Nanocrystalline ZnO was found to be a highly efficient heterogeneous catalyst for the guanylation of amines with various carbodiimides to afford N, N′, N ″-trisubstituted guanidines in excellent yields. Structurally divergent aliphatic, aromatic, heterocyclic primary and secondary amines were converted to the corresponding N, N′, N ″-trisubstituted guanidines using optimal conditions. The catalyst was easy to handle even under ...
