Computational And Experimental Study On The Mechanism Of A Novel Tandem Reaction

As computers become more powerful and accessible, and as chemists develop better algorithms and software, a larger variety of problems in chemistry can be tackled by computational methods. Not so long ago, computational chemistry was almost synonymous with quantum chemistry, but this is not longer true. Today, computational methods are used as a powerful tool in all the branches of chemistry. It has brought chemistry into a new age- theoretical chemistry and experimental chemistry combine together to uncover the properties of molecular system. One of the most important branches of computational chemistry is to study the mechanism of chemical reactions, especially the mechanism of organic reactions. Not only can it give a precise and detailed reaction pathway, structural information, energies, kinetics and dynamics parameters, and also it can compare the results to experiment to explain the experimental results, or to predict properties of unknown chemical species. Although a lot of achievements have been made, most studies are focused on the small molecular system and simple reactions. Few reports have been given for the complicated or multi-step reactions.Based on the combination of the computational chemistry and experimental chemistry, the mechanism of a novel tandem reaction by which substituted imidazo[1,5-a]pyridine derivatives were formed has been investigated. This tandem reaction was discovered by us while we brought into effect in a project that related to develop new antihypertension drug. By this reaction, poly-substituted imidazo[1,5-a]pyridine derivatives, which significantly important in pharmaceutical and biological fields, can be easily synthesized by the reactionof 2,4-disubstitutedimidazole-5-carboaldehyde with ethyl γ-bromocrotonate derivatives inpresence of base as catalyst . It is considered as a sample for construction of the complicated heterobicyclic compounds with tandem reaction..The goal of this study is to explore the details of the reaction mechanism, To solve the problems met in the experiments, to understand this tandem reaction more accurately and...