EDA-TFA Catalyzed Condensation Of Aldelaydes And Nitroalkanesand The Application In Syntheses Of Isoquinoline Alkaloids

Nitroalkenes is a kind of extremely important compounds.It can be used in Michael addition and cycloaddition.It can also be reduced into amines,and can behydrolyzed into acids.In addition,it can be usedfor efficient syntheses of pesticides,fungicides and some physiologically active substances.In this paper,we studied the EDA-TFA catalyzed condensationof aldehydes and nitroalkenes to prepare nitroalkenes via Henry reaction and dehydration.We have studies the influence of salts of CF3COOH with various amines,salts of ethylenediamine with various acids,solvents,etc.We found that the optimum conditions of the condensation were as follows:ethylenediaminium trifluoroacetate acid(EDA-TFA)was the best catalyst,DMSO was the best solvent,the best temperature was 115±5?,and the best ratio of reactants was 1:2:0.05(aldehyde/nitroalkane/EDA-TFA).A total of twentyfour substituled nitroalkenes could be obtained under the optimum reaction conditions.In addition,the above method was suceessfully used to prepare the key intermediates for synthesis of isoquinoline alkaloids Mansouramycin B and Caulibugulone A.