Cesium Hydroxide-promoted Synthesis Of 3-chalcogenyl-indoles

Indoles are important heteroatomic compounds because of the wide application in pharmaceutical engineering,functional material and agriculture.The development of facile methods allowing rapid construction and functionalization of these motifs has attracted immense interest.3-sulfenylindoles are common S-containing indole derivatives.They are not only importment structural motifs in drugs and agrochemicals,but also significant fine chemical raw materials.In the past few decades,a number of significant synthetic methods for the construction of 3-sulfenylindoles have been developed by employing various sulfenylating agents such as thiols,disulfides,sulfonic acid and its derivatives,N-thioimides,et al.Despite the advances,facing us are problems such as harsh reaction conditions,difficultly obtained materials and complicated procedure.While the reparts on the systhesis of 3-Selenylindoles and 3-tellanylindoles are rare.In this study,we adopted cesium hydroxide monohydrate as base or catalyst for the systhesis of 3-chalcogenyl-indoles,using indoles and disulfides,diselenides or ditellurides as starting materials.The main results are as follows:(1)The reaction of indole and diphenyl disulfide was used as a model reaction to explore the influence of base,solvent,time,temperature and amount of catalyst to the reaction.Optimal conditions are obtained as follows:CsOH·H2O(1.5 equiv.),DMSO,room temperature,3 h.And we applied the method to various indoles and different diaryl disulfides,and founded that all the reactions afford the corresponding products in the yield of 30%-99%.And we also investigated the mechanistic pathway of this reaction.(2)The reaction of indole and diphenyl diselenide was used as a model reaction to explore the influence of base,solvent,time,temperature and amount of catalyst to the reaction.Optimal conditions are obtained as follows:CsOH·H2O(0.5 equiv.),CH3CN,room temperature,0.5 h.And we applied the method to various indoles and different diaryl diselenides,and founded that all the reactions afford the corresponding products in the yield of 45%-99%.And we also investigated the mechanistic pathway of this reaction.(3)The reaction of indole and diphenyl ditelluride was used as a model reaction to explore the influence of catalyst,solvent,time,temperature and amount of catalyst to the reaction.Optimal conditions are obtained as follows:CsOH·H2O(0.2 equiv.),DMSO,room temperature,3 h.And we applied the method to various indoles and different diaryl ditellurides,and founded that all the reactions afford the corresponding products in the yield of 38%-94%.And we also investigated the mechanistic pathway of this reaction.In this thesis,we investigated cesium hydroxide promoted the synthesis of 3-chalcogenyl-indoles from indoles and disulfides,diselenides or ditellurides.The advantages of the reaction include:easy operation,mild reaction conditions,stable and easily obtained materials,environmental friendliness,high regioselectivity.This method provides a new protocol for the synthesis of 3-chalcogenyl-indoles.