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Investigations of New Biomimetic Transamination Systems and Inclusion Complexation with Cyclodextrins.

Hjelmencrantz, Anders LU (2000)
Abstract (Swedish)
Popular Abstract in Swedish

Avhandlingen behandlar ett syntetiskt system för en process som liknar den kroppsegna processen för metabolism av aminosyror (transaminering).



Avhandlingen behandlar också de fundamentala krafter som ligger bakom inbindningen av olika substrat i enzym. Även detta är studerat genom starkt förenklade modellsystem, bestående av cykliska strukturer uppbyggda av glukosenheter, sk. cyklodextriner.
Abstract
Two new transamination systems are described. The first example is a dibenzo[a,d]- cycloheptene containing system, designed to accomplish a [1,3]-hydride transfer. Several catalysts have been examined for this purpose. tris-Pentafluorophenyl borane was found to be the most efficient catalyst. The stereochemistry of several closely related dibenzo[a,d]- cycloheptene have also been examined, displaying a solvent dependent in the preferred conformation.



The second transamination system consists of a thioxanthene dioxide moiety, to afford facile [1,3]-proton transfer. Several imines of a-keto esters were synthesised, to result in imines of a-amino esters upon rearrangement in 75%-quantitative yields. Simple amines, amidines... (More)
Two new transamination systems are described. The first example is a dibenzo[a,d]- cycloheptene containing system, designed to accomplish a [1,3]-hydride transfer. Several catalysts have been examined for this purpose. tris-Pentafluorophenyl borane was found to be the most efficient catalyst. The stereochemistry of several closely related dibenzo[a,d]- cycloheptene have also been examined, displaying a solvent dependent in the preferred conformation.



The second transamination system consists of a thioxanthene dioxide moiety, to afford facile [1,3]-proton transfer. Several imines of a-keto esters were synthesised, to result in imines of a-amino esters upon rearrangement in 75%-quantitative yields. Simple amines, amidines and guanidines were examined with respect to their catalytic activity in the transamination reaction. DBU, benzamidine, and a pseudo-C2-symmetric guanidine proved to be successful catalysts. Asymmetric induction was also evaluated with the pseudo-C2- symmetric guanidine, in a maximum asymmetric induction of 45% e.e.



The unusually high dynamic stability of the 1:2 complex between 1,4-dimethylbicyclo- octane and a-cyclodextrin has been studied by various NMR methods combined with computa- tional methods. Hydrophobicity of the guest molecule together with a highly preorganised structure of the guest and the host molecules are suggested as main origines for the observed high dynamic stability. (Less)
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author
opponent
  • Prof Baltzer, Lars
organization
publishing date
type
Thesis
publication status
published
subject
keywords
stereochemis, bicyclooctanes.Transamination, complexation, cyclodextrins, proton transfer, hydride transfer, stereochemistry, Transamination, Organic chemistry, Organisk kemi
pages
48 pages
publisher
Organic Chemistry, Lund University
defense location
sal F (KC)
defense date
2000-12-08 13:15
external identifiers
  • Other:ISRN: LUNDL/NKOK-1043-SEISRN LUNDL/NKOK-1043-SE
ISBN
91-7874-102-5
language
English
LU publication?
yes
id
9cf7692e-6d9e-4c90-9710-270aea5642d5 (old id 41067)
date added to LUP
2007-08-01 09:10:56
date last changed
2016-09-19 08:45:02
@misc{9cf7692e-6d9e-4c90-9710-270aea5642d5,
  abstract     = {Two new transamination systems are described. The first example is a dibenzo[a,d]- cycloheptene containing system, designed to accomplish a [1,3]-hydride transfer. Several catalysts have been examined for this purpose. tris-Pentafluorophenyl borane was found to be the most efficient catalyst. The stereochemistry of several closely related dibenzo[a,d]- cycloheptene have also been examined, displaying a solvent dependent in the preferred conformation.<br/><br>
<br/><br>
The second transamination system consists of a thioxanthene dioxide moiety, to afford facile [1,3]-proton transfer. Several imines of a-keto esters were synthesised, to result in imines of a-amino esters upon rearrangement in 75%-quantitative yields. Simple amines, amidines and guanidines were examined with respect to their catalytic activity in the transamination reaction. DBU, benzamidine, and a pseudo-C2-symmetric guanidine proved to be successful catalysts. Asymmetric induction was also evaluated with the pseudo-C2- symmetric guanidine, in a maximum asymmetric induction of 45% e.e.<br/><br>
<br/><br>
The unusually high dynamic stability of the 1:2 complex between 1,4-dimethylbicyclo- octane and a-cyclodextrin has been studied by various NMR methods combined with computa- tional methods. Hydrophobicity of the guest molecule together with a highly preorganised structure of the guest and the host molecules are suggested as main origines for the observed high dynamic stability.},
  author       = {Hjelmencrantz, Anders},
  isbn         = {91-7874-102-5},
  keyword      = {stereochemis,bicyclooctanes.Transamination,complexation,cyclodextrins,proton transfer,hydride transfer,stereochemistry,Transamination,Organic chemistry,Organisk kemi},
  language     = {eng},
  pages        = {48},
  publisher    = {ARRAY(0x7e09528)},
  title        = {Investigations of New Biomimetic Transamination Systems and Inclusion Complexation with Cyclodextrins.},
  year         = {2000},
}