The Design And Synthesis Of New Pyrazoles Derivatives

The research of heterocyclic compounds which always play a very important role in theories and practical application has been one of more rapid sections in the organic chemistry. Most biologically active compounds are heterocyclic organic compounds, which have a ring structure containing atoms such as sulfur, oxygen, or nitrogen, in addition to carbon. Over half of all known compounds and large number of pharmaceutical products are heterocyclic in nature.Pyrazole derivatives are very important nitrogen-containing compounds, which have broad-spectrum potential biological activity and intensively applied in pharmaceutical and agrochemical industries. Pyrazole derivatives can treat many diseases, and they can be made for pesticides, herbicides, acaricides which show their multifunction and efficacy. Additionally, the heterocyclic compounds with1,2,4-oxadiazole also have attracted more attention due to their potent activities such as antibacterial, diminish inflammation, antidepressants, antiviral, they also are the intermediates of some heterocyclic drugs and natural products. Therefore, we obtained a series of novel heterocycles starting with pyrazole bearing formyl group by introduction1,2,4-oxadiazoles into pyrazole ring and refined the imine (C=N) double bond by1,3-dipolar cycloaddition reaction, respectively.The thesis includes three major parts:The first part is about literature review:In this part, The important synthetic methods, physiological and pharmacological activities of pyrazole derivatives that have been studied were explicated systematically; also introduced a more comprehensive properties and synthetic methods of thiazole; and briefly elucidated1,3-dipolar cycloaddition reaction.The second part is about experimental content. Major works as follows:1. Synthesis and characterization of1,4-diaryl-3-benzoyl-pyrazoles;1,3,4-Trisubstituted pyrazoles has been accomplished by1,3-dipolar cycloaddition of α.β-unsaturated ketones and3-arylsydnones in dry xylene. 2. Synthesis and characterization of1-(4-aryl-2-thiazolyl)-3-aryl-5-(1-aryl-3-methyl-4-1,2,4-triazolyl-pyrazole-4-yl)-pyrazoli nes1-Phenyl-3-methyl-4-formyl-5-(1,2,4-triazolyl)-pyrazoles were obtained by the reaction of1-Phenyl-3-methyl-5-chloro-4-pyrazole formaldehyde with1,2,4-triazole, then the reaction of the compuonds with1-arylethanones afforded1-aryl-3-(2-aryl-1,2,3-triazol-4-yl)-2-propen-l-ones, then underwent condensation with thiosemicarbazide afforded the key intermediates1-aryl-5-(1-phenyl-3-methyl-4-1,2,4-triazolyl-pyrazole-4-yl)-1-thiocarbamoyl-pyrazoline s, the condensation of these compounds with2-bromo-1-arylethanones resulted in the formation of pyrazoline derivatives.3. Synthesis and characterization of bis[1-phenyl-3-methyl-4-(3,4-diaryl-1,2,4-oxadizole-5-yl)]-5,5’-phenoxy parazole1-Phenyl-3-methyl-5-chloro-4-pyrazole formaldehyde and hydroquinone reaction to generate bis-pyrazole aldehyde, then the reaction of the compounds with aniline afforded the key intermediates Schiff bases, the condensation of these compounds with chlorobenzoldoxime resulted in the formation of bis[1-phenyl-3-methyl-4-(3,4-diaryl-1,2,4-oxadizole-5-yl)]-5,5’-phenoxy parazole.Above all, the structures of the new compounds were confirmed by elememtal analysis, IR,1H NMR and MS spectral data, and their spectral properties were also discussed.