Study On The Like-Biginelli And Hantzsch Reactions Under Microwave Irradiation And Solvent-free Conditions

Heterocyclic compounds is important for a class of organic compounds.Since 1857 pyrrole was isolated from bone tar by Anderson. It is only more than a century that Meyer dramatically found thiophene in 1882. However, heterocyclic compounds which are researched have been developed to the alarming figures.The number of heterocyclic compounds in the 1930s recorded by Beilstein organic chemical manual is about one third of hundreds of thousands of known organic compounds. More than half of known millions of organic compounds is heterocyclic compound. The proportion of heterocyclic compound in organic compounds is increasing. With the mushrooming of the number of heterocylic compound, its sorts become more and more complex. The scope of application of heterocyclic compound continuously expands.Rarely consider the application of heterocyclic compounds in the method of classical organic systhesis. Because heterocyclic compound is systhesized by chain compound, then the latter is systhesized by the former, thus the steps are added. But actually many heterocyclic compounds are easy to be synsthesized and manipulation is simple, yield is high. Some compounds are difficult to be synsthesized, but heterocyclic compounds are easy. For example, heterocyclic compounds gain in the carbon chain. , heterocyclic compounds are a class of pharmacologic active small molecule heterocyclic compounds, many researchers refer to small molecule compounds and their ramification as matrix to filter antibacterial madication, So studying of the synthesis of heterocyclic compounds is very important.This dissertation integrate our lab research work foundation and feature, carrying on new reseach task, We investigated condensation by focused microwave radiation method without solvent and catalysis emphasizedlly to product a series of organic heterocyclic compounds.This dissertation is classified into three chapters:Chapter 1 Literature SurveyIn this chapter we review the development and application in the area of microwave irradiation and solvent-free synthesis in recent years in detail. Chapter 2 Synthesis of 3, 4 - dihydropyrimidine -2 - thione Derivatives under microwave irradiation and solvent-free conditionThis chapter reported the synthesis of thirty two Dihydropyrimidine thione derivatives with good yields. They have been synthesized by the Biginelli condensation reaction of aromatic aldehyde, acetoacetic ester and thiourea catalyzed by microwave-assisted without any solvent or catalyst. With this method not only the reaction condition is tender, the reaction time is shorter, but also it avoid using catalyst. And the disposal process is simple, avoid the use of solvent which can pollute the environment, this method accord with the green synthesize request.Chapter 3 Study on the Like Hantzsch Reactions under Microwave Irradition and Solvent-free ConditionsThis chapter reported the synthesis of twenty polyhydroquinolines derivatives. They have been synthesized by the Hantzsch condensation reaction of various aromatic aldehydes or heterocyclic aldehydes with dimedone, acetoacetic ester and ammonium acetate under focused microwave-assisted and solvent-free conditions has been expanded to form a series of polyhydroquinolines in good to excellent yields. All products were characterized by IR, NMR, and elements analysis. With this method not only the reaction condition is tender, the reaction time is shorter, but also it avoid using the expensive catalyst. And the disposal process is simple, avoid the use of solvent which can pollute the environment,The methodology is in accordance with the requirement of green chemistry.