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.