scholarly journals Progress and Achievements in Glycosylation of Flavonoids

2021 ◽  
Vol 9 ◽  
Author(s):  
Ruslana S. Khodzhaieva ◽  
Eugene S. Gladkov ◽  
Alexander Kyrychenko ◽  
Alexander D. Roshal
Keyword(s):  
Hydrogen Bonds ◽  
Hydroxyl Groups ◽  
General Strategy ◽  
Reaction Conditions ◽  
Parent Molecule ◽  
Intramolecular Hydrogen Bonds ◽  
Steric Factors ◽  
Glycosyl Donor ◽  
Intramolecular Hydrogen ◽  
Donor Moiety

In recent years, the chemistry of flavonoid glycosylation has undergone significant developments. This mini-review is devoted to summarizing existing strategies and methods for glycosylation of natural and synthetic flavonoids. Herein we overviewed the reaction conditions of flavonoid glycosylation depending on the position of hydroxyl groups in a parent molecule, the degree of it conjugation with the π-system, the presence of steric factors, the formation of intramolecular hydrogen bonds, etc. Especial attention was given to the choice of the glycosyl donor moiety, which has a significant effect on the yield of the final glycosidated products. Finally, a general strategy for regioselective glycosylation of flavonoids containing several hydroxyl groups is outlined.

The conformation of substituted hydroxyureas and hydroxythioureas in solution

1979 ◽  
Vol 44 (3) ◽  
pp. 895-907 ◽  
Author(s):  
Jiří Mollin ◽  
Pavel Fiedler ◽  
Václav Jehlička ◽  
Otto Exner
Keyword(s):  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Dipole Moments ◽  
Intramolecular Hydrogen Bonds ◽  
Nonpolar Solvents ◽  
Steric Factors ◽  
Intramolecular Hydrogen ◽  
Hydroxyl Hydrogen

The conformation of 1,3-disubstituted 1-hydroxyureas Ia-d and 1-hydroxythioureas IIa-d, mostly with aromatic substituents, was investigated by means of dipole moments in dioxan solution and by infrared spectroscopy. The results are concordant for the two classes of compounds. The most populated conformation is near to the planar Z, E, ap form (A), or possibly with the hydroxyl hydrogen out of the N-C-N-O plane (between A and B). This finding from the analysis of dipole moments is corroborated by the presence of the amide-II band and absence of intramolecular hydrogen bonds. While the conformation of hydroxyureas seems to be virtually uniform, in the case of hydroxythioureas a less abundant rotamer may be present in nonpolar solvents, possibly the E, E, sp (G) or E, E, ap (F) form. The conformation found (A) is not explicable in terms of hydrogen bonds and/or steric factors when compared to symmetrically substituted ureas (thioureas) and to N-alkylhydroxamic acids.

Reactivity of hydroxyl groups of 1,6 : 2,3- and 1,6 : 3,4-dianhydrido-β-D-hexapyranoses in methylation with iodomethane

1988 ◽  
Vol 53 (3) ◽  
pp. 633-637 ◽  
Author(s):  
Stanislav Sámek ◽  
Tomáš Trnka ◽  
Miloslav Černý
Keyword(s):  
Hydrogen Bonds ◽  
Rate Constants ◽  
Silver Oxide ◽  
Relative Rate ◽  
Steric Effects ◽  
Hydroxyl Groups ◽  
Intramolecular Hydrogen Bonds ◽  
Relative Rate Constants ◽  
Intramolecular Hydrogen

Relative rate constants for reaction of 1,6 : 2,3- and 1,6 : 3,4-dianhydro-β-D-hexapyranoses with iodomethane in acetonitrile in the presence of silver oxide were measured. Their values, ranging from 1 to 8.6 were interpreted on the basis of polar and steric effects and intramolecular hydrogen bonds.

IR spectra of methyltetrosides and their monomethyl ethers in the region of valence vibration of hydroxyl groups

1981 ◽  
Vol 46 (13) ◽  
pp. 3289-3293 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Valence Vibration ◽  
Hydroxyl Groups ◽  
Spectral Absorption ◽  
Absorption Bands ◽  
Intramolecular Hydrogen Bonds ◽  
Individual Bands ◽  
Intramolecular Hydrogen

IR Spectral absorption bands ν(OH) (3 700 to 3 400 cm-1) of the both anomers of methyl D-threofuranoside, methyl-D-erythrofuranoside, and their monomethyl ethers have been studied in dilute tetrachloromethane solution. For these 11 compounds positions and intensities of individual bands are discussed with respect to possible formation of intramolecular hydrogen bonds.

Controlling emissive properties by intramolecular hydrogen bonds: alkyl and aryl meso‐substituted porphycenes

2021 ◽  
Author(s):  
Jacek Waluk ◽  
Arkadiusz Listkowski ◽  
Natalia Masiera ◽  
Michał Kijak ◽  
Roman Luboradzki ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

Energies of intramolecular hydrogen bonds in some alcohols

1974 ◽  
Vol 20 (3) ◽  
pp. 414-415
Author(s):  
Ya. A. Shuster ◽  
V. A. Granzhan ◽  
P. M. Zaitsev
Keyword(s):  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

Hydrogen bonds in derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea

1991 ◽  
Vol 56 (4) ◽  
pp. 880-885 ◽  
Author(s):  
Oľga Hritzová ◽  
Dušan Koščík
Keyword(s):  
Hydrogen Bonds ◽  
Spectral Studies ◽  
Intramolecular Hydrogen Bonds ◽  
Tautomeric Forms ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Intramolecular hydrogen bonds of the N-H···O=C type have been detected in the derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea on the basis of IR spectral studies. The title compounds can exist in two tautomeric forms.

Spin-spin coupling via intramolecular hydrogen bonds

1985 ◽  
Vol 25 (5) ◽  
pp. 808-810
Author(s):  
L. N. Kurkovskaya ◽  
Yu. M. Chunaev ◽  
N. M. Przhiyalgovskaya
Keyword(s):  
Hydrogen Bonds ◽  
Spin Coupling ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Spin Spin Coupling

3,3′-N,N′-Bis(amino)-2,2′-bipyridine — An unusually methylation-resistant amine

2011 ◽  
Vol 89 (8) ◽  
pp. 971-977
Author(s):  
Danielle M. Chisholm ◽  
Robert McDonald ◽  
J. Scott McIndoe
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Complex Mixtures ◽  
Amino Groups ◽  
Intramolecular Hydrogen Bonds ◽  
X Ray ◽  
Intramolecular Hydrogen

Methylation of aromatic amino groups is usually straightforward, but the formation of two intramolecular hydrogen bonds in 3,3′-N,N′-bis(amino)-2,2′-bipyridine and (or) the potential for ring methylation prevents the clean tetramethylation of this molecule. Numerous attempts to make 3,3′-N,N′-bis(dimethylamino)-2,2′-bipyridine produced only complex mixtures of variously methylated products, and the only isolated molecule was 3,3′-N,N′-bis(methylamino)-2,2′-bipyridine, for which an X-ray crystal structure was obtained.

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