Optical Rotatory Dispersion Studies. XCIX.1Superposed Multiple Cotton Effects of Saturated Ketones and Their Significance in the Circular Dichroism Measurement of (-)-Menthone2

1965 ◽  
Vol 87 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Keith M. Wellman ◽  
P.H.A. Laur ◽  
W.S. Briggs ◽  
Albert Moscowitz ◽  
Carl Djerassi
Keyword(s):  
Circular Dichroism ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Circular Dichroism Measurement ◽  
Cotton Effects ◽  
Circular Dichroïsm

Optical Rotatory Dispersion and Circular Dichroism Studies on Ocular Lens Proteins

1971 ◽  
Vol 49 (4) ◽  
pp. 426-430 ◽  
Author(s):  
Howard A. Jones ◽  
Sidney Lerman
Keyword(s):  
Circular Dichroism ◽  
Electronic Absorption Spectra ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Helical Conformation ◽  
Optical Rotatory ◽  
Ocular Lens ◽  
Cotton Effects ◽  
Beta Structure ◽  
Circular Dichroïsm

A study has been made of the circular birefringence and circular dichroism of alpha and gamma crystallins obtained from dogfish lenses. The Cotton effects in the optical rotatory dispersion and circular dichroism spectra are correlated with maxima in the electronic absorption spectra. On the basis largely of this correlation, the transitions which give rise to the Cotton effects have been assigned to various chromophores. It is concluded that the secondary structure of these proteins is made up of beta structure and the unordered conformation. Little or no α-helical conformation seems to be present.

Carboxyl and aromatic chromophores: optical rotatory dispersion and circular dichroism studies

1967 ◽  
Vol 297 (1448) ◽  
pp. 66-78 ◽  
Keyword(s):  
Circular Dichroism ◽  
Theoretical Background ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Open Chain ◽  
Structural Problems ◽  
Rigid Conformation ◽  
Extensive Collection ◽  
Circular Dichroïsm

Until recently the carbonyl chromophore has been of prime importance in the appli­cation of optical rotatory dispersion (o. r. d.) and circular dichroism (c. d.) to organic structural problems (Djerassi 1960; Crabbé 1965). The reasons were, first, the accessibility of the n → π * band of the carbonyl group at 290 nm to the first com­mercial spectropolarimeters; secondly, the availability of many carbonyl com­pounds of known stereochemistry, on which Djerassi and subsequently others worked so intensively; and, thirdly, a few years later the development of the octant rule as a theoretical background to the extensive collection of experimental data which had then been made by Djerassi (Moffitt et al . 1961). In this treatment we might say that one looks at the asymmetry of the molecule through the ‘eyes’ of the relevant chromophore; in less anthropomorphic terms, one considers the symmetry planes of the orbitals involved in the 290 nm transition as a frame of reference. It is appropriate to consider the logical order in which the octant rule was applied to carbonyl compounds of increasing flexibility. Djerassi had very wisely started with ketones of rigid conformation, trans -decalones (e. g. I) and their polycyclic ana­logues; the work then passed to more flexible compounds such as the cis -decalones (II), the monocyclic ketones (III) and then finally to open-chain ketones, including steroid side-chain ketones (e. g. IV); with these latter flexible compounds, the o. r. d. method is a valuable probe for conformational studies (Crabbé 1965, pp. 134-43). The c. d. treatment was applied initially by the Roussel-Uclaf group in Paris to similar series of ketones (Velluz, Legrand & Grosjean 1965).

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