Mono-<i>N</i>-methylation of Functionalized Anilines with Alkyl Methyl Carbonates over NaY Faujasites. 4. Kinetics and Selectivity
作者:Maurizio Selva、Pietro Tundo、Tommaso Foccardi
DOI:10.1021/jo048076r
日期:2005.4.1
transesterification reactions. Aromatic substituents, however, modify the relative reactivity of amines 1−4: good evidence suggests that, not only steric and electronic effects, but, importantly, direct acid−base interactions between substituents and the catalyst are involved. Weakly acidic groups (OH, CH2OH, CONH2, pKa ≥ 10) may help the reaction, while aminobenzoic acids (pKa of 4−5) are the least reactive
在的NaY八面沸石的催化剂存在下,双官能的苯胺的反应(1 - 4:XC 6 H ^ 4 NH 2 ; X = OH,CO 2 H,CH 2 OH,和CONH 2)与甲基碳酸烷基酯[MeOCO 2 R':R'= Me或MeO(CH 2)2 O(CH 2)2 ]以非常高的单-N-甲基选择性(XC 6 H 4 NHMe最高可达99%)和化学选择性进行,其他亲核功能(OH,CO 2 H,CH 2 OH,CONH2)完全保存,不受烷基化和/或酯交换反应的影响。芳族取代基,然而,修饰胺的相对反应性1 - 4:良好的证据表明,不仅空间和电子效果,但是,重要的是,取代基和所述催化剂之间的直接酸-碱相互作用的参与。弱酸性基团(OH,CH 2 OH,CONH 2,P ķ一个≥10)可有助于反应,而氨基苯甲酸(对ķ一个4-5)是至少反应性的底物。溶剂的极性也会影响反应,在二甲苯中比在极性更大的二甘醇二甲醚中要快