The Research On The Aldehydes With Nitromethane To Form Isoxazoles And 1,3-dinitroalkanes

As an ordinary organic raw material,the chemical reactions of aldehydes have attracted much attention by researchers.The reaction of aldehydes with nitromethane has also been spreading up to now as a classical name reaction-Henry reaction.The reaction has been deeply studied,and some research results have been obtained.However,as an important pharmaceutical active substance,isoxazoles have not been synthesized from nitromethane and aldehydes.Among the reported methods about synthesizing 1,3-dinitrocompounds,there are some disadvantages of not readily available catalysts,harsh reaction system and poor structure range.Therefore,it is of great significance to develop novel methods to synthesize isoxazoles and1,3-dinitrocompounds from nitromethane and aldehydes.In this paper,we studied the synthesis of isoxazoles and 1,3-dinitrocompounds catalyzed by copper acetate.The main researches are as follows:（1）The synthesises of isoxazoles and 1,3-dinitrocompounds are summarized.We expounded the purpose,significance and primary contents of this research.（2）A systematic study for synthesises of isoxazoles from nitromethane and aldehydes was made.The factors influencing the reactions were screened.And the best reaction conditions were:aldehydes（0.5 mmol）,nitromethane（10.0 mmol）,hydrate copper acetate（20 mol%）,NH₄I（0.5 mmol）,iso-propanol（2 mL）,60 ^oC,stirred 28 h under air.With the optimized conditions,we investigated the applicabilities of benzaldehydes and other aldehydes.We have test ed some aldehydes in gram scale.Furthermore,the transformation of a functional group for some isoxazoles was conducted.Finally,we studied the reaction mechanism,and proposed a possible reaction mechanism.（3）A systematic study for synthesises of 1,3-dinitrocompounds from nitromethane and aldehydes was made.The factors influencing the reactions were screened.And the best reaction conditions were:aldehydes（0.5 mmol）,nitromethane（10.0 mmol）,hydrate copper acetate（20 mol%）,NH₄I（0.4 mmol）,water（2 mL）,100^oC,stirred 24 h under air.With the optimized conditions,we investigated the applicabilities of aromatic aldehydes and non-aromatic aldehydes.The results showed that this protocol is compatible with both aromatic and non-aromatic aldehydes.