Nanostructured coumarin-based cobalt complex as an efficient, heterogeneous and recyclable catalyst for the three-component synthesis of benzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives

High-performance Fe3O4@SiO2@M-D and Fe3O4@SiO2@M-D-Cu with amine branches and decorated with copper metal for one-pot synthesis of chromene and xanthene derivatives

In this project, we introduced new heterogeneous nanocatalysts featuring amine branches and decorated with inexpensive copper metal (Fe3O4@SiO2@M-D-Cu and Fe3O4@SiO2@M-D). These nanocatalysts were characterized using several analytical techniques, including SEM, FT-IR, EDX, XRD, TGA, and ICP-OES. We investigated their catalytic activity in traditional pot reactions, focusing on the three-component synthesis of xanthene and chromene compounds. The properties and future potential of these nanocatalysts include high yield, recyclability, ease of operation, and the use of environmentally friendly solvents. Additionally, the catalysts can be easily removed from the reaction solution using an external magnet and reused up to eight times without a decrease in catalytic activity.

L-Aspartic acid-functionalized magnetic nanoparticles: as a new magnetically reusable bifunctional acid-base catalysts for the synthesis of benzo[b]pyran and pyrano[3,2-c] chromene derivatives

"Green chemistry" describes the development of new technologies that reduce or eliminate the need for hazardous compounds or the production of them. In order to accomplish this goal, we have developed a new magnetic recyclable biocatalyst in this study by successfully applying aspartic acid to magnetic nanoparticles. Aspartic acid's molecular makeup made it possible for it to stabilize on magnetic nanoparticles using a straightforward method. We characterized the synthesized catalyst using microscopic and spectroscopic techniques such as Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). The catalytic activity of this organocatalyst was evaluated for the synthesis of benzo[b]pyran and pyrano[3,2-c] chromene derivatives, exhibiting excellent efficiency. This protocol offers several benefits, such as using a low-cost biocatalyst, nontoxicity, high product yield, easy separation, short reaction times, catalyst reusability, and H2O/EtOH solvent. In summary, our research indicates a feasible approach towards developing a novel magnetic biocatalyst suitable for application in organic synthesis.

One-pot synthesis of chromenes in the presence of nano-cellulose/Ti(IV)/Fe3O4 as natural-based magnetic nano-catalysts under solvent free conditions

In this study, the preparation of magnetic catalysts of titanium tetrachloride stabilized on nano-cellulose named cellulose/Ti^(IV)/Fe₃O₄ was investigated. Various methods such as XRD, SEM, FT-IR, BET, EDX, TEM, TGA and VSM were used to characterize the catalysts. Then, the identified catalysts were used for the synthesis of various chromene skeletons via reaction of malononitrile, aldehyde and dimedone, 4-hydroxycoumarine or 2-naphthole at 70 °C under solvent free conditions. The spectroscopic methods used to determine the structure of the products include ¹³C NMR, ¹H NMR and FT-IR.

In this study, the preparation of magnetic catalysts of titanium tetrachloride stabilized on nano-cellulose named cellulose/Ti^(IV)/Fe₃O₄ was investigated.