Synthesis Of Enamine-Containing Dibenzo[b,d]azepines And Study On The Tautomerism

Nitrogen-containing heterocyclic compounds have been widely used in the synthesis of drugs and pesticides because of their unique biological activities and pharmacological properties.Enamine and imine,as two important nitrogen-containing heterocyclic compounds,are significant intermediates in the synthesis of organics and drugs,which are often used in the synthetic strategy of asymmetric amine.Meanwhile,enamine and imine are a pair of tautomers.Enamine is unstable,which can transform into imine easily.Therefore,looking for an economic and efficient synthesis tactics of enamine and imine can not only provide new methods for synthesis of nitrogen compounds,but also can deepen the research of tautomerism.What's more,it plays an important role in the explanation of organic reaction mechanisms and biological activities.So far,there have been few reports about the research of enamine and imine dibenzo-diazepines.However,the study of synthesis and tautomerism of these compounds is very necessary.We have successfully implemented the synthetic strategy of imine dibenzo-diazepines.Based on this work,the goal for the synthesis of enamine dibenzo-diazepines has achieved,by utilizing palladium as catalyst.Up to now,there are some several breakthroughs have been done.A simple and efficient palldium-catalyzed method has been developed for the synthesis of enamine dibenzo-diazepines.Using palladium acetate as the catalyst.,2'-bromo-[1,1'-biphenyl]-2-amine and 1,2-diphenyethyne as the starting materials,target products 6,7-diphenyl-5H-dibenzo[b,d]azepine are well performed under mild conditions.Through the optimization of reaction conditions,the side reaction inhibited effectively,and giving enamine in excellent yield.The universality of the reaction was studied,and the results show that the target products were well obtained by most substrates in this reaction system.As we mentioned above,enamine can convert into imide easily.The tautomerism is caused by the transfer of proton.And environment has a great influence on it.We observed the enamine and imide tautomerism by regulation of temperature,solvent and the PH of mediums.The synthesis of 6,7-diphenyl-5H-dibenzo[b,d]azepine expands the synthetic methods of the dibenzo[b,d]azepine.The discussion about 6,7-diphenyl-5H-dibenzo[b,d]azepine and 6,7-diphenyl-7H-dibenzo[b,d]azepine futher deepens the understanding of tautomerism as well.