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.

scholarly journals A novel сalcium trifluoroacetate structure

2021 ◽  
Vol 16 (4) ◽  
pp. 352-362
Author(s):  
A. A. Vasilyeva ◽  
T. Yu. Glazunova ◽  
D. S. Tereshchenko ◽  
E. Kh. Lermontova
Keyword(s):  
Thermal Decomposition ◽  
Hydrogen Bonds ◽  
Trifluoroacetic Acid ◽  
Calcium Fluoride ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Intramolecular Hydrogen Bonds ◽  
X Ray ◽  
Cell Parameters ◽  
Intramolecular Hydrogen

Objectives. The study was devoted to considering the features of the synthesis and crystal structure of calcium trifluoroacetate Ca2(CF3COO)4·8CF3COOH and investigating the products of its thermal behavior.Methods. The compositions of the proposed structural form were characterized by various physicochemical methods (X-ray diffraction, IR spectroscopy), and the products of thermal decomposition were determined under dynamic vacuum conditions.Results. The reaction between calcium carbonate and 99% trifluoroacetic acid yielded a new structural type of calcium trifluoroacetate Ca2(CF3COO)4·8CF3COOH (I) in the form of colorless prismatic crystals unstable air. X-ray diffraction results confirmed the composition I: space group P21, with unit cell parameters: a = 10.0193(5) Å, b = 15.2612(7) Å, c = 16.3342(8) Å, β = 106.106(2)°, V = 2399.6(2) Å3, Z = 2. The structure is molecular, constructed from Ca2(CF3COO)4·8CF3COOH dimers. The end molecules of the trifluoroacetic acid were involved in the formation of intramolecular hydrogen bonds with oxygen atoms of the bidentate bridging anions CF3COO−. There were strongly pronouncedsymmetric and asymmetric absorption bands of COO and CF3-groups in the IR spectrum of the resulting compound in the range of 1200–1800 cm−1. The definite peak of the oscillation of the OH-group at 3683 cm−1 corresponds to the trifluoroacetic acid molecules present in the structure. The broadpeak of the valence oscillations in the range of 3300–3500 cm−1 is caused by the presence of intramolecular hydrogen bonds. Decomposition began at 250°C and 10−2 mm Hg with calcium fluoride CaF2 as the final decomposition product.Conclusions. We obtained a previously undescribed calcium–trifluoroacetic acid complex whose composition can be represented by Ca2(CF3COO)4·8CF3COOH. The crystal island structure is a dimeric molecule where the calcium atoms are bound into dimers by four trifluoroacetate groups. The complex was deposited in the Cambridge Structural Data Bank with a deposit number CCDC 2081186. Although the compound has a molecular structure, thermal decomposition leads to the formation of calcium fluoride characterized by a small particle size, which may further determine its applications.

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.

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.

Gas phase FT-IR spectra and structure of aminoalcohols with intramolecular hydrogen bonds

1999 ◽  
Vol 20 (1) ◽  
pp. 69-83 ◽  
Author(s):  
M. Przesławska ◽  
S.M. Melikowa ◽  
P. Lipkowski ◽  
A. Koll
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Gas Phase ◽  
Intramolecular Hydrogen Bonds ◽  
Ft Ir ◽  
Intramolecular Hydrogen

Manifestation of intramolecular hydrogen bonds in the IR spectra of bioactive aminophenols

2007 ◽  
Vol 102 (4) ◽  
pp. 551-556 ◽  
Author(s):  
G. A. Ksendzova ◽  
G. I. Polozov ◽  
I. V. Skornyakov ◽  
V. L. Sorokin ◽  
G. B. Tolstorozhev ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen
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