Investigation On Methodology For The Green Synthesis Of Nitrogen-containing Heterocyclic Compounds

Heterocyclic chemistry is an important part of modern organic chemistry and it has always been one of the most studied areas.A large number of N-heterocycle compounds are widely used in various fields such as medicine,pesticide,material and organic dye for their wide range of physiological activities and diverse functions.Therefore,the synthesis of N-heterocycle compounds has been a hot topic of concern and research by organic synthesis chemists and pharmacologists.With the increasingly prominent environmental problems,people have higher expectations for a greener organic synthesis method.The method of solvent-free organic synthesis has the advantages of solvent-free contamination,short reaction time,high selectivity,easy operation and convenient post-treatment.It has always been encouraged by society and is favored by organic synthesis chemists.The main purpose of this thesis is to study the synthesis of pyrazoles,pyrazolones,pyrazolo[2,3-c]pyrones,pyrano[2,3-c]pyrazoles,4,5-2H-pyridazinones,phthalazinones and other nitrogen-containing heterocyclic compounds with high research and application value.Through the optimization of temperature,time,ingredient ratio,solvent and other conditions of the melting reaction,the green,efficient and simple synthesis method was successfully applied to the synthesis of six kinds of nitrogenous heterocyclic compounds.The synthesis of pyrazoles,pyrazolones,pyrazolo[2,3-c]pyrones,pyrano[2,3-c]pyrazoles,4,5-2H-pyridazinones,phthalazinones and methods were systematic researched,according to the content the thesis is divided into the following five parts.A rapid and efficient solvent free melting method for the synthesis of 3,5-disubstituted pyrazole compounds was successfully developed.The method is highly efficient,simple,high yield and expected to replace the traditional method for the preparation of this kind of compound.Nine kinds of pyrazolone derivatives were synthesized rapidly and without any solvent by melting method.The method has the advantages of environment friendliness,simple operation and convenient post-processing.The synthesis of 1-phenyl-3,4-dimethylpyrazolo[2,3-c]pyrone was studied by the one-pot solvent-free method.Under the optimal reaction conditions,14 pyrazolo[2,3-c]pyrone derivatives were synthesized.The mechanism of the reaction was further explored,and an intermediate which was not reported in literatures was isolated.Further we forecast a new reaction mechanism.The method has low substrate tolerance,no solvent pollution and more environmental protection.A rapid and efficient one pot four component method for the synthesis of pyrano[2,3-c]pyrazole derivatives by substituted phenylhydrazine,ethyl acetoacetate,substituted benzaldehyde,two propylene nitrile as raw material in solvent-free conditions and three triethylamine as catalyst.The method is very easy to operate and convenient for post-processing.Attempt to apply the solvent-free melting method to the synthesis of1-phenyl-4,5-2H-pyridazinone,and 6 kinds of 4,5-2H-pyridazone derivatives were successfully synthesized.The method does not use any catalyst and organic solvent,having the advantaged of short reaction time,high yield,which is expected to replace the synthesis route of angelica lactone as the starting material.Has successfully applied the method of solvent-free and catalyst-free to the synthesis of2-phenyldiazaphthalen-1-one.Through the optimization of conditions,14 kinds of phthalazinone derivatives were synthesized under the optimal reaction conditions.Compared with the traditional synthesis methods using catalysts and solvents,the method is more green,economical,high yield,fast reaction,simple operation and convenient post-processing.