Green Synthesis of Pyrazol‑chromeno[2,3‑d]pyrimidinones Using SBA-Pr-SO3H as an Efficient Nanocatalyst

Abstract

<em>Hexagonal mesoporous silica (SBA-15) was prepared and then </em><em>functionalized by</em><em>(3-mercaptopropyl)trimethoxysilane. The obtained 3-mercaptopropyl functionalized SBA-15 (SBA-Pr-SH)</em><em> was then oxidized using H₂O₂ in methanol under an acidic condition to give </em><em>sulfonic acid functionalized mesoporous silica (SBA-Pr-SO₃H).</em><em> The latter was characterized using different techniques (including TGA, BET, BJH, CHN, SEM, and TEM) and then used as a catalyst in organic synthesis. In the next step, SBA-Pr-SO₃H catalyzed the three-component reaction of pyrazolone, salicylaldehydes, and barbituric acid in water under reflux condition. Through this procedure various pyrazolchromeno[2,3-d]pyrimidinone derivatives were obtained. The reaction conditions were completely green due to the use of water as a solvent and the presence of an environmentally benign catalyst.</em>