Polythene glycol (PEG) as a reusable solvent system for the synthesis of 1,3,5-triazines via aerobic oxidative tandem cyclization of benzylamines and N-substituted benzylamines with amidines under transition metal-free conditions

A green and highly efficient protocol for the synthesis of 1,3,5-triazines from benzylamines and N-substituted benzylamines with amidines in PEG-600 has been developed. This protocol is transition-metal free, phosphine ligand free and uses inexpensive, easily available molecular oxygen (O-2) as an oxidant. A series of 1,3,5-triazines derivatives were synthesized in good to excellent yields in a shorter reaction time. The ease of the product separation and reusability of PEG-600 makes it more environmentally benign and economically affordable for gram-scale synthesis.