Template-directed synthesis of cucurbituril analogues using propanediurea as a building block

Abstract

Two novel cucurbituril-like macrocycles, TD[4] and TD[5], were prepared from the condensation of propanediurea and formaldehyde using CaCl₂ and BaCl₂ as templates, respectively, featuring convenience and low cost. The two hosts show excellent thermostability and their structures were characterized by ¹H NMR, HRMS and single crystal X-ray diffraction.