A facile and efficient synthesis of tetrahydrobenzo[b]pyrans and dihydropyrano[4,3-b]pyrans derivatives using phosphate fertilizers MAP, DAP, and TSP as heterogeneous catalysts

Talc as a natural mineral catalyst for the one pot-three component synthesis of benzo[f]chromene, dihydropyrano[3,2-c]chromene, and tetrahydrobenzo[b]pyran derivatives under different conditions

Talc is a natural mineral catalyst known by the chemical composition of MgSi4O10(OH)2. which in its pure state consists of 31.88% magnesium oxide, 63.37% silicon oxide, and 4.75% water. The abundance of this material, the ease of extraction, and its properties have made talc an important mineral in industries. In this article, this material, which was extracted directly from the mine, after decontamination, was used for the synthesis of benzo[f]chromene, dihydropyrano[3,2-c]chromene, and tetrahydrobenzo[b]pyran derivatives. The results demonstrated that the catalyst exhibited excellent catalytic performance, leading to the production of products with yields of 79-95%. Additionally, the heterogeneity of the reaction was confirmed through a hot filtration test. Notably, this catalyst presents notable benefits, such as its easy recovery and ability to be reused for a minimum of six successive cycles, a simple work-up procedure, and the attainment of high product yields. Structural and morphological analyzes of the talc were done using Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Energy-dispersive X-ray Spectroscopy (EDS-map) and Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM) techniques.

Nanao/organocatalyat SiO2/4-(2-Aminoethyl)-morpholine as a new, reusable, and efficacious catalyst for the synthesis of polyhydroquinolines derivatives and antibacterially active evaluation

In this study, a new nanocomposite comprising 4-(2-Aminoethyl)-morpholine, an organic catalyst, was prepared on the surface of silica. The absence of metal in the catalyst structure contributes to its environmental friendliness. This novel nanocatalyst was used for multi-component reactions (MCRs). Having a nano size for the composite enhances the contact between the raw materials and the catalytic surface, leading to significant advancement in the reaction. The synthesized composite was identified and evaluated using FT-IR, EDX, EDX-Mapping, TGA, XRD, BET, TEM, and FE-SEM analysis. The characteristic analysis confirmed the synthesis of both nano-silica/4-(2-Aminoethyl)-morpholine catalyst and polyhydroquinoline. The composite's catalytic properties for synthesizing some polyhydroquinoline derivatives were investigated, yielding promising and remarkable results with high 95% yields and short reaction times. The antibacterial properties of the synthesized compounds were also examined against four types of pathogenic bacteria. The highest inhibitory effect was attributed to the compound Ethyl-4-(3-hydroxyphenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate exhibited the highest antibacterial properties.

Bentonite/Ti(IV) as a natural based nano-catalyst for synthesis of pyrimido[2,1-b]benzothiazole under grinding condition

A new natural-based catalyst named Bentonite/Ti(IV) was prepared and characterized by FT-IR, FESEM, TEM, TGA, EDS-MAP, XRD, BET, XRF, XPS and ICP- MS. An efficient and simple one-pot three-component synthesis of pyrimido[2,1-b]benzothiazole derivatives was carried out by the reaction of aldehyde, 2-aminobenzothiazole, and ethyl acetoacetate. In this research, Bentonite/Ti(IV) was used for the synthesis of PBT derivatives in 80 °C under solvent-free conditions by electrical mortar-heater. Solvent-free conditions, simplicity of operation, easy work-up and use of an eco-friendly catalyst are some of advantages of this protocol.