Synthesis And Technology Of Some Nitrogen-Containing Heterocyclic Compounds

In the fields of fine chemicals, such as pesticide and medicine, etc., hetrocyclic compound containing nitrogen play an important role, and have been the focus of the research for many years. In this thesis, the recent advances in the studies on the development and synthesis of pyridine and pyrazole derivatives were reviewed, and 4-amino-2-chloropyridine, 2-chloro-6-methylnicotinicacid as well as 3-aminopyrazole were chosed as researh topics.Part one: Synthesis of 2-chloro-4-aminopyridine. In this section, the advantages and disadvantages of various synthetic methods were compared and cheap isonicotinic acid has been chosed as raw materials to prepare 2-chloro-4-aminopyridine by way of nitrogen oxide, chlorination, ammonolysis and Hofmann degradation. The total yield is about 70%. Compared with the traditional method with 2-chloropyridine as raw materials, the route presentd here is more environment-friendly, simple and easy to achieve.Part two: Synthesis of 2-Chloro-6-methyl-nicotinic acid. By comparison among different routes, we have selected cheap acetone and ethyl formate as raw materials, through cyclization, chlorination and hydrolysis to prepare the target compound. Through the optimization of the process, the total yield is 47%. Compared with biological transformation, microwave and other methods, the route is simple and low cost.Part three: Synthesis of 3-amino-pyrazole. In this section, the advantages and disadvantages of various synthetic methods were compared and cheap 2-chloroacrylonitrile has been chosed as raw materials through "one step" synthesis. The reaction temperature and the ratio of raw materials were detailed investigated. In addition, a continuous extraction device was built to realize fully extraction of 3-amino-pyrazole. It is not only easy to implement but also improve the yield, which is about 70%.