Studies On The Synthesis Of Spiro Pyrazoline Based On The Cycloaddition Reaction Of Nitrile Imines

In recent decades,medicinal chemists have gradually discovered that a larger number of bioactive molecules isolated from natural products possess spiro heterocyclic structures.Structurally,such spiro compounds feature the following characteristics: Firstly,they have helical conjugation and helical super-conjugation due to their special three-dimensional electronic effects;Secondly,the introduction of helical heterocyclic structures in the molecule can effectively enhance the stability,medicinal properties and biological activity of the compounds.Due to these properties,the synthesis and application of these compounds have become one of the research hot-topics and frontiers in drug synthesis and discovery.As an important class of spiro heterocyclic compounds,pyrazoline derivatives have a wide range of biological activities.In this thesis,a series of spirocyclic compounds with pyrazoline structure were constructed through [3+2] cycloaddition reaction.The thesis consists of the following three chapters:Chapter 1: The Synthesis of aurone compounds and its research progress in cycloaddition reactions.In this chapter,we reviewed the synthetic methods on aurones and its research progress in cycloaddition reactions.Chapter 2: Studies on the [3+2] cycloaddition reaction of benzoaurone and nitrile imine.In this chapter,we studied on the regioselective [3+2] cycloaddition reaction of benzoaurone with nitrile imine.Resorting on this effective strategy,a series of appealing spiro-naphthofuranone-pyrazolines were constructed with high regioselectivity.This new type of framework further enriched the types of spiro compounds.In addition,the synthesis method has the advantages of simple operation,mild reaction conditions,no catalyst,good functional group tolerance,and scale-up scale.Chapter 3: Studies on the [3+2] cycloaddition reaction between benzylidene pyrazolinone and nitrile imine.In this chapter,we mainly studied on the [3+2] cycloaddition reaction of benzylidene pyrazolinone and nitrile imine,and we have successfully constructed spiro-pyrazoline-pyrazolinone compounds in higher yields via this [3+2] cycloaddition.Thise reaction highlights the mild conditions,the simple operation and the broad substrate scope.