Preyssler Heteropoly Acid Supported on Nano-SiO2 As a Green, Efficient and Reusable Catalyst in Direct Alkylation of Indole with 1,3-Dicarbonyl Compounds

we used nano-SiO2-supported Preyssler heteropolyacid (HPA) as a green and reusable catalyst to improve direct alkylation of indole with 1,3- dicarbonyl under mild reaction condition. This catalyst can be easily seperated along with the good yields of the products.