Chiroptical properties of monosaccharide acetyl derivatives

1985 ◽  
Vol 50 (3) ◽  
pp. 683-689
Author(s):  
Slavomír Bystrický ◽  
Tibor Sticzay ◽  
Štefan Kučár ◽  
Eva Petráková ◽  
Rudolf Toman
Keyword(s):  
Circular Dichroism ◽  
Dipole Moments ◽  
Spatial Arrangement ◽  
Positional Isomers ◽  
Optical Rotatory ◽  
Chiroptical Properties ◽  
Rotational Strength ◽  
Circular Dichroïsm ◽  
Optical Rotatory Strength

Circular dichroism of positional isomers of acetylated methyl β-D-xylopyranosides, 1,6-anhydro-β-D-glucopyranoses and methyl α-L-rhamnopyranosides is discussed considering the mechanism of optical rotatory strength nature. Interactions determining the signs are influenced by the character of the solvent. Magnitude of the effect depends on the spatial arrangement of the chromophore environment. This effect is lowered with diacetyl derivatives, where the interaction of transitional dipole moments of acetyl groups is the main source of optical rotational strength.

Study of D-glyceraldehyde by circular dichroism and ultraviolet spectroscopy

1981 ◽  
Vol 46 (1) ◽  
pp. 240-245 ◽  
Author(s):  
Slavomír Bystrický ◽  
Tibor Sticzay ◽  
Mária Poláková ◽  
Michal Fedoroňko
Keyword(s):  
Circular Dichroism ◽  
Quantum Chemical ◽  
Conformational Equilibrium ◽  
Uv Spectroscopy ◽  
Spatial Arrangement ◽  
Chemical Calculation ◽  
Rotational Strength ◽  
Circular Dichroïsm ◽  
Oligomeric Forms ◽  
Circular Dichroic

The behaviour of D-glyceraldehyde in water, dimethyl sulfoxide, their mixtures and in 1,1,1,3,3,3-hexafluoro-2-propanol was studied by circular dichroism and UV spectroscopy in the 20-80°C temperature range. Fresh-prepared solutions of D-glyceraldehyde exist in a substantial measure in dimeric or oligomeric forms, which passed to a monomeric one. The different character of interaction of solvents with monomeric D-glyceraldehyde is discussed. The bisignate circular dichroic curves are associated with conformational equilibrium of rotamers. The presumption on their spatial arrangement is confronted with the quantum chemical calculation of the rotational strength.

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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