One-pot formation of aromatic tetraurea macrocycles

Treating derivatives of m-phenylenediamine having different electron-richness and reactivities with triphosgene in the presence of triethylamine led to aromatic tetraurea macrocycles in high yields. Factors important for efficiently forming these macrocycles include the molar ratio (2:1) between the diamine and triphosgene, reaction temperature (-75 °C), and solvent (CH₂Cl₂). By controlling the order and rate for adding diamines, tetraurea macrocycles consisting of two different types of monomeric residues have also been obtained in high yields.