Synthesis Of Dihydropyrrolediones By Base-promoted Cyclization Of Bromomaleimide And Structure Confirmation

Dihydropyrrolediones are the basic building blocks of many natural and synthetic products.Also dihydropyrroledione derivatives have attracted remarkable interest in the last few years due to their unique biological activities and pharmacological activities.While complicated preparation step and limited structure greatly narrow the practical application of dihydropyrroledione derivatives.Therefore,exploring green and efficient preparation routes is one of the hotspots of many chemists.The tandem reaction has a significant implication in organic synthesis.On one hand,it can obtain some products with unique chemical structure with high selectivity and the intermediates formed in the reaction process will continue to carry out in-situ reaction;On the other hand,the reaction steps are greatly reduced and the resource utilization is quietly increased,which is in line with the atomic economy priciple.Based on the above advantages of tandem reaction and the wide application prospect of dihydropyrroledione derivatives,we carried out the following explorations.Firstly,using maleic anhydride as the raw materials,bromomaleimides were prepared through amidation and cyclization reaction.Then two series of highly substituted dihydropyrrolediones were prepared via a facile approach between the reaction of bromomaleimides and nucleophiles with active methylene groups under a tandem Michael addition and intramolecular cyclization?C-alkylation and O-alkylation respectively?.Finally,the structure confirmation was determined by nuclear magnetic resonance(¹H,¹³C,2D NMR)and high resolution mass spectrometry.This study showed a simple and efficient one-pot procedure to obtain highly substituted heterocyclic compounds and the main contents of this thesis were as follows:1.Using maleic anhydride as the raw materials,a series of bromomaleimides were prepared through amidation,cyclization and electrophilic addition-elimination reactions in good yield.2.A series of novel furo[2,3-c]pyrrole-4,6-dione derivatives were prepared via Et₃N-promoted cyclization of bromomaleimides and 1,3-dicarbonyl compounds with active methylene groups using THF?tetrahydrofuran?as the solvent at room temperature.3.A series of novel azabicyclo[3.1.0]hexane-2,4-dione derivatives were prepared via Et₃N-promoted cyclization of bromomaleimides and nucleophiles containg cyano functional group using THF as the solvent at room temperature in the presence of PTC?phase transfer catalyst?.