Nanopeanut shellOSO3H: Green and naturalbased renewable nanocatalyst for onepot synthesis of dihydropyrano[3,2b]chromenedione derivatives

Nanopeanut shell‑OSO lt;sub gt;3 lt;/sub gt;H nanoparticles were simply prepared and characterized by the scanning electron microscopy (SEM), transmission electron microscope (TEM), fourier transform infrared (FTIR), energy dispersive Xray spectroscopy (EDX), and thermal analysis techniques (TGA/DTG). The catalytic activity of nanopeanut shell‑OSO lt;sub gt;3 lt;/sub gt;H was studied in the synthesis of biologically important 4 lt;em gt;H lt;/em gt;pyran derivatives. The reaction involves the use of Kojic acid, 5,5dimethyl1,3cyclohexanedione, and various benzaldehydes. A wide range of benzaldehydes is compatible in this reaction, producing excellent yields in a short time. The successful synthesis of dihydropyrano[3,2 lt;em gt;b lt;/em gt;]chromenedione derivatives shows that nanopeanut shell‑OSO lt;sub gt;3 lt;/sub gt;H has high catalytic activity and can be effectively used as a green catalyst.