Synthesis of macrocyclic and linear benzylimidazolidine oligomers from solvent free aromatic Mannich-type reaction

The reaction between the phenolic Mannich bases 1,3-bis[2'-hydroxybenzyl]imidazolidines and the Mannich intermediary macrocyclic aminal 1,3,6,8-tetraazatricyclo[4.4.1.1(3,8)]dodecane (TATD) was studied under solvent-free conditions. It was established that the major product is a heterocalixarene-type Mannich base, and three linear benzylimidazolidine oligomers were identified as minor products. The formation of these oligomers is analyzed in the present Letter, and the reaction mechanism is proposed. (C) 2015 Elsevier Ltd. All rights reserved.