Khodabakhsh Niknam

An eco-friendly method for the synthesis of hydroxyspiro[indoline-3,90-xanthene]triones as new spiro[indoline-3,90-xanthene]trione derivatives is described. These syntheses were accomplished via pseudo threecomponent condensation reaction of dimedone and isatin derivatives in the presence of silica-bonded n-propyltriethylenetetraminesulfamic acid in refluxing ethanol. Most of the acid catalysts gave spiro[indoline-3,90-xanthene]triones as the final products. In the present method by using different amounts of acid catalyst and controlling the conditions, hydroxyspiro[indoline-3,90-xanthene]triones were obtained as the only product. The advantages of our method are practical simplicity, using reusable heterogeneous catalyst, short reaction times, and good yields of the products. The recycled catalyst could be reused fifth times without appreciable loss in the catalytic activity. Two compounds were found to display in vitro antioxidant and cholinesterase inhibitory activities.