A water soluble tetramethyl-substituted cucurbit[8]uril obtained from larger intermediates?

Abstract A new water soluble tetramethyl-substituted cucurbit[8]uril (Me4Q[8]) was easily isolated from cucurbit[n]uril product mixture which was synthesized by using the dimer of glycoluril and diether of dimethyl substituted glycoluril. Crystal structure analysis shows that Me4Q[8] is constructed of building blocks: three dimmers and two dimethyl glycolurils, the two dimethyl glycolurils are separated by a dimer of glycoluril. It is speculated that Me4Q[8] is degraded by a larger hexamethyl substituted Q[9] or larger intermediates.