Study On Synthesis Of Benzothiopyran And Benzothiophene Compounds Using Inorganic Sulfides

The sulfur-containing benzene fused heterocyclic compounds,such as benzothiopyran and benzothiophene,are a very common type of organic intermediates,and their derivatives are widely found in many materials,pharmaceuticals and bioactive natural products.Benzothiopyran compounds have good antibacterial,anti-oxidation and anti-tumor characteristics.And benzothiophene compounds are the basic building block of many drug molecules.Therefore,the synthesis of these two types of compounds is of great significance and value.Sulfur atoms were introduced in order to construct sulfur heterocycles during the synthesis of these compounds.The sources of these sulfur atoms have two types:organic sulfides and inorganic sulfides.Organic sulfides have the characteristics of complex synthesis process and unstable.Compared with organic sulfides,inorganic sulfides have the advantages of cheap and easy to obtain,more stable.In this paper,based on the laboratory research,the new strategy of synthesizing benzothiopyran and benzothiophenes are developed respectively by using potassium sulfide as sulfur source.Chapter one,induction.From the perspective of transition-metal catalyzed and transition-metal-free catalyzed,the synthesis of benzothiopyran and benzothiophene compounds in recent years has been reviewed.Chapter two,study on the transition-metal-free catalyzed synthesis of dihydrobenzothiopyrane-4-one compounds.Under the influence of DBU,2’-halogen chalcones reacts with potassium sulfide.And a series of dihydrobenzothiopyrane compounds were synthesized green and efficiently through the construction of C-S bond twice.The reaction conditions are mild and green.Chapter three,study on the transition-metal-free catalyzed synthesis of 2-carbonyl benzothiophene compounds.On the transition-metal-free catalyzsis,2-halogen chalcone reacts with potassium sulfide And a series of 2-carbonyl benzothiophene compounds were synthesized efficiently.Mechanism study shows this reaction undergoing these four processes of nucleophilic substitution,intramolecular cyclization,protonation and dehydroaromatization.Chapter four,study on the transition-metal-free catalyzed synthesis of Benzothiopyran and benzopyran compounds.Using 2,2’-dihalo chalcone as substrate and potassium sulfide as sulfur source,and they occur the tandem reaction in DMF.Benzothiopyranone and benzothiopyranone compounds were synthesized via many times of C-S/C-O bond formation.