On water synthesis of pyran–chromenes via a multicomponent reactions catalyzed by fluorescent t-ZrO2 nanoparticles. Issue 123 (25th November 2015) - Saha, Arijit
Abstract : Here, we have reported multicomponent synthesis of diverse pyran fused chromenes namely 2-aminochromene, dihydropyrano[3, 2- c ]chromene, and chromeno[4, 3- b ]chromene derivatives using fluorescent t -ZrO2 nanoparticles as reusable catalyst in water. Abstract : Here, we have demonstrated fluorescent tetragonal ZrO2 nanoparticle ( t -ZrO2 NP) catalyzed green one-pot multicomponent protocol for the synthesis of diverse pyran-fused chromene analogues such as 2-aminochromene, dihydropyrano[3, 2- c ]chromene, and chromeno[4, 3- b ]chromene derivatives in water. The rate of the reactions and yields of the products increased significantly in water. In addition, t -ZrO2 NPs showed a higher reactivity than monoclinic ZrO2 NPs. The t -ZrO2 NPs were recycled and the gradual decrease in yield of the product using recycled catalyst could possibly be due to the decrease in Zr-content associated with a decrease in the oxygen vacancies which was evident from fluorescence and atomic absorption studies. However, the tetragonal phase of the catalyst remained intact even at the 10 th cycle.