Nano silica sulfuric acid catalyzed synthesis of 2-substituted aryl (indolyl) kojic acid derivatives

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.