scholarly journals Conformational Preferences of cis-1,3-Cyclopentanedicarboxylic Acid and Its Salts by 1H NMR Spectroscopy: Energetics of Intramolecular Hydrogen Bonds in DMSO

2013 ◽  
Vol 78 (5) ◽  
pp. 2005-2011 ◽  
Author(s):  
Bright U. Emenike ◽  
William R. Carroll ◽  
John D. Roberts
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Intramolecular Hydrogen Bonds ◽  
Conformational Preferences ◽  
Intramolecular Hydrogen

Synthesis of 4-Aryl-3(5)-(2-hydroxyphenyl)pyrazoles by Reaction of Isoflavones and their 4-Thio Analogues with Hydrazine Derivatives

2007 ◽  
Vol 60 (12) ◽  
pp. 905 ◽  
Author(s):  
Albert Lévai ◽  
Artur M. S. Silva ◽  
José A. S. Cavaleiro ◽  
José Elguero ◽  
Ibon Alkorta ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Hydrazine Hydrate ◽  
1H Nmr ◽  
Theoretical Calculations ◽  
Intramolecular Hydrogen Bonds ◽  
Nmr Study ◽  
Intramolecular Hydrogen ◽  
New Compounds

4-Aryl-3(5)-2-(hydroxyphenyl)pyrazoles have been prepared by the reaction of isoflavones and their 4-thio analogues with hydrazine hydrate and phenylhydrazine in hot pyridine. The reaction mechanism for the formation of these pyrazoles is discussed. All the new compounds have been fully characterized by NMR spectroscopy. In [D6]DMSO, a 1H NMR study allows observation of the presence of both pyrazole annular tautomers, due to the presence of intramolecular hydrogen bonds in each tautomer (OH···N and NH···O). Theoretical calculations have been carried out on tautomers and conformers of compounds 20 (3(5)-(2-hydroxy-4-methoxyphenyl)-5(3)-methyl-4-phenylpyrazole) and 21 (3(5)-(2-hydroxy-4-methoxyphenyl)-4-(2-methoxyphenyl)-5(3)-methylpyrazole), including the absolute shieldings (GIAO/B3 LYP/6–311++G**) of 21.

scholarly journals A 1H-NMR and MD study of intramolecular hydrogen bonds in methyl β-cellobioside

1992 ◽  
Vol 230 (1) ◽  
pp. 41-61 ◽  
Author(s):  
Bas R. Leeflang ◽  
Johannes F.G. Vliegenthart ◽  
Loes M.J. Kroon-Batenburg ◽  
Bouke P. van Eijck ◽  
Jan Kroon
Keyword(s):  
Hydrogen Bonds ◽  
1H Nmr ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

scholarly journals Molecular dynamics of (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone in solution studied by NMR spectroscopy

2012 ◽  
Vol 10 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Ibrahim Mamedov ◽  
Uwe Eichhoff ◽  
Abel Maharramov ◽  
Musa Bayramov ◽  
Yegana Mamedova
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Rotational Barrier ◽  
Intramolecular Hydrogen Bonds ◽  
Barrier Energy ◽  
Intramolecular Hydrogen

AbstractThe formation of hydrogen bonds and the molecular dynamics for molecules (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone, (E)-4-bromoacetophenone thiosemicarbazone have been investigated in solution using NMR. The results confirm the formation of different O-H…O type intramolecular hydrogen bonds in the oxime molecule. The rotational barrier energy and energy of intramolecular hydrogen bonds have been determined.

Determination of intramolecular hydrogen bonds in amikacin in water solution by NMR spectroscopy

1995 ◽  
Vol 51 (11) ◽  
pp. 1959-1963 ◽  
Author(s):  
Elena Gaggelli ◽  
Nicola Gaggelli ◽  
Antonella Maccotta ◽  
Gianni Valensin ◽  
Domenico Marini ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Water Solution ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

scholarly journals Hydrogen bonding in push-pull 5-substituted-2-alkylidene-4-oxothiazolidines: 1H-MNR spectroscopic study

2003 ◽  
Vol 68 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Markovic ◽  
A. Shirazi ◽  
Zdravko Dzambaski ◽  
Marija Baranac ◽  
Dragica Minic-Popovic
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Solvent Polarity ◽  
Concentration Effect ◽  
Intermolecular Hydrogen Bonding ◽  
Dynamic 1H Nmr

Application of dynamic 1H-NMR spectroscopy added to the understanding of the hydrogen bonds existing in the structurally related 5-substituted-2-alkylidene-4-oxothiazolidines in polar and apolar solvents. The equilibrated mixtures of these typical push-pull alkenes in CDCl3 consist of the intramolecularly H-bonded (E)-isomer and intermolecularly H-bonded (Z)-isomer in varying proportions which depend on the solvent polarity. For the representative of the series (Z)-2-(5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone a concentration effect on the degree of intermolecular hydrogen bonding in apolar CDCl3 has been studied.

Sign in / Sign up

Export Citation Format

Share Document