Regio-and stereoselective cycloadditions and further transformations of azomethine imine derivatives of fused [1,2,4]triazines

摘要

1,3-Dipolar cycloadditions of azomethine imine derivatives of dihydro[l,2,4]triazolo[3,4-c]benzo[l,2,4]triazines with asymmetric dienophiles proceeded in regio- and stereoselective manner.Cycloadditions with fumaronitrile resulted in a mixture of epimeric products,which under more forced conditions underwent ring opening reaction.Comparison of results obtained with cycloadditions with fumaric and maleic acid derivatives provided experimental support for the suggested epimerization.The dipolar cycloadditions were extended for isocyanates and isothiocyanates to yield new fused triazolinones and triazoline thiones.