Study On Melt Reaction Synthesis Methodology Of Pyrazoles And 1,2,3-Triazoles

With the increasing attention to environmental protection,the search for clean and efficient synthesis methods has become an important challenge in the field of heterocyclic compounds preparation.In chemical reactions,the use of environmentally friendly solvents or even no solvents has become the main development direction of green synthesis of heterocyclic compounds.Based on green chemistry,this paper studied the green synthesis methods of two types of azoles with excellent application properties: 1,3,5-trisubstituted pyrazoles and1,4-disubstituted-1,2,3-triazoles:(1)Taking different substituted hydrazines and β-carbonyl ketones as the reaction substrates,and the effects of reaction temperature or time on the yield were explored under the conditions of catalyst-and solvent-free.With the optimal reaction conditions determined,21 kinds of 1,3,5-trisubstituted pyrazoles were received.It can be seen that this method has strong substrate applicability and easy operation.;in addition,compared with the reaction effects of 5 common solvents and solvent-free conditions so that more excellent reaction results under solvent-free conditions were emerged.(2)Using all kinds of terminal alkynes and azides as raw materials,the effects of different catalysts and catalytic amounts were studied under solvent-free conditions.Also with the optimal reaction conditions determined,211,4-disubstituted-1,2,3-triazole derivatives were synthesized conveniently and efficiently by Click reaction.It is gratifying that most of the yields of the target products are above 90%,and the purity is also close to 100%.In conclusion,this paper studied and developed new synthesis methods of the above two kinds of azole derivatives.Compared with the literature method,this synthesis method can effectively avoid the pollution of products and environmental damage caused by the use of solvents or heavy metal catalysts,and has the characteristics of short reaction time,high atom utilization rate,simple,efficient and green economy,which conforms to the requirements of green chemistry and atomic economy.