The reaction mechanism of the title reaction was proposed on the bases of the kinetic study. The reaction takes place in two stages considerably differing in rates. In the first, faster stage, the anion of initial substance cyclizes to 1-methyl-3-benzoyl-2-thioxo-4-quinazolone. The reaction is reversible, the concentration of 1-methyl-3-benzoyl-2-thioxo-4-quinazolone decreases with increasing concentration of methanolate. In the second stage, the benzoyl group rearrangement in the given substance from nitrogen to sulfur and subsequent methanolysis to 1-methyl-2-thioxo-4-quinazolone take place. The rate-determining step is the methanolysis for [CH3O(-)] < 4 . 10-3 mol l-1 and the benzoyl group rearrangement for higher methanolate concentrations.
在动力学研究的基础上,提出了标题反应的反应机理。该反应分为两个阶段,速率相差较大。在第一阶段中,初始物质的负离子环化成为1-甲基-3-苯甲酰基-2-硫代氧杂-4-喹唑酮。该反应是可逆的,1-甲基-3-苯甲酰基-2-硫代氧杂-4-喹唑酮的浓度随着甲醇酸根浓度的增加而减少。在第二阶段中,给定物质中的苯甲酰基从氮原子重排到硫原子,并随后发生甲醇解作用,生成1-甲基-2-硫代氧杂-4-喹唑酮。速率决定步骤是甲醇解反应,当[CH3O(-)] < 4 × 10^-3 mol L^-1 时,是苯甲酰基重排反应,而在更高的甲醇酸根浓度下则是甲醇解反应。