Our cyclicurilarene receptor family has been extended by coupling of 2,4-dimethylglycoluril with bis(bromomethyl)-substituted dimethoxybenzene through nucleophilic substitution, yielding macrocycles with conformational flexibility that can adapt to different-sized substrates, resembling bambusurils. Anti/syn-configurations of the two glycoluril units in “Ding”-shaped cyclicurilarenes induce distinct acetonitrile positions in the solid state, and inward-oriented glycoluril forms intracavity hydrogen bonds with alanine derivative in chloroform. Four- and six-membered cyclicurilarenes featuring alternating dimethoxybenzene and glycoluril units were synthesized.
Wen et al. (Wed,) studied this question.