Study On The Synthesis Of Quinoline[3,4-b] Quinoxalinones And Pyrrolo[3,4-b] Quinoxalinones

The dissertation mainly involves the following two aspects: 1.the synthesis of quinoline[3,4-b] quinoxalinones;2.the synthesis of pyrrolo[3,4-b] quinoxalinones.1.The synthesis of quinoline[3,4-b] quinoxalinones.The quinoxaline compounds are very important heterocyclic compounds.The two carbon atoms on the phenyl ring are replaced by nitrogen atoms.The quinoline compounds are also very important nitrogen heterocyclic compounds.They are widely used in medicine,sterilization,insecticide,weeding,plant growth regulation,and photoelectric materials due to their biological activities such as antiviral,antimicrobial,antitumor activities,and activities against some pathogenic microorganisms.Previous synthesis methods for these compounds are using precious metals and higher reaction temperatures and lower yields.Therefore,development of new methods for synthesis of quinoline derivatives is very important.In this thesis,we wish to report a facile and direct intramolecular oxidative C-H amidation reaction for the synthesis of quinolino[3,4-b]quinoxalin-6(5H)-ones in moderate to excellent yields starting from readily available materials by tethering the adjacent N-methoxyamide and aryl portions in the presence of phenyliodine(III)bis(trifluoroacetate)at room temperature.These compounds combine the advantages of quinoxalines and quinolines,making them more widely application in medicine.This metal-free approach is a valuable addition to the traditional methods for the preparation of these molecules.2.The synthesis of pyrrolo[3,4-b] quinoxalinones.Pyrrole compounds widely exist in nature.Many alkaloids(such as caramate,monocrotaline)and drugs(such as clotrimazole,miconazole,econazole)contain pyrrole building blocks.In this part,a Cu-catalysed convenient intramolecular direct amidation and successive oxidation reaction of benzylic C(sp3)-H bond was developed for the direct synthesis of pyrrolo[3,4-b]quinoxalinones in one step in moderate to good yields.The reaction proceeded with a novel strategy,which is entirely different from the previous synthesis methods starting from readily available starting materials,and made it as an alternative,valuable,important,and practical route to the traditional methods.Compared with other C(sp3)-H functionalization,this method not only avoids the using of noble metal catalysts such as palladium,rhodium,rythenium but also reduces the costs,improves the economy of the atoms.