Functionalized Nano-Zeolite-NaY with –SO3H and Ca: Fabrication and its Catalytic Performance in the Four-Component Synthesis of Benzimidazolopyrimido Pyrimidines

In this study, solid zeolosulfuric acid (SO3H@zeolite-Y) was first obtained by the reaction of zeolite-NaY with chlorosulfonic acid. Ca2+ ions were then stabilized on the surface of zeolosulfuric acid by metal exchange method (Ca/SO3H@zeolite-Y). The structure and morphology of this new bi-functionalized nanoporous was investigated and identified usingFT-IR, FESEM, EDX and BET instrumental analyses. In the following, its catalytic activity in the synthesis of benzimidazo[2,1-a]pyrimido[5,4-d]pyrimidines through the four-component reaction of 2-amino benzimidazole, cyanoacetamide and two moles of different aromatic aldehydes under green conditions was considered. One of the obvious advantages of this nanocatalyst is the presence of Lewis (Ca2+) and Brunsted acid (-SO3H) sites on a nanoporous solid substrate, which can be very useful and important in multi-component syntheses. Simplicity of the procedure, the ability to recycle the catalyst and easy separation of the product, high yield and mild conditions are other advantages of this method.