Study of acid catalyzed synthesis and analytical preparative separation of the spatial isomers of N,N-dimethylglycoluril

Abstract

Alkylglycolurils are promising class of organic compounds characterized by a wide spectrum of psychopharmacological activity such as tranquilizing, neuroleptic, antidepressant and psychostimulating. However, there are conflicting data on the methods of obtaining and identifying isomers of N,N’-dimethylglycoluril in the literature. Our aim is to study the reaction of glyoxal with N-methylurea in acid-catalyzed conditions in various media, develop analytical, preparative separation and identify regioisomers. We developed a method for separating the trans- and cis- isomers of N,N’-dimethylglycoluril by high-performance liquid chromatography. As a result of this analysis, it was possible to separate the cis- and trans- isomers of N,N’-dimethylglycoluril with retention times, namely, for trans it was 6.998 min and for cis- was 9.704 min. We proposed an alternative method based on preliminary thin-layer chromatography control of the reaction mass to expand the preparative possibilities for the separation of regioisomers of dimethylglycoluril, and their subsequent separation by column chromatography. Comparison of the samples of compounds 1a and 1b obtained by preparative highperformance liquid chromatography and column chromatography showed complete identity of their physicochemical. It was also established that the reaction of glyoxal with N-methylurea under strong acid conditions was completed mainly by formation of the trans-isomer, in some cases reaching 90 % of regiospecificity. In addition, the combination of physicochemical studies of the cis- and trans- isomers of has made it possible to reliably and unambiguously characterize these isomers.