pyrazolyl)methanes using nickel–guanidine complex immobilized on MCM-41

Design and synthesis of PDSPTCF as an influential Brønsted-Lewis acidic catalyst for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazines

Initially, 4,4'-(1,4-phenylene)di(sulfonic)pyridinium tetrachloroferrate (PDSPTCF) as a novel organic-inorganic hybrid salt was synthesized and identified by elemental mapping, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectrometer, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, vibrating-sample magnetometry, and thermal gravimetric (TG) techniques. Then, the catalytic performance of this hybrid salt was assessed for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazine derivatives via one-pot multicomponent domino reaction (MDR) of benzene-1,2-diamine, 2-hydroxynaphthalene-1,4-dione and aldehydes under optimal conditions (70 °C, solvent-free, 5 mol% PDSPTCF) in short reaction times and high yields. Highly efficacy of the PDSPTCF for the production of benzo[a]pyrano[2,3-c]phenazines can be assigned to the synergistic effect of Lewis and Brønsted acids, and having two positions of each acid (i.e., FeCl4- and -SO3H). In addition, this catalyst showed good reproducibility with six cycles of recycling.

Immobilized Ni on TMEDA@βSiO2@αSiO2@Fe3O4: as a novel magnetic nanocatalyst for preparation of pyrido[2,3-d:6,5-d']dipyrimidines

In the current body of research, a very quick and effectual procedure for the synthesis of pyrido[2,3-d:6,5-d']dipyrimidines has been developed. This method is accomplished through the one-pot multi-component reaction of 2-thiobarbituric acid, NH₄OAc and aldehydes utilizing Ni-TMEDA@βSiO₂@αSiO₂@Fe₃O₄ as a novel mesoporous nanomagnetic catalyst at room temperature. This protocol is one of the few reports of the preparation of these derivatives without the use of conventional heating as well as energies such as microwave and ultrasound radiation. The characterization of the prepared catalyst was well accomplished by different techniques such as FT-IR, ICP-OES, SEM, TEM, BET, XRD, VSM, TGA, EDX and Elemental mapping. This organometallic catalyst was reusable for seven times with negligible decrement in its catalytic performance. In addition, all of the products were produced with high TON and TOF values, which demonstrates that our catalyst has a very high level of activity in the preparation of pyrido[2,3-d:6,5-d']dipyrimidines.

A new copper-supported zinc ferrite as a heterogeneous magnetic nanocatalyst for the synthesis of bis(pyrazolyl)methanes and oxidation of sulfides

In this paper, we report the synthesis of ZnFe2O4@SiO2@APTES@DHBS-Cu as a novel magnetic nanocatalyst, in a mild and green environment. The structure of the described magnetic compound was characterized by different physicochemical techniques including XRD, EDS, AAS, SEM, FT-IR, X-ray elemental mapping, TGA, and VSM analyses. The prepared magnetic nanoparticles exhibit excellent catalytic activity in synthesizing bis (pyrazolyl)methanes and oxidation of sulfide derivatives under green conditions. The heterogeneous nature of the catalyst was confirmed via the hot filtration experiment. Further, ZnFe2O4@SiO2@APTES@DHBS-Cu showed high efficiency and reusability that could be reused for at least five consecutive runs.