scholarly journals Solvent Induced Circular Dichroism in Conformational Analysis: Bile Pigments

1981 ◽  
Vol 36 (6) ◽  
pp. 735-738 ◽  
Author(s):  
Harald Lehner ◽  
Corinna Krauss ◽  
Hugo Scheer
Keyword(s):  
Circular Dichroism ◽  
Conformational Analysis ◽  
The Other ◽  
Bile Pigments ◽  
Induced Circular Dichroism ◽  
Steric Strain ◽  
Order Of Magnitude ◽  
Circular Dichroïsm ◽  
Rotational Strengths ◽  
Related Compounds

Abstract The applicability of solvent induced circular dichroism (SICD) for the conformational analysis of bile pigments has been investigated. The S-(-)-ethyl lactate induced rotational strengths for octaethylbilindion (4) and its dihydroderivative 5 are remarkably high. Related compounds, e.g. the isomeric purpurines 1 and 2 and formyltripyrrinon 3 exhibit an optical activity which is smaller by more than one order of magnitude. 1-3 are essentially free from steric strain so that a flat arrangement of the chromophore is most likely. On the other hand the closed conformations of 4 and 5 experience considerable steric repulsion of their terminal rings, so that a helical topology is energetically favoured. This distinction is reflected in the magnitude of the SICD observed and demonstrates its applicability for the conformational analysis of bile pigments.

Optical Activity of Symmetric Compounds in Chiral Media. I. Induced Circular Dichroism of Unbound Substrates

1971 ◽  
Vol 49 (4) ◽  
pp. 624-631 ◽  
Author(s):  
L. D. Hayward ◽  
R. N. Totty
Keyword(s):  
Circular Dichroism ◽  
Carbonyl Compounds ◽  
Optical Rotation ◽  
Optically Active ◽  
Asymmetric Induction ◽  
Azo Compounds ◽  
Induced Circular Dichroism ◽  
Chiral Media ◽  
Circular Dichroïsm ◽  
Rotational Strengths

In the presence of chiral environment compounds, C, optical rotation is induced in symmetric substrates, S, and may be detected as circular dichroism in the electronic spectra of the solutions. Thus the n − π* transitions of symmetric and racemic carbonyl compounds, and of symmetric nitro and azo compounds, become optically active when these S are dissolved in chiral hydrocarbons, ketones, or carbinols, or in solutions of these C in achiral solvents. The rotational strengths of the induced circular dichroism bands of S are solvent, temperature, and concentration dependent. Only limited correlation of the sign and magnitude of the induced bands with the stereochemistry of C and S is evident on the data so far accumulated. Halogenated achiral solvents enhance the intensity, and, in some cases reverse the sign of the induced bands.A new mechanism of asymmetric induction is proposed in which specific bonding of C with S is not prerequisite.

Circular dichroism spectra of asymmetric unidentate amine complexes of cobalt(III)

1973 ◽  
Vol 26 (11) ◽  
pp. 2401 ◽  
Author(s):  
CJ Hawkins ◽  
GA Lawrance
Keyword(s):  
Circular Dichroism ◽  
Absorption Band ◽  
Aromatic Compounds ◽  
Visible Region ◽  
The Other ◽  
Circular Dichroism Spectra ◽  
Alkyl Derivatives ◽  
Cotton Effects ◽  
Circular Dichroïsm ◽  
Rotational Strengths

The preparations of pentaamminecobalt(III) complexes of a series of asymmetric unidentate amines are reported. The circular dichroism spectra for the (S)-amines show negative Cotton effects under the 1A1g → 1T1g absorption band, which are somewhat solvent dependent but independent of temperature down to -190�C. The vicinal effect from 1- cyclohexylethylamine was comparable to that from analogous aromatic compounds, but the simpler alkyl derivatives were found to impose smaller rotational strengths on the d-d transitions. The lack of measurable c.d. in the visible region for tetraammine((S)-butane-1,3- diamine)cobalt(III) is reported and discussed in the light of the other studies.

Enantiopure methoxetamine stereoisomers: chiral resolution, conformational analysis, UV-circular dichroism spectroscopy and electronic circular dichroism

2021 ◽  
Author(s):  
Kun Won Lee ◽  
Ahmed H. E. Hassan ◽  
Youngdo Jeong ◽  
Seolmin Yoon ◽  
Seung-Hwan Kim ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Conformational Analysis ◽  
Absolute Configuration ◽  
Circular Dichroism Spectroscopy ◽  
Chiral Resolution ◽  
Treatment Resistant Depression ◽  
Treatment Resistant ◽  
Electronic Circular Dichroism ◽  
Resistant Depression ◽  
Circular Dichroïsm

Enantioseparation and assignment of absolute configuration of methoxetamine (MXE) enantiopure stereoisomers; a promising novel antidepressant for management of treatment-resistant depression.

Conformational analysis of thymidylate synthase from amino acid sequence and circular dichroism

Biochemistry ◽  
1986 ◽  
Vol 25 (21) ◽  
pp. 6650-6655 ◽  
Author(s):  
Parthasarathy Manavalan ◽  
Denice M. Mittelstaedt ◽  
Michael I. Schimerlik ◽  
W. Curtis Johnson
Keyword(s):  
Circular Dichroism ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Conformational Analysis ◽  
Thymidylate Synthase ◽  
Circular Dichroïsm
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