Regio- and stereoisomeric control of the aggregation of zinc-chlorins possessing inverted interactive hydroxyl and carbonyl groups.
Regio- and stereoisomeric control of the aggregation of zinc-chlorins possessing inverted interactive hydroxyl and carbonyl groups.
复制标题
具有反向相互作用的羟基和羰基的锌-二氢卟酚聚集的区域和立体异构控制。
DOI：
10.1021/jo010484x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
H. Tamiaki
中科院分区：
文献类型：
--
作者：
S. Yagai;Tomohiro Miyatake;H. Tamiaki
作为具有3（1）-仲醇羟基和13（1）-氧代基团的自聚集的天然存在的镁-二氢卟酚细菌叶绿素-d的模型，合成了具有3（1）-氧代和13（1）-仲羟基（1）或叔羟基（2）的锌-二氢卟酚。与四氢呋喃溶液中的单体相比，非对映异构体13（1）R-1 R和13（1）S-1 S在1 v/v% CH（2）Cl（2）-己烷溶液中产生红移的最大吸收（1 R中643 -> 674 nm，1 S中708 nm），表明它们自聚集。因此，在N21-N23分子（Q（y））轴上的3（1）/13（1）或13（1）/3（1）处的两个基团的定位对于自聚集未必重要。（1）H NMR和CD光谱研究表明，1 R在674 nm处的吸收物种是一个面对面的“封闭”二聚体，而1 S在708 nm处的吸收物种是一个由头尾相连的“开放”二聚体聚集而成的大的寡聚体。这种对1 R和1 S聚集的非对映体控制比在区域异构的3（1）-仲醇R/S-非对映体3R和3S中观察到的更明显。这一差异归因于1中外五元环的13（1）-羟基的构象固定。与自聚集的3（1）-叔醇4相反，13（1）-叔醇2的两个13（1）-差向异构体即使在非极性有机介质中也是单体的：额外的13（1）-甲基（1 -> 2）由于甲基在分子间π-π相互作用中的干扰而显著抑制自聚集。
As models for a self-aggregative, naturally occurring magnesium-chlorin bacteriochlorophyll-d possessing 3(1)-secondary alcoholic hydroxyl and 13(1)-oxo groups, zinc-chlorins were synthesized with 3(1)-oxo and 13(1)-secondary (1) or tertiary hydroxyl groups (2). Compared to the monomers in a tetrahydrofuran solution, diastereomers 13(1)R-1R and 13(1)S-1S gave red-shifted absorption maxima (643 --> 674 nm in 1R and 708 nm in 1S) in 1 v/v% CH(2)Cl(2)-hexane solution, indicating their self-aggregation. Therefore, the positioning of the two groups at 3(1)/13(1) or 13(1)/3(1) on the N21-N23 molecular (Q(y)) axis is not necessarily important for the self-aggregation. The (1)H NMR and CD spectroscopic studies showed that the 674 nm absorbing species of 1R was characterized as a face-to-face "closed" dimer, while the 708 nm absorbing species of 1S was a large oligomer constructed with aggregation of head-to-tail "open" dimers. This diastereomeric control over the aggregation of 1R and 1S is more pronounced than that observed in the regioisomerically 3(1)-secondary alcoholic R/S-diastereomers 3R and 3S. The difference is ascribable to the conformational fixation of the 13(1)-hydroxyl group of the exo five-membered ring in 1. In contrast to self-aggregative 3(1)-tertiary alcoholic 4, both 13(1)-epimers of 13(1)-tertiary alcoholic 2 were monomeric even in nonpolar organic media: the additional 13(1)-methyl group (1 --> 2) drastically suppressed the self-aggregation due to the interference of the methyl group in intermolecular pi-pi interaction.