A 1,3-DIPOLAR CYCLOADDITION OF AZOMETHINE YLIDES TO IMIDAZO[4,5-e]THIAZOLO[2,3-c][1,2,4]TRIAZINE OXINDOLYLIDENE DERIVATIVES IN THE SYNTHESIS OF NOVEL SPIROOXINDOLE DERIVATIVES

Abstract

The stereochemistry of the 1,3-dipolar cycloaddition reaction of azomethine ylides to oxindolylidene derivatives of imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazine leading to a mixture of diastereomeric derivatives of dispiro[imidazothiazolotriazine-7,3'-pyrrolidine-4',3''-oxindole] was studied. It was shown that the corresponding syn- and anti-stereoisomers can be isolated individually by fractional crystallization from reaction mixtures without the use of chromatographic methods.