A Facile Route to Substituted Bidentate and Tridentate Ligands Capable of Forming Six-membered Chelate Rings with Transition-Metal Ions

A facile one-pot synthesis of mono(hpp)- or di(hpp)-substituted N-heterocyclic ligands from halogenated N-heterocycles and 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (H-hpp) is presented. N,N-Bidentate and N,N,N-tridentate ligands incorporating electron-donating and electron-withdrawing substituents can also be readily synthesized using this method.