Synthesis and conformation of some 6-aminomethyluracil amides

1990 ◽  
Vol 55 (11) ◽  
pp. 2731-2737 ◽  
Author(s):  
Ivan Stibor ◽  
David Šaman ◽  
Pavel Fiedler
Keyword(s):  
Hydrogen Bond ◽  
Ir Spectroscopy ◽  
Intramolecular Hydrogen Bond ◽  
Amide Carbonyl ◽  
Intramolecular Hydrogen

Three model amides (I-III) derived from 6-(N-alkylaminomethyl)-uracil and arylcarboxylic acids were synthesized and their conformation in solution studied. The 7-membered intramolecular hydrogen bond between amide carbonyl and H-N1 of uracil nucleus was proved to exist in solution of all three compounds using NMR and IR spectroscopy.

scholarly journals Hydroquinone-Based Anion Receptors for Redox-Switchable Chloride Binding

Chemistry ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Daniel A. McNaughton ◽  
Xiaochen Fu ◽  
William Lewis ◽  
Deanna M. D’Alessandro ◽  
Philip A. Gale
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
Binding Mode ◽  
Chloride Binding ◽  
Binding Studies ◽  
Secondary Interaction ◽  
Amide Carbonyl ◽  
Internal Hydrogen Bond ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonding Site

A series of chloride receptors has been synthesized containing an amide hydrogen bonding site and a hydroquinone motif. It was anticipated that oxidation of the hydroquinone unit to quinone would greatly the diminish chloride binding affinity of these receptors. A conformational switch is promoted in the quinone form through the formation of an intramolecular hydrogen bond between the amide and the quinone carbonyl, which blocks the amide binding site. The reversibility of this oxidation process highlighted the potential of these systems for use as redox-switchable receptors. 1H-NMR binding studies confirmed stronger binding capabilities of the hydroquinone form compared to the quinone; however, X-ray crystal structures of the free hydroquinone receptors revealed the presence of an analogous inhibiting intramolecular hydrogen bond in this state of the receptor. Binding studies also revealed interesting and contrasting trends in chloride affinity when comparing the two switch states, which is dictated by a secondary interaction in the binding mode between the amide carbonyl and the hydroquinone/quinone couple. Additionally, the electrochemical properties of the systems have been explored using cyclic voltammetry and it was observed that the reduction potential of the system was directly related to the expected strength of the internal hydrogen bond.

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.

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

(1′R,3S)-2-Oxo-1-(1′-phenylethyl)piperidine-3-carboxylic acid: a case of a very strong intramolecular hydrogen bond

2004 ◽  
Vol 60 (11) ◽  
pp. o2110-o2112
Author(s):  
Ana-María Lumbreras-García ◽  
Alberto Galindo-Guzmán ◽  
Dino Gnecco ◽  
Joel-Luis Terán ◽  
Sylvain Bernès
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Intramolecular Hydrogen Bond ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond
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