Reactivity and molecular recognition: Amine methylation by an introverted ester
Reactivity and molecular recognition: Amine methylation by an introverted ester
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DOI：
10.1021/ja036595q
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发表时间：
2003-12-03
影响因子：
15
通讯作者：
Rebek, J
中科院分区：
文献类型：
--
作者：
Purse, BW;Ballester, P;Rebek, J
我们报道了一种带有内向定向甲酯的宿主分子及其与一系列叔胺的反应。反应产物为主体羧酸盐与客体季铵盐的络合物。反应速度高度依赖于胺占据主体空腔的适宜性和生成的络合物的本征反应性。对2-二甲氨基乙醇合成胆碱的反应动力学进行了研究，得到反应的活化参数ΔH⧧=2 5.1±0.5kcal·m ol-1，ΔS⧧=12±2.m ol-1K-1。该络合物一旦形成，就有可能达到过渡态；与没有超分子效应的类似反应相比，速度加速估计超过2×104倍。
We report a host molecule with an inwardly directed methyl ester and its reaction with a series of tertiary amines. The reaction product is a complex of the host carboxylate with a guest quaternary ammonium salt. The rate of the reaction is highly dependent on the suitability of the amine to occupy the host cavity and the intrinsic reactivity of the resulting complex. A kinetic study of the reaction of 2-(dimethylamino)ethanol to produce choline gives the activation parameters ΔH⧧= 25.1 ± 0.5 kcal mol-1and ΔS⧧= 12 ± 2 cal mol-1K-1. The complex, once formed, is poised to reach the transition state; a rate acceleration of greater than 2 × 104fold is estimated when compared with similar reactions having no supramolecular effects.