Design, Synthetize And Properties Of Inherently Chiral Biscalixarene

Biscalixarene is formed by two calixarene units through the connected bridginggroup, compared with the single calixarene studied more popular, its structure is morecomplex, and its properties may be more colorful and rich which the single calixarenedo not have, so it has great background to synthesis biscalixarene with novel structureand unique properties, they will play an important role and build immeasurableapplication prospects in the aspects such as molecular recognition, molecularassembly, bio-simulation, optoelectronic materials, functional calixarene aggregatesand so on. This paper designed two kinds of novel inherently chiral biscalixarene andsmoothly realized the chiral resolution of racemic final product using differentmethods, and make a further study of the chiral recognition ability of an inherentlychiral biscalix[4]arene cone-partial cone conformer through1H-NMR spectroscopyexperiments. This article consists of two parts, the first part introduce chemicalresolution and chiral recognition of an inherently chiral biscalix[4]arene cone-partialcone conformer, and the second section describes the synthesis and resolution of aninherent chiral biscalix[4,5]arene.Part â… : Chemical resolution and chiral recognition of an inherently chiralbiscalix[4]arene cone-partial cone conformerWe assemble two calix[4]arene components in a1,3-position linking with1,2-position pattern by two triglycol bridge fragment at the narrow rims to form abiscalix[4]arene precursor with only one plane of symmetry, then desymmetrizationby further modification afforded an inherently chiral biscalix[4]arene cone-partialcone conformer as racemates. The structure of the products and intermediates wasconfirmed through1H-NMR,13C-NMR, MS, elemental analysis, and its opticalresolution have also been realized through the chiral auxiliary reagent (S)-Binol, thepartial cone calix[4]arene component plays a crucial role in optical resolution. Inaddition, we also make a further study of the chiral recognition ability of the targetcompounds to chiral amino alcohols. Study found that these target compounds can beselective discerned with chiral amino alcohols, among these chiral amino alcohol, the target compound distinctly interact enantiodiscriminantly with2-phenylglycinol.This indicates that the target compound can be used as chiral recognition reagents todiscern parts of the amino alcohol. And to some extent it can be used as the chiralNMR identification reagent to determine the optical purity of the phenylglycinolcompound.Part â…¡: Synthetize and resolution of an inherently chiral biscalix[4,5]areneThe covalent assembly of two or more calixarene sub-units is a useful approach totailor multicavity supramolecular receptors displaying intriguing geometries andmolecular recognition abilities, that are absent in the single-cavity molecularframeworks of their precursors. In view of the complexity and diversity of thisbiscalixarene structure and its superiority performance, we assemble a calix[4]arenecomponents and a calix[5]arene components in a1,3-position linking with1,2-position pattern by two triglycol bridge fragment at the narrow rims to form abiscalix[4,5]arene precursor with only one plane of symmetry, then desymmetrizationby further modification afforded a series of inherently chiral biscalix[4,5]arene asracemates. The structure of the products and intermediates was confirmed through1H-NMR,13C-NMR, MS, elemental analysis, and its optical resolution was failed toachieve by chemical methods, and finally we successful realized its optical resolutionthrough chiral HPLC. The performance of the inherently chiral biscalix[4,5]arene tobe explored in further study.