Porous nanorods as catalyst for one-pot synthesis and oxidation of tricyclicdihydropyrimidine derivatives in aqueous medium

At the beginning of the new century, it is widely accredited that the development of efficient, practical and environmentally friendly methods of synthesis has been recognized as one of the most important topics of modern organic synthesis [1]. As the biggest pollution problem in many synthetic organic processes is with organic solvents,the development of efficient synthetic methodologies for organic reactions in the presence of non-toxic solvents is an important challenge. It is known that water is a nonflammable, non-hazardous, non-toxic, uniquely redox-stable and inexpensive green solvent. Therefore, using water as the reaction medium has gained considerable interest [2]. In recent years, much attention has been devoted towards dihydropyrimidine (DHPM) derivatives as the most important classes of tricyclic compounds, due to their significant therapeutic and biological activities, such as antiviral, antibacterial, anti-inflammatory, anti-hypertensive, anti-tubercular, anti-malarial, cytotoxic, and DNA-topoisomerase activities [3-6]. Thus, it is necessary to further develop an efficient and convenient method to construct this type of heterocyclic compounds. Based on our ongoing efforts in exploring environmentally benign syntheses, herein we report an efficient and green procedure for the synthesis of dihydropyrimidine derivatives in presence of [Porous manganese oxide nanorods (PMN) in water.Facile synthesis of DHPM was achieved by using Porous manganese oxide nanorods under very mild conditions. The product was then oxidized to the desired compound. Further manipulation of this reaction is currently under way in our laboratory.