Theoretical Studies On The Aminolysis Of Methyl Indole-3-Acetate And Thio Parathion Methyl Mechanism

Recently,the research of indole has been one of the most active areas of the heterocyclic chemistry.In particular,indole-3-methylamine has been demonstrated to be important intermediate in biological synthesis and drug synthesis since a variety of alkaloids,important physiological activity of drugs as well as phytoalexin are synthesized on the base of indole-3-methylamine.A comprehensive exploration of the aminolysis mechanism for methyl indole-3-acetate with ammonia is carried out by employing the B3LYP/6-311++G（d,p）,M06-2X/6-311++G（d,p）and MP2/6-311++G（d,p）//M06-2X/6-311++G（d,p）levels.Two alterative reaction channels of the concerted and addition/elimination stepwise processes including the uncatalyzed,base-catalyzed and acid-catalyzed aminolysis reactions are taken into consideration.Subsequently,the substituent effects and solvent effects in methanol are also evaluated at the M06-2X/6-311++G（d,p）level.The calculated results indicate that the calculated values of M06-2X level are quite close to those of MP2,the stepwise pathway has more advantages to the concerted one for all of the reaction processes and the catalyst facilitates the proton migration and decreases the energy barriers as well.It is shown that the most preferred mechanism is the acid-catalyzed stepwise process involving carboxylic of the acetic acid,the substituent of NH₂ group slightly accelerates all the aminolysis reaction processes,and the solvent effect does not remarkably change the mechanism of the reaction.Phosphate insecticides are broad-spectrum and high efficient organophosphate insecticides that have a strong contact effect on pests.As such,it is widely used in agricultural production.Therefore,here we studied the mechanism of aminolysis of organophosphorus neurotoxic agent thio methyl parathion.Based on the existing research conclusions and experimental equipment,we use the density functional B3LYP/6-311G++（d,p）and M06-2X/6-311G++（d,p）methods for the the reaction of thio methyl parathion with ammonia is systematically studied.The mechanism of the aminolysis reaction of thio methyl parathion was theoretically analyzed by density functional theory.By comparing the activation energy barriers of each path under each channel,the most excellent pathway of thio methyl parathion with ammonia is found.Solvent effect of the reaction system in acetonitrile solution was evaluated by a self-consistent field reaction field polarizable continuum model（PCM）.