Natural talc: a basic, cost-effective, and available catalyst for the one-pot synthesis of dihydropyranochromenes and pyranopyrazoles, along with related DFT calculations

Abstract

Abstract This study investigates environmentally friendly and efficient protocols for synthesizing two distinct heterocyclic scaffolds: pyranopyrazoles and dihydropyranochromenes. Dihydropyranochromenes were synthesized using talc in refluxing ethanol, while pyranopyrazoles were obtained from solvent-free under mixing conditions. The advantages of these methods include high yields, operability, and the use of an accessible, inexpensive, and non-toxic basic catalyst. The reaction conditions, including reaction time, molar ratios of reactants, and catalyst amount, were optimized for the synthesis of products, resulting in high yields of 97% for pyranopyrazoles and 95% for dihydropyranochromenes. The synthesized products were characterized using analytical techniques, including FTIR and NMR, which confirmed the successful synthesis. In this study, total energy and band gap energy calculations were performed for dihydropyranochromenes and pyranopyrazoles derivatives. This suggests that talc powder a natural catalyst, can enhance organic synthesis and offer a sustainable and environmentally friendly solution for modern organic chemistry.