Utilization of 2-Amino-4-aryl-6-arylnicotinamides in the Synthesis of Some Novel Heterocycles under Microwave Irradiation
|School||Northwest Normal University|
|Keywords||Diaryl Microwave Assisted Pyridine Heterocyclic synthesis Pyrimidine Formylamino Aminothiophene Heterocyclic Compounds Solvent-free conditions bromophenyl Organic Synthesis The reaction can be Reaction selectivity Sulfhydryl Condensation reaction Ketones calcd The methylation reaction NMR Microwave radiation|
During the last two decades years, microwave irradiation as an efficient thermal energy source has become a standard technique in various fields of chemistry, especially in the application in organic chemistry. Synthesis of chemical compounds which normally require long reflux time can be achieved conveniently and very rapidly in a microwave oven. Microwave irradiation can even accomplish some reactions which under the traditional heating conditions do not occur. Compared to the classical heating methods, microwave irradiation has the advantages of short reaction time, highyields, pure products and easy workup. The use of microwave energy to activate organic reactions has been taking a new dimension very recently.Heterocyclic compound is an important 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. 2-Amino-4-aryl-6-arylnicotinamides are a kind of versatile intermediates in organic synthesis. It can be widely used in forming aromatic and heterocyclic compounds. Pyrido[2,3-d]pyrimidines are heterocyclic compounds along with bio-and pharmacologic activities. The scientific and practical demands for such compounds are increasing. Therefore, the combination of 2-amino-4-aryl-6-arylnicotinamides and the synthesis of pyrido[2,3-d]pyrimidines deserve investigation.This dissertation integrate our lab research work foundation and feature, we investigated condensation by focused microwave radiation method to product a series of pyrido[2,3-d]pyrimidines and their heterocyclic derivatives.This dissertation is classified into four chapters:Chapter 1 Literature Survey. In this chapter we review the development and application in the area of microwave irradiation synthesis in recent years in detail.Chapter 2 Focused microwave-assisted efficient and convenient synthesis and methylation of new 5-aryl-2-mercapto-7-arylpyrido[2,3-d]pyrimidin-4-(3H)-ones. This chapter reported under focused microwave irradiation, we first reported a rapid and efficient preparation of new 5-aryl-2-mercapto-7-arylpyrido[2,3-d]pyrimidin-4-(3H)-ones by the condensation of 2-amino-4-aryl-6-arylnicotinamides with methanedithione. Then, the methylation of 5-aryl-2-mercapto-7-arylpyrido[2,3-d]pyrimidin-4-(3H)-ones was affected using dimethyl carbonate(DMC) in the presence of base MgO and catalytic TBAB and DMSO, to rapidly synthesize of 2-(methylthio)-5-aryl-7-arylpyrido[2,3-d]pyrimidin-4(3H)-ones and 3-methyl-2-(methylthio)-5-aryl-7-arylpyrido[2,3-d]pyrimidin-4(3H)-ones. This protocol avoids the use of strong bases and highly toxic agents such as methyl halides or dimethyl sulfate.Chapter 3 Focused microwave-assisted efficient and convenient synthesis of 5-aryl-7-arylpyrido[2,3-d]pyrimidin-4(3H)-ones. This chapter reported a rapid and efficient preparation of 5-aryl-2-phenyl-7-arylpyrido[2,3-d]pyrimidin-4(3H)-ones and spiro[cycloalkane-1,2’-(1’H)-5-aryl-7-arylpyrido[2,3-d]pyrimidin]-4’(3’H)-ones by the condensation of 2-amino-4-aryl-6-arylnicotinamides with benzaldehyde or cycloalkanones under focused microwave irradiation.Chapter 4 Synthesis of 5-aryl-7-arylpyrido[2,3-d]pyrimidin-4-amines/ols under microwave irradiation and solvent-free conditions. This chapter reported synthesis of 2-benzyl-5-aryl-7-arylpyrido[2,3-d]pyrimidin-4-amines and 2-phenyl-5-aryl-7-arylpyrido[2,3-d]pyrimidin-4-ols under microwave irradiation and solvent-free conditions. And the disposal process is simple, avoid the use of solvent which can pollute the environment, this method accord with the green synthesize request.