The intramolecular hydrogen bond in some β-nitroalcohols. Chemistry of nitroalkanes. Part CXIX

1977 ◽  
Vol 55 (13) ◽  
pp. 2504-2509 ◽  
Author(s):  
E. Lipczyńska-Kochany ◽  
T. Urbański
Keyword(s):  
Hydrogen Bond ◽  
Experimental Evidence ◽  
Intramolecular Hydrogen Bond ◽  
Infrared Absorption ◽  
Nmr Spectra ◽  
Absorption Bands ◽  
Intramolecular Hydrogen ◽  
Infrared Absorption Bands

New experimental evidence is given on the existence of an intramolecular hydrogen bond in β-nitroalcohols between the nitro and hydroxylic groups. The conclusion is based on examination of na → π* and infrared absorption bands and nmr spectra.

scholarly journals CP/MASS 13C NMR Spectra of Cellulose Solids: An Explanation by the Intramolecular Hydrogen Bond Concept

1985 ◽  
Vol 17 (5) ◽  
pp. 701-706 ◽  
Author(s):  
Kenji Kamide ◽  
Kunihiko Okajima ◽  
Keisuke Kowsaka ◽  
Toshihiko Matsui
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Intramolecular Hydrogen

Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a 1H/13C NMR Approach

1987 ◽  
Vol 42 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Erhard T. K. Haupt ◽  
Heindirk tom Dieck ◽  
Panayot R. Bontchev
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Complete Analysis ◽  
Solution Structures ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Related Compounds ◽  
C Nmr

AbstractThe complete analysis of the 1H/13 C NMR spectra of α-Pyrophthalone and related compounds demonstrates that the earlier static planar description of the molecules is invalid for polar sol-vents, and here the stability of any intramolecular hydrogen bond is small.

scholarly journals Synthesis and isomerism of hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide

2007 ◽  
Vol 5 (4) ◽  
pp. 996-1006 ◽  
Author(s):  
Zenonas Kuodis ◽  
Albertas Rutavičius ◽  
Algirdas Matijoška ◽  
Olegas Eicher-Lorka
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Hydroxy Group ◽  
Intramolecular Hydrogen Bond ◽  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Imino Group ◽  
Anti Conformer ◽  
Intramolecular Hydrogen

AbstractNew hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide have been obtained and the percentages of anti/syn - conformers were determined. Based on the analyses of 1H NMR spectra, it was concluded that for hydrazones obtained from the 2- hydroxybenzaldehydes and 2’-hydroxycetophenones the ratio between the anti-and syn-conformers depends on the strength of intramolecular hydrogen bond (IMHB) between the nitrogen atom of the imino group and the proton of the 2-hydroxy group. It was shown that increase in IMHB strength results in stabilization of the anti-conformer in solution.

A simple 1H nmr conformational study of some heterocyclic azomethines

1981 ◽  
Vol 59 (8) ◽  
pp. 1205-1207 ◽  
Author(s):  
Francesco A. Bottino ◽  
Maria L. Longo ◽  
Domenico Sciotto ◽  
Michele Torre
Keyword(s):  
Hydrogen Bond ◽  
Chemical Shift ◽  
Intramolecular Hydrogen Bond ◽  
Nmr Spectra ◽  
Variable Temperature ◽  
Rotational Isomerism ◽  
Conformational Study ◽  
Pyrrole Derivatives ◽  
H Nmr ◽  
Intramolecular Hydrogen

The variable temperature 60 MHz 1H nmr spectra of some heterocyclic azomethines exclude the presence of rotational isomerism. Chemical shift values and stereospecific long-range couplings are used to establish that s-trans is the existing conformation. In the case of the pyrrole derivatives a chelated s-trans rotamer is indicated, depending on the presence of an intramolecular hydrogen bond.

scholarly journals THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART VI. THE EFFECT OF STERIC INTERACTIONS ON THE INTRAMOLECULAR HYDROGEN BOND IN o-NITROPHENOL

1960 ◽  
Vol 38 (10) ◽  
pp. 1852-1864 ◽  
Author(s):  
J. C. Dearden ◽  
W. F. Forbes
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bond ◽  
Alkyl Substituent ◽  
Intramolecular Hydrogen Bonding ◽  
Vibration Band ◽  
Absorption Bands ◽  
Steric Interactions ◽  
Stretching Vibration ◽  
Intramolecular Hydrogen

Intramolecular hydrogen bonding occurring in o-nitrophenol is discussed with special reference to the effects of the steric interactions on the absorption bands and on the bonding. An alkyl substituent vicinal to the OH group, or a methyl group vicinal to the NO2 group appears to strengthen the intramolecular hydrogen bond in o-nitrophenol. The O—H vibrational stretching frequency in o-nitrophenol appears to be more susceptible to steric than to mesomeric interactions, and a methyl substituent vicinal to the nitro group in o-nitrophenols is found to give rise to a characteristic O—H stretching vibration band. For 6-t-butyl-2-nitrophenol, a special, "protected" hydrogen bond is postulated. In some of the o-nitrophenols, intermolecular hydrogen bonding gives rise to appreciable ultraviolet intensity decreases presumably because of increased steric interactions.

Effect of the intramolecular hydrogen bond in the active metabolite analogs of leflunomide for blocking the Plasmodium falciparum dihydroorotate dehydrogenase enzyme: QTAIM, NBO, and docking study

2020 ◽  
Vol 16 ◽  
Author(s):  
Reihaneh Heidarian ◽  
Mansoureh Zahedi-Tabrizi
Keyword(s):  
Hydrogen Bond ◽  
Plasmodium Falciparum ◽  
Molecular Orbital ◽  
Intramolecular Hydrogen Bond ◽  
Active Metabolite ◽  
Chemical Hardness ◽  
Dihydroorotate Dehydrogenase ◽  
Molecular Orbital Analysis ◽  
Intramolecular Hydrogen ◽  
Orbital Analysis

: Leflunomide (LFM) and its active metabolite, teriflunomide (TFM), have drawn a lot of attention for their anticancer activities, treatment of rheumatoid arthritis and malaria due to their capability to inhibit dihydroorotate dehydrogenase (DHODH) and Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) enzyme. In this investigation, the strength of intramolecular hydrogen bond (IHB) in five analogs of TFM (ATFM) has been analyzed employing density functional theory (DFT) using B3LYP/6-311++G (d, p) level and molecular orbital analysis in the gas phase and water solution. A detailed electronic structure study has been performed using the quantum theory of atoms in molecules (QTAIM) and the hydrogen bond energies (EHB) of stable conformer obtained in the range of 76-97 kJ/mol, as a medium hydrogen bond. The effect of substitution on the IHB nature has been studied by natural bond orbital analysis (NBO). 1H NMR calculations show an upward trend in the proton chemical shift of the enolic proton in the chelated ring (14.5 to 15.7ppm) by increasing the IHB strength. All the calculations confirmed the strongest IHB in 5-F-ATFM and the weakest IHB in 2-F-ATFM. Molecular orbital analysis, including the HOMO-LUMO gap and chemical hardness, was performed to compare the reactivity of inhibitors. Finally, molecular docking analysis was carried out to identify the potency of inhibition of these compounds against PfDHODH enzyme.

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