Formation, stability, and protonation of dihydropyridines. A MINDO/3 study
Formation, stability, and protonation of dihydropyridines. A MINDO/3 study
复制标题
二氢吡啶的形成、稳定性和质子化。
DOI：
10.1021/ja00484a004
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发表时间：
1978
影响因子：
15
通讯作者：
R. Pearlman
中科院分区：
文献类型：
--
作者：
N. Bodor;R. Pearlman
用MINDO/3研究了各种二氢吡啶异构体和相关化合物的形成、稳定性和行为。7个二氢异构体的稳定性顺序为：1，4> 3，4> 1，2> 2，5> 2，3> 2个双环结构。发生二氢吡啶的质子化，优先产生烯胺盐。所有这些过程的计算结果与实验观测结果符合得很好。1，4-与1，2-二氢吡啶的相对稳定性与吡啶及其1-甲基衍生物的相对稳定性相同。结果表明，有利的电子相互作用（超共轭，同芳香性）确实可以解释增加的稳定性的1，4-二氢异构体。虽然二氢吡啶类化合物2在生物体系中具有重要的作用，特别是NAD-NADH参与了生物的氧化还原反应，但简单的二氢吡啶类化合物由于其易氧化和各种加成反应以及缺乏简便的制备方法而没有得到广泛的研究。
A detailed MINDO/3 study of the formation, stability, and behavior of the various dihydropyridine isomers and re-lated compounds was carried out. The order of stability of the seven dihydro isomers is as follows: 1, 4> 3, 4> 1, 2> 2, 5> 2, 3» thetwo bicyclo structures. Protonation of the dihydropyridines occurs yielding preferentially enamine salts. The calculations of all these processes are in good agreement with experimental observations. The relative stabilitiesof the 1, 4-vs. 1, 2-dihydropyridines were well reproduced both for pyridine and its 1-methyl derivative. It is shown that the favorable electronic, interactions (hyperconjugation, homoaromaticity) can indeed account for theincreased stability of the 1, 4-dihydro isomers. Excellent agreement between the calculated (adiabatic and vertical) and observed ionization potentials was obtained.Although dihydropyridines2 are of utmost importance in biological systems, particularly the NAD-NADH which is involved in biological oxidation-reduction, simple dihydropyridines have not been extensively studied due to their sus-ceptibility to oxidation and variousaddition reactions and because of the lack of convenient methods for their preparation.