Aim and Objective: The late transition metal complexes with five-membered heterocyclic
mono-imine ligands have attracted much attention because of their potential application in olefin polymerization
catalysis. In order to increase the coordination ability of heteroatom N and S to center metals, CH3 group
was introduced into the side arm of pyrrole imine and thiophene imine respectively, to get two series of novel
five-membered heterocyclic imine compounds, mono(imino)pyrroles and mono(imino)thiophenes.
Materials and Methods: Two series of novel five-membered heterocyclic compounds with the mono-imine
group were synthesized from the p-toluene sulfonic acid catalyzed Schiff base condensation of aromatic
amines and 2-acetylpyrrole/ 2-acetylthiophene respectively, using CH3 group to substitute the common H atom
on the side arm of pyrrole imine/ thiophene imine.
Results: All the heterocyclic mono-imine compounds were characterized adequately by means of 1H NMR, 13C
NMR, FT-IR, elementary analysis, as well as X-ray crystallographic diffraction. The reactivity differences
between two precursor 2-acetylpyrrole and 2-acetylthiophene with aromatic amines were compared and
discussed in detail.
Conclusion: Compared to traditional heating methods, the solvent-free microwave irradiation seemed more
efficient to prepare these series of five-membered heterocyclic mono-imine compounds, which resulted in a
higher yield and cleaner product.