Studies on intramolecular hydrogen bonding between the pyridine nitrogen and the amide hydrogen of the peptide: synthesis and conformational analysis of tripeptides containing novel amino acids with a pyridine ring

2005 ◽  
Vol 11 (8) ◽  
pp. 491-498 ◽  
Author(s):  
Masayuki Hanyu ◽  
Daisuke Ninomiya ◽  
Ryoji Yanagihara ◽  
Takashi Murashima ◽  
Toshifumi Miyazawa ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Peptide Synthesis ◽  
Pyridine Ring ◽  
Intramolecular Hydrogen Bonding ◽  
Amide Hydrogen ◽  
Pyridine Nitrogen ◽  
Intramolecular Hydrogen

scholarly journals Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

2013 ◽  
Vol 9 ◽  
pp. 1127-1134 ◽  
Author(s):  
Josué M Silla ◽  
Rodrigo A Cormanich ◽  
Roberto Rittner ◽  
Matheus P Freitas
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Conformational Equilibrium ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Coupling Constant ◽  
Intramolecular Hydrogen ◽  
Phenylboronic Acids ◽  
Electron Donation

A 1 TS J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF→σ*OH hydrogen bond that would be expected in 2-fluorophenol. 2-Fluorophenylborane (3), which does not experience hydrogen bonding, was used to verify whether nF→pB interaction governs the conformational equilibrium in 1 due to a predominant OH∙∙∙F hydrogen bond or to other effects. A series of 2-X-phenylboranes (X = Cl, Br, NH2, PH2, OH and SH) were further computationally analyzed to search for electron donors to boron, capable of influencing the conformational equilibrium. Overall, the intramolecular OH∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1 h J F,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the corresponding conformers appreciably populated, because of steric effects and the loss of πCC→pB resonance. Thus, the results found earlier for 2-fluorophenol about the lack of intramolecular hydrogen bonding are now corroborated.

Structural and Spectral Studies of Palladium (II) Complexes of Pyridil bis{3-Piperidyl-, bis{Hexamethyleneiminyl-, bis{N(4)-Diethyl- and bis{N(4)-Dipropylthiosemicarbazone}

2000 ◽  
Vol 55 (9) ◽  
pp. 863-870 ◽  
Author(s):  
Alfonso Castiñeiras ◽  
Maria Gil ◽  
Elena Bermejo ◽  
Douglas X. West
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Intramolecular Hydrogen Bonding ◽  
Isomeric Form ◽  
Spectral Studies ◽  
Imine Nitrogen ◽  
Pyridine Nitrogen ◽  
Square Planar ◽  
Intramolecular Hydrogen ◽  
C Nmr

Pyridil bis{N(4)-substituted thiosemicarbazones}, in which the substituents replacing the NH2 group on the thiosemicarbazone moieties are piperidyl, H2Plpip; hexamethyleneiminyl, H2Plhexim; diethylamino, H2Pl4DE; and dipropylamino, H2PI4 DP, have been synthesized. Representative palladium(II) complexes of these bis (thiosemicarbazones) have been characterized by IR, electronic, mass, and 1H and 13C NMR spectroscopy. Crystal structures have been determined for H2Plhexim and two of its palladium(II) complexes. H2Plhexim is in the Z isomeric form with intramolecular hydrogen bonding from both thiosemicarbazone moieties to pyridine nitrogens. [Pd(Plhexim)] has square-planar N2S2 coordination (i.e., imine nitrogen and thiolato sulfur atoms). [Pd2 (Plhexim)Cl2 · DMSO has two PdNNSCl centers with the pyridine nitrogen, imine nitrogen or hydrazinic nitrogen and thiolato sulfur atoms coordinated

Intramolecular Hydrogen Bonding in α-Epoxy Alcohols: A Conformational Analysis of 1,2-Dialkyl-2,3-epoxycyclopentanol Diastereomers

2018 ◽  
Vol 47 (2) ◽  
pp. 156-159 ◽  
Author(s):  
Yasmeen A. Abdo ◽  
Justin W. Weeks ◽  
William Layfield ◽  
William M. Tremlett ◽  
Joshua W. Graham ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Intramolecular Hydrogen Bonding ◽  
Epoxy Alcohols ◽  
Intramolecular Hydrogen

Conformational analysis and intramolecular hydrogen bonding of cis-3-aminoindan-1-ol: a quantum chemical study

2013 ◽  
Vol 19 (11) ◽  
pp. 4837-4847 ◽  
Author(s):  
Djaffar Kheffache ◽  
Hind Guemmour ◽  
Azzedine Dekhira ◽  
Ahmed Benaboura ◽  
Ourida Ouamerali
Keyword(s):  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen
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