Solvent-Free Synthesis of 2-(1H-Benzimidazol-1-ylmethyl)-4-substituted 1-Hydroxyaryl by the Two Component Mannich Reaction between 6H,13H-5:12,7:14-Dimethanedibenzo-[d,i][1,3,6,8]tetraazecine (DMDBTA) and Phenols

A new series of Mannich bases (7a-e) were synthesized with good yields, in a single pot by a two component Mannich-type reaction under solvent-free conditions from 6H,13H-5:12,7:14-dimethanedibenzo[d,i][1,3,6,8]tetraazecine (DMDBTA 1) and phenols (6a-e) at 150 ºC.The mechanism of formation of those Mannich bases and their subsequent thermal decomposition into 1H-benzimidazole (8) and respective ortho-methylated phenols (9a-f) by an o-quinone-methide intermediate are also discussed.