The
intermolecular cyclization reactions of
N-tosyl-ethylenediamine with glyoxal promoted by transition metal acetate at different ratios gave three
N-heterocyclic compounds. The ligand in compound
contains one
N-heterocycle, which is formed by a one-pot three-component reaction. In compound
, two imidazolidine rings and one piperazine ring are fused together to form a tricyclic skeleton by a one-pot five-component reaction. Two 1,3,6-triazabicyclo[3.3.0]octanes are connected by one C–C bond to form the skeleton of
, which is constructed from a one-pot nine-component reaction. It revealed that the key factor for the preparation of these compounds is the ratio of starting materials, as well as the presence of corresponding transition metal acetates.