应用AM1方法研究3-芳胺甲烯基-6-烷基-5,6-二氢-二氢吡喃-2,4'-二酮的催化氢化反应机理

以3-(对甲基)苯胺甲烯基-6-甲基-5,6-二氢-二氢吡喃-2,4'-二酮为例,用半经验量子化学方法和UHF/6-311G水平上的从头算研究了3-芳胺甲烯基-6-烷基-5,6-二氢-二氢吡喃-2,4'-二酮类农药化合物催化氢化的反应机理.通过对反应物、中间物和产物的生成热、净电荷、键序以及前线轨道能量的计算和分析认为标题化合物的催化氢化反应不仅发生了碳碳双键的加成反应,还同时发生了碳氮键的催化氢解反应.

AM1 Study on the Mechanism of Catalytic Hydrogenation of 3-Anilinomethylidene-6-alkyl-5,6-2H-dihydropyran-2,4-diones

p Methyl) anilinomethylidene 6 methyl 5,6 2H dihydropyran 2,4 dione was selected as model reactant to study the mechanism of catalytic hydrogenation of 3 anilinomethylidene 6 alkyl 5,6 2H dihydropyran 2,4 diones by means of the AM1 and UHF/6 311G methods. The molecular informations such as heats of formation, net charges, bond orders, the values of frontier orbital energies, composition, their proportion and bonding contribution were acquired and analyzed. Thus the possible reactive sites were put forward and the reaction mechanism was postulated via two steps. The postulated intermediates and products of the two steps were also computed by AM1 method. Their heats of formation and energies of HOMO/LOMO/LUMO indicate that the mechanism of catalytic hydrogenation of 3 anilinomethylidene 6 alkyl 5,6 2H dihydropyran 2,4 diones is not only a hydrogenolytic addition on CC bond but also a hydrogenolytic cleavage of the C_N bond of anilinomethylidene.