Studies On The Metal Catalyzed Synthesis Of Several New Heterocyclic Compounds

Since the discovery of Sonogashira coupling reaction, it has been widely investigated and applied in the synthesis of diverse heterocyclic compounds, natural products, photoelectric materials as well as nano molecular devices. Sonogashira reaction was characterized by the mild conditions, simple operation and efficiency. However, there are some challenges remained to be resolved, one of which is the exploration of novel inexpensive, environment friendly and efficient catalyst systems. Additionally, to find new efficient catalysts for coupling of unreactive chlorinated arenes with terminal alkynes is also the focus within this field. In view of the two aspects, we carried out the studies on the metal-mediated carbon-carbon bond formation.In the first section, recent research of Sonogashira coupling reactions was reviewed briefly in both the improvement on catalysts and the coupling reaction of unreactive chlorinated arenes.In the second part, we studied the Sonogashira coupling reaction of 1,4-dichloro- phthalazine with various terminal alkynes, recognizing the important bioactivity of phthalazine derivatives in the antimicrobial, antiviral reactivity and plant growth adjustment. Through the optimization of reaction conditions such as catalyst, ligand, sovent, base and temperature, the coupling reaction catalyzed by the FeCl3/C can give moderate yields. Four new phthalazine derivatives were synthesized and fully characterized by IR, 1H NMR, 13C NMR, MS, elemental analysis and X-ray diffraction techniques.In view of the unique structure and bioactivity of pyrimidine derivatives, the third section is the evaluation of 2-amino-4,6-dichloropyrimidine coupling with different terminal alkynes. It was found that iron catalyst does not work well with this system giving unsatisfactory yields, but the Pd/C catalyst is a good choice for improving this coupling reaction. Four new pyrimidine derivatives were obtained and fully identified by IR, 1H NMR, 13C NMR, MS, elemental analysis and X-ray diffraction techniques.In summary, the studies about the Sonogashira coupling reaction catalyzed by iron are of significance for the exploring and of new metal source in coupling reactions.