Constructed Containing Sulfur Heterocyclic Compound From Thioisatin

Sulfur chemistry plays an unusual role in exploring the origin of life.Although the content of sulfur is not rich in nature,it plays a very important role in life activities.Therefore,S,C,H,O,N and P constitute the six most important elements in the human body.Sulfur has been widely used as the simplest chemical material long ago.With the deepening of scientific research.Chemists have discovered that sulfur-containing heterocycles are widely present in many natural products,drug molecules and functional organic materials,and they play a very important role in life.Therefore,the development and synthesis of sulfur-containing heterocycles has attached widespread attention of scientific researchers.In this thesis,we will mainly use thioisatin as the organic sulfur source to synthesize a series of sulfur-containing heterocycles.1)Through a three-component reaction,acetylhydrazine is used to promote the cleavage of the C-S bond of thioisatin to get a sulfide anion intermediate.The sulfide anion intermediate undergoes a nucleophilic substitution reaction with bromoacetophenone and undergoes two cyclizations to obtain benzothienopyridazinone compounds.In this reaction,the substrate scopes are wide and reaction yields are high.The workup is simple2)For amines to promote thioisatin ring opening,after amine catalyzed C-S bond cleavage of thioistin,the nucleophilic substitution with ethyl 4-chloroacetoacetate or Nazarov reagent taken place.Then,the benzothiophenopyrrolidone or chromenopyrrolidone can be obtained by further cyclizations.These reactions can be carried out in environmentally friendly solvent（water or ethanol）.The reaction mechanism has been studied by DFT calculations.3)With our research on ethyl 4-bromo-3-oxobutanoate,we found that it can undergo[4+3]cyclization with conjugated imines,obtaining a series of nitrogen-containing seven-membered heterocyclic compounds.By adjusting the difference of heteroatoms in conjugated imines,benzofuran or benzothieno fused aza-seven-membered ring products can also be obtained.In this paper,124 new compounds were synthesized.All the new compounds were characterized by ¹H NMR,¹³C NMR,IR,HRMS and mp（solid）and representative compounds was determined by X-ray single crystal diffraction analysis...