Design and selection of host molecules in the resolution by inclusion compound formation. Molecular recognition by Troeger's base and its derivatives.
Item
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Title
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Design and selection of host molecules in the resolution by inclusion compound formation. Molecular recognition by Troeger's base and its derivatives.
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Identifier
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AAI9304722
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identifier
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9304722
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Creator
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Qi, Jian Zhong.
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Contributor
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Mentor: Samuel H. Wilen
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Date
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1992
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Organic | Chemistry, Pharmaceutical
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Abstract
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Troger's base, 79(TB), has been resolved by diastereomeric salt formation with a strongly acidic resolving agent, 81. The resolution is attended by an asymmetric transformation. Enantiopure TB acts as a chiral solvating agent (CSA) in {dollar}\sp1{dollar}H NMR toward several secondary and tertiary alcohols. The configuration of TB has been determined by X-ray crystallography on salt 82a to be (+)-(5S, 11S) which is contrary to that previously established from the circular dichroism spectrum by the method of exciton chirality.;Enantiopure (+)-TB methosulfate 107a formed in situ resolves eight out of nine selected alcohols by clathrate formation. The enantiomeric excess (ee) observed is 10-80%. In contrast, enantiopure TB does not act as a host toward racemic alcohols in resolution by inclusion compound formation.;Compound 107a formed in situ acts as CSA toward all alcohols (nine) tested. Anisochrony is observed clearly by {dollar}\sp1{dollar}H NMR in aliphatic alcohols, 2-butanol (92) and 4-octanol (93).;The chemical shift difference ({dollar}\Delta\delta{dollar}) between two sets of splitting peaks is larger in 107a as CSA than in 79. Inclusion phenomena have also been observed with 82a and 114 serving as hosts.;Hydrogen bonding, aryl-aryl interaction, the ionization (onium salt formation), the size of the host lattice void, the rigid skeleta and the molecular symmetry of the host are all considered as potential contributors to the molecular recognition leading to inclusion compound formation.;Hydrogen bonds play an important role in resolution by inclusion compound formation. However, a balance of all binding forces controls the results of resolution by inclusion compound formation.;Host compounds with more O, and N atoms functional groups; rigid geometry; benzene rings and triple bonds seem favorable for inclusion compound formation and molecular recognition. Compound 107a is considered to have a majority of these beneficial features.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
