Macrocyclic compounds functionalization

Poly (macrocyclic) compounds. The analytical application of compounds such as crown polyethers and cryptands is based on their ability to function as ligands and form stable stoichiometric complexes with certain cations. Special importance is due to their preference for alkali metal ions which do not form complexes with many other ligands. A number of these compounds are commercially available and their properties and analytical applications have been described by Cheng et a/.11... 

Macrocyclic compounds with ion-chelating properties occur naturally and often function as ionophores, translocating ions across biological membranes many of these compounds are small cyclic polypeptides. Some natural carboxylic polyethers are selective for Li+ and are, therefore, ionophores for Li+. Monensin, shown in Figure Id, is a natural ionophore for Na+ but it will also complex with Li+ and it has been shown to mediate the transport of Li+ across phospholipid bilayers [21]. It has been proposed that synthetic Li+-specific ionophores have a potential role as adjuvants in lithium therapy, the aim being to reduce the amount of... 

Gokel prepared a series of novel bis- and tris(macrocyclic) compounds, which have been designed as models for cation-conducting channels that function in... 

The theonezolides A-C (431-433) were isolated from the sponge Theonella sp. They are 37-membered macrocyclic compounds consisting of two principal fatty acid chains with various functionalities such as a sulfate ester, an oxazole, and a thiazole [336, 337]. Compounds 431-433 displayed cytotoxic activity against L1210 and KB cells and were found to have a unique bioactivity in terms of induction of rabbit platelet shape change and aggregation [338]. 

Lithium forms a very wide range of complexes34 with amines, ethers, carboxyl-ates, alkoxides, dialkylamides, and many other ligands whose structures are usually quite different from those of the other M+ ions. Some of these are shown schematically in 3-IV. However, we may note that in many of these compounds lithium can have coordination numbers 3-7. Some ionophores with high preference for Li+ are crown ethers with long aliphatic chains and other macrocycles with functional groups may have utility for therapy in brain disorders for which Li+ salts are used. 

Cz+diimine macrocycle compounds are formed by template condensations of an a-diketone (usually 2,3-butanedione or benzil), 2 + 2 with diamines, e.g., (34), or 1 +1 with tetraamines, e.g., (35) (Scheme 10). The resulting flat macrocycle cations form many stacked compounds, often with flat metal ion-containing anions, which exhibit spin coupling. The imine groups for the Ni11 compounds are reduced with NaBH4 and one of each cz+diimine function for the Co111 compounds by hypophosphorous acid.44... 

Figure 2.5.11 Di-, tri-, tetra- and hexanuclear macrocycles can be prepared from carboxylate-derived connectors using (a) dicarboxylates (b) functionalized monocarboxylates and (c) organotin compounds functionalized with a carboxyl ate group...

Syntheses of macrocyclic compounds, particularly heterophanes and crowns, by utilizing metal complexation, their structure, and function 02YGK184. 

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