Synthesis of novel expanded calixphyrins:: Anion binding properties of a calix[6]phyrin with a deep cavity
Synthesis of novel expanded calixphyrins:: Anion binding properties of a calix[6]phyrin with a deep cavity
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DOI：
10.1021/ja005842c
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发表时间：
2001-03-07
影响因子：
15
通讯作者：
Sessler, JL
中科院分区：
文献类型：
--
作者：
Bucher, C;Zimmerman, RS;Sessler, JL
卟啉和杯吡咯的化学杂化物杯-[n]杯吡咯是含有至少一个sp3杂化介孔样桥接碳原子的多吡咯大环。虽然杯状[n]卟啉衍生物的例子有很多，如经典结构的邻苯啉、1异卟啉、2,5,10 -或5,15 -二氢卟啉、3和卟烯，4，但高阶杯状[n]卟啉（n> - 4）的化学性质实际上尚未被探索。最近，我们报道了杯状[6]和杯状[9]卟啉的合成，这两个大环含有一系列共轭二吡罗甲烷亚基，通过sp3杂化介孔样桥接碳原子连接。我们现在已经发现，通过使用适当的无环多吡啶前体，可以改变高阶杯[n]卟啉中氧化与非氧化类中介孔碳原子的比例，以及这些桥接中心在大环骨架内的分布。具体来说，我们报道了从5,5,10,10 -四甲基三吡喃2中合成5,5,5 - 10,10 - 20,20 - 25,25 -八甲基杯[6]卟啉1，并表明这种非平面物质在溶液和固体中都可以作为阴离子受体。三吡喃2的合成如方案1所示。它是由TFA酸催化吡咯和丙酮缩合得到的。最佳条件是在室温下搅拌2小时，然后加入三乙胺。通过蒸馏去除多余的吡咯，然后进行柱层析纯化（硅胶；己烷-二氯甲烷洗脱液），以大约5%的收率产生2，以及大量已知的二吡咯甲烷3（约25%）
Chemical hybrids of the porphyrins and calixpyrroles, calix-[n] phyrins, are polypyrrolic macrocycles that contain at least one sp3 hybridized meso-like bridging carbon atom. While examples of calix [4] phyrin derivatives, represented by such classic structures as the phlorins, 1 isoporphyrins, 2 5, 10-or 5, 15-dihydroporphyrins, 3 and porphomethenes, 4 abound, the chemistry of higher order calix-[n] phyrins (n> 4) remains virtually unexplored. 3f, 5 Recently, we reported the synthesis of calix [6]-and calix [9] phyrin, macrocycles that contain a succession of conjugated dipyrromethene subunits linked via sp3 hybridized meso-like bridging carbon atoms. 3f We have now found that, by using appropriate acyclic polypyrrolic precursors, it is possible to modify the ratio of oxidized to nonoxidized meso-like carbon atoms in higher order calix [n] phyrins as well as the distribution of these bridging centers within the macrocyclic skeleton. Specifically, we report here the synthesis of 5, 5-10, 10-20, 20-25, 25-octamethylcalix [6] phyrin 1, obtained from 5, 5, 10, 10-tetramethyltripyrrane 2, and show that this nonplanar species acts as an anion receptor both in solution and in the solid sate.The synthesis of tripyrrane 2 is shown in Scheme 1. 6 It is obtained from the TFA acid-catalyzed condensation of pyrrole and acetone. Optimal conditions involved stirring at room temperature for 2 h followed by the addition of triethylamine. Removal of excess pyrrole by distillation followed by column chromatographic purification (silica gel; hexane-dichloromethane eluent) yielded 2 in an approximate yield of 5%, along with substantial quantities of the known dipyrromethane 3 (ca. 25%