Solvent-free Mannich-type reaction of tetraazatricyclododecane (TATD) with phenols

Solvent-free Mannich-type reactions between the macrocyclic aminal 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and phenols indicate that the activation of the aromatic ring is critical for controlling the course of reaction. Activated rings form N,N′-bis(2-hydroxybenzyl)ethylenediamine (tetrahydrosalens), and weakly activated rings form Mannich bases consisting of 1,3-bis[2′-hydroxybenzyl]imidazolidine. When the reaction is conducted using β-naphthol, a Mannich-type reaction occurs followed by a retro-Mannich-type reaction that forms 1,1′-methylene-bis(2-naphthol). The solvent-free reaction between 1,3-bis[2′-hydroxybenzyl]imidazolidine Mannich bases and the macrocyclic aminal 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) allows Mannich bases with high molecular weight to be obtained in a controlled manner.