Glycoluril Dimer Isomerization under Aqueous Acidic Conditions Related to Cucurbituril Formation

Abstract

A water-soluble methylene-bridged glycoluril dimer <b>2S</b> was isolated. It was shown that <b>2S</b> is the only kinetic product of the reaction between glycoluril derivative <b>1</b> and paraformaldehyde. Compound <b>2S</b> is subsequently intermolecularly transformed into its diastereomer <b>2C</b>. The kinetics and thermodynamics of the S- to C-shaped dimer isomerization were investigated under reaction conditions similar to those for cucurbituril synthesis