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.

Partial methylation of methyl 2,6-dideoxy-α-D-xylo- and α-D-lyxo-hexopyranoside

1981 ◽  
Vol 46 (10) ◽  
pp. 2410-2420 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek
Keyword(s):  
Sodium Hydroxide ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Relative Rate ◽  
Reaction Rates ◽  
Steric Effects ◽  
Side Reactions ◽  
Hydroxyl Groups ◽  
Partial Methylation ◽  
Relative Rate Constants

Rate of methylation of the hydroxyl groups in the title glycosides was investigated during their reaction with methyl iodide and sodium hydroxide in acetonitrile. Relative rate constants of the side-reactions and subsequent reactions taking place were calculated. The differences in the reaction rates of methylation of individual hydroxyl groups are discussed in connection with the possible polar and steric effects.

Partial methylation of methyl α-D- and β-D-threofuranoside

1990 ◽  
Vol 55 (7) ◽  
pp. 1777-1782 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek ◽  
Ivan Raich
Keyword(s):  
Sodium Hydroxide ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Relative Rate ◽  
Hydroxyl Groups ◽  
Partial Methylation ◽  
Methylation Rate ◽  
Consecutive Reactions ◽  
Relative Rate Constants ◽  
The Individual

The methylation rate of hydroxyl groups of the title glycosides I and II has been studied in their reaction with methyl iodide and sodium hydroxide in acetonitrile. From the relative rate constants determined for the side and consecutive reactions taking place the differences in methylation rate of the individual hydroxyl groups have been deduced and are discussed from the standpoint of possible steric and polar effects.

scholarly journals Strong intramolecular hydrogen bonds and steric effects involving C═S groups: An NMR and computational study

2019 ◽  
Vol 58 (2) ◽  
pp. 154-162
Author(s):  
Rita S. Elias ◽  
Bahjat A. Saeed ◽  
Fadhil S. Kamounah ◽  
Fritz Duus ◽  
Poul Erik Hansen
Keyword(s):  
Hydrogen Bonds ◽  
Computational Study ◽  
Steric Effects ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

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.

Selective Accessibilities of Hydroxyl Groups in the Microstructure of Cotton Cellulose

1969 ◽  
Vol 39 (6) ◽  
pp. 530-542 ◽  
Author(s):  
S. P. Rowland ◽  
E. J. Roberts ◽  
C. P. Wade
Keyword(s):  
Sodium Hydroxide ◽  
Rate Constants ◽  
Relative Rate ◽  
Heterogeneous Systems ◽  
Heterogeneous Reactions ◽  
Cotton Cellulose ◽  
Hydroxyl Groups ◽  
Relative Rate Constants ◽  
The Individual ◽  
Liquid Chromatographic

The reactions of 2-chloroethyldiethylamine with the hydroxyl groups at C-2, C-3, and C-6 of the d-glucopyranosyl unit of cotton cellulose were investigated as a means of evaluating the relative accessibilities of these hydroxyl groups in heterogeneous reactions of fibrous cellulose. The relative rate constants for reactions of the individual types of hydroxyl groups were determined from reactions of cellulose in solution and from reactions of disordered cellulose in heterogeneous systems. Quantitative determinations of the distributions of 2-(diethylamino)ethyl substituents in the mono-substituted d-glucopyranosyl units involved hydrolysis of the chemically modified cellulose to glucose and substituted glucoses followed by gas-liquid chromatographic analysis. The relative accessibilities of the hydroxyl groups at C-2 and C-3 vs those at C-6 were estimated for crystalline celluloses by employing the relative rate constants (noted above) together with the experimentally measured distributions of substituents resulting from heterogeneous reactions of crystalline celluloses and appropriate kinetic expressions. The relative accessibilities of the hydroxyl groups at C-2, C-3, and C-6 in cellulose in strong mercerizing media approach those of cellulose in solution. In media of lower concentration of sodium hydroxide (i.e., 4 N or 13.9%), selective accessibilities of the individual types of hydroxyl groups become evident, and these selective accessibilities become pronounced in sodium hydroxide solutions of still lower concentrations (e.g., N and 2 N).

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
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