Synthesis Of 4,5-Difunctionalized Pyrazoles

Pyrazoles and their derivatives constitute an important class of compounds that are extensively used in the agrochemical,material,and pharmaceutical industry.Synthesis of pyrazoles has received considerable attention from organic chemists.The thesis consists of the following two main parts:The first chapter summarized the application of pyrazoles as a class of important heterocyclic compounds in the fields of medicine and agriculture.Subsequently,several common methods of pyrazoles synthesis are introduced.The second chapter introduces the aminopyrazoles derivatives displays diverse biological activities and its synthesis methods.A regioselective synthesis of 4,5-bifunctionalized pyrazole from N-tosylhydrazones was developed in acid condition.A series of 5-amino-4-cyanopyrazoles were synthesized in good yield.Then we investigated any other active methylene compounds such as 1,3-cyclohexanedione,acetylacetone and ethyl cyanoacetate under the same conditions.In addition,the method has been successfully applied to the formal synthesis of ibrutinib.