Nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. The catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. The size of nanoparticles were observed with SEM.All prepared compounds with melting points, 1H NMR and 13C NMR were characterized. High yields, simple operation, easy-work procedure, mild reaction conditions are some advantages of this protocol. The present method does not involve any hazardous organic solvent. Therefore, this procedure could be classified as green chemistry. پرونده مقاله

Nano-peanut shell‑OSO3H nanoparticles were simply prepared and characterized by the scanning electron microscopy (SEM), transmission electron microscope (TEM), fourier transform infrared (FT-IR), energy dispersive X-ray spectroscopy (EDX), and thermal analysis techniques (TGA/DTG). The catalytic activity of nano-peanut shell‑OSO3H was studied in the synthesis of biologically important 4H-pyran derivatives. The reaction involves the use of Kojic acid, 5,5-dimethyl-1,3-cyclohexanedione, 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-b]chromenedione derivatives shows that nano-peanut shell‑OSO3H has high catalytic activity and can be effectively used as a green catalyst. پرونده مقاله