Synthesis And Biological Activity Of Nitrogen-containing Fused Heterocyclic Compounds

In recent decades,nitrogen-containing fused heterocyclic compounds as nitrogen-containing compounds have played a very important role in the chemical and biological medicine fields,and there are a lot of nitrogen-containing compounds in nature,such as:vitamins,alkaloids,hormones,nucleic acids,etc.Because of its unique biological activity and physicochemical properties,nitrogen-containing fused heterocyclic compound have widely used in medicine,pesticides,new materials and other fields,and have gradually become a hot spot and focus of modern organic synthesis research.This work combined the new organic synthesis method,and to construct a nitrogen-containing fused heterocyclic ring by using copper salt and sulfur powder as promoters or catalysts.The main work of this paper is as follows:?1?The reaction of transition metal copper induced coupling to the formation of pyrido[2,1-b]quinazoline-11-one was investigated.Through the selection of different copper salts,different oxidants,different solvents,different temperatures and the amount of feed,the reaction conditions with the best reaction and the best effect were selected,and the synthesis of pyridylquinazolinone and its derivatives was realized.In the study of the reaction mechanism.Combined with the literature of related double-directed C-H activation and lots of mechanism research experiments,it is proposed that the transition metal copper promotes the construction of pyridoquinazolinone.?2?The reaction of metal-free elemental sulfur oxidation to imidazole[1,5-a]pyridine was studied.In terms of conditions,the optimal reaction conditions were explored by factors such as pyridine derivatives,benzylamine,sulfur powder,solvent and temperature.We have confirmed the best condition:1.0 eq?0.2 mmol?of2-pyridylacetate,1.2 eq?0.24 mmol?of benzylamine,3.0 eq?0.6 mmol?S₈,1 ml of DMSO as a solvent,and the reaction was stirred at 110°C for two hours.Through the extension of the substrate for the ethyl pyridine derivative and the benzylamine derivative,we successfully synthesized 29 different products with a maximum yield of 92%.We have developed a new metal-free method for the efficient construction of imidazopyridine.?3?The biological activity of the two types of nitrogen-containing fused heterocyclic compounds synthesized by tyrosinase inhibition was judged by comparing the difference between the inhibition of tyrosinase activity by two types of nitrogen-containing fused heterocyclic compounds and curcumin.The tyrosinase inhibitory activity test of the compound showed that the inhibitory activity of the synthesized compound against tyrosinase was generally higher than that of curcumin.Compounds containing a pyridine structure have strong tyrosinase inhibitory activity,with the value for further research.