Theoretical Study On The Reaction Mechanism Of The Synthesis Of Pyrrole Derivatives And Pyrazole Derivatives

In this paper, we summarize the synthesis significance of pyrrole derivatives andpyrazole derivatives as well as the research status at home and abroad. We select two theorysubjects for this, one is the theory study of the reaction mechanism of synthesis of pyrrolederivatives, the second is the theory study of reaction mechanism to synthesize pyrazolederivatives, we have done the theory study for each of the four synthesis reaction mechanism,in order to explore the rules of the synthesis of pyrrole derivatives and pyrazole derivatives.The main methods: B3LYP/6-311++G**implemented in Gaussian09package is used tolocate all the stationary points along the reaction pathways. Full optimization and vibrationalanalysis are done for the stationary points on the reaction profile. In order to explicitlyestablish the relevant species, the intrinsic reaction coordinate (IRC) is also calculated for allthe transition states appearing on the energy surface profile.According to the four synthesis reaction mechanisms of the the synthesis of pyrrolederivatives from cyclopropane derivatives and hydrazide, we can predict that the reactionshave the same mechanism, these reactions have four steps.(1) Cyclopropane derivatives reactwith hydrazide to generate a intermediate product (INT1) through the transient state(TS1).(2)(INT1) generates a intermediate product (INT2+H2O) through a dehydration reaction.(3)INT2generates another intermediate(INT3) product through a cyclization reaction.(4)Through the transition state (TS4),the INT3happens a hydrogen transfer reaction,the finalproduct generated is (P).According to the four synthesis reaction mechanisms of the synthesis of pyrazolederivatives from diyne compounds and hydrazines. We can predict that the reactions have thesame mechanism, these reactions have five steps.(1) Diyne compounds reacts withhydrazines to generate a intermediate product (INT1) through the transient state(TS1)(2)(3)(INT1) generates an intermediate(INT3) through two hydrogen transfer reactions in turn.(4)Through the transition state(TS4), INT3generates the intermediate (INT4) by an isomerization reaction.(5) INT4generates the final product (P) throughr a cyclization reaction.