Studies On The Synthesis Of 1,2,3-Triazole In Ionic Liquid

1,2,3-Triazoles are a kind of very important nitrogen-based heterocycles,which are widely used in pharmaceutical,pesticide,biological,polymer materials and chemical industry because of their special aromatic structure and strong stability.There are several methodologies for the synthesis of 1,2,3-triazoles,mainly based on 1,3-dipolar cycloaddition between azides and alkynes under thermal conditions as well as metal catalysts（such as copper,ruthenium and palladium）.On the basis of the seniors’ research,this paper further explored the methods for the synthesis of 1,2,3-triazoles.Firstly,we synthesized 1,2,3-triazoles by reacting aldehydes with azides using ionic liquid [Bmim]PF₆ as reaction medium,which is a kind of green solvent,and KOH as the catalyst.The method bears the benefits of simple operation and easy recycling.In the process,the reaction between aldehydes and azides was catalyzed by the in situ generated [Bmim]OH from KOH interacting with [Bmim]PF₆.In general,alcohols are relatively more stable than aldehydes.Therefore,we selected alcohols as the reaction substrates,which could be oxidized into corresponding aldehydes by 2-iodoxybenzoic acid（IBX）.The in situ generated aldehydes could interact with azides to form the corresponding 1,2,3-triazoles in ionic liquid.In combination with the application of nano copper in the click reaction,we obtained the nano copper（sized of 200 nm because of conglomeration）by reducing CuSO4·5H2O with zinc powders.Then the prepared nano copper was used to catalyze the 1,3-dipolar cycloaddition between alkynes and azides in [Bmim]PF₆,which had advantages of simple operation,broad spectrum of substrates and recycling for consecutive runs.Although the size of prepared nano copper was slightly larger,the catalytic efficiency was much higher than the general copper and effectively solved the problem of recycling at the same time.The preparation process was relatively simple without adding stabilizing agent.Finally,we have designed a new route to synthesize a dozen 4H-1,2,4-benzothiadiazine-1,1-dioxides derivatives with simple operation,high yield and purity.The inhibiting effects on HepG-2 cell were evaluated with MTT protocol,which showed that the target compounds could inhibit the growth of tumor cells in different degrees and this kind of compounds deserved further study.