4.12.3.2 Prototropic tautomerism in the imidazole ring of common purines

2005 ◽  
pp. 315-315
Author(s):  
D. Shugar ◽  
A. Psoda
Keyword(s):  
Imidazole Ring ◽  
Prototropic Tautomerism

Prototropic Tautomerism and Some Features of the IR Spectra of 2-(3-Chromenyl)-1-hydroxyimidazoles

2019 ◽  
Vol 72 (9) ◽  
pp. 699 ◽  
Author(s):  
Polina A. Nikitina ◽  
Tatiana Yu. Koldaeva ◽  
Vitaly S. Mityanov ◽  
Vladimir S. Miroshnikov ◽  
Elizaveta I. Basanova ◽  
...  
Keyword(s):  
Solid State ◽  
Ir Spectra ◽  
Carbonyl Group ◽  
Tautomeric Form ◽  
Imidazole Ring ◽  
General Effect ◽  
Dmso Solution ◽  
Prototropic Tautomerism ◽  
Leading Role ◽  
Equilibrium Shift

Prototropic tautomerism of 2-(3-chromenyl)-1-hydroxyimidazoles with various substituents in the chromenyl moiety (1-hydroxyimidazole – imidazole N-oxide) was studied by means of 1H NMR and IR spectroscopies. It was demonstrated that in d6-DMSO solution, the substituents in the chromenyl ring have no influence on the equilibrium shift: the prevalence of the N-oxide tautomeric form is caused by the possibility of stabilization of the planar structure with the help of the carbonyl group in position 5 of the imidazole ring. In contrast, in the solid state the general effect of the chromenyl substituent in position 2 of imidazole plays the leading role. The increase in general electron-withdrawing effect of the chromenyl moiety leads to the prevalence of the imidazole N-oxide tautomer.

Action of Thioglycosides of 1,2,4-Triazoles and Imidazoles on the Oxidative Stress and Glycosidases in Mice with Molecular Docking

2019 ◽  
Vol 16 (6) ◽  
pp. 696-710
Author(s):  
Mahmoud Balbaa ◽  
Doaa Awad ◽  
Ahmad Abd Elaal ◽  
Shimaa Mahsoub ◽  
Mayssaa Moharram ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Docking ◽  
Active Sites ◽  
Biological Activities ◽  
Imidazole Ring ◽  
Quantitative Structure Activity Relationship ◽  
Binding Interaction ◽  
Qsar Study

Background: ,2,3-Triazoles and imidazoles are important five-membered heterocyclic scaffolds due to their extensive biological activities. These products have been an area of growing interest to many researchers around the world because of their enormous pharmaceutical scope. Methods: The in vivo and in vitro enzyme inhibition of some thioglycosides encompassing 1,2,4- triazole N1, N2, and N3 and/or imidazole moieties N4, N5, and N6. The effect on the antioxidant enzymes (superoxide dismutase, glutathione S-transferase, glutathione peroxidase and catalase) was investigated as well as their effect on α-glucosidase and β-glucuronidase. Molecular docking studies were carried out to investigate the mode of the binding interaction of the compounds with α- glucosidase and β -glucuronidase. In addition, quantitative structure-activity relationship (QSAR) investigation was applied to find out the correlation between toxicity and physicochemical properties. Results: The decrease of the antioxidant status was revealed by the in vivo effect of the tested compounds. Furthermore, the in vivo and in vitro inhibitory effects of the tested compounds were clearly pronounced on α-glucosidase, but not β-glucuronidase. The IC50 and Ki values revealed that the thioglycoside - based 1,2,4-triazole N3 possesses a high inhibitory action. In addition, the in vitro studies demonstrated that the whole tested 1,2,4-triazole are potent inhibitors with a Ki magnitude of 10-6 and exhibited a competitive type inhibition. On the other hand, the thioglycosides - based imidazole ring showed an antioxidant activity and exerted a slight in vivo stimulation of α-glucosidase and β- glucuronidase. Molecular docking proved that the compounds exhibited binding affinity with the active sites of α -glucosidase and β-glucuronidase (docking score ranged from -2.320 to -4.370 kcal/mol). Furthermore, QSAR study revealed that the HBD and RB were found to have an overall significant correlation with the toxicity. Conclusion: These data suggest that the inhibition of α-glucosidase is accompanied by an oxidative stress action.

scholarly journals Homogeneous Escherichia coli FPG protein. A DNA glycosylase which excises imidazole ring-opened purines and nicks DNA at apurinic/apyrimidinic sites.

1990 ◽  
Vol 265 (7) ◽  
pp. 3916-3922
Author(s):  
S Boiteux ◽  
T R O'Connor ◽  
F Lederer ◽  
A Gouyette ◽  
J Laval
Keyword(s):  
Escherichia Coli ◽  
Protein A ◽  
Imidazole Ring ◽  
Dna Glycosylase

scholarly journals A METHOD FOR PROTECTING THE IMIDAZOLE RING OF HISTIDINE DURING CERTAIN REACTIONS AND ITS APPLICATION TO THE PREPARATION OF l-AMINO-N-METHYLHISTIDINE

1937 ◽  
Vol 117 (1) ◽  
pp. 27-36
Author(s):  
Vincent du Vigneaud ◽  
Otto K. Behrens
Keyword(s):  
Imidazole Ring

scholarly journals Participation of an Intermediate Sulfoxide in the Enzymatic Thiolation of the Imidazole Ring of Hercynine to Form Ergothioneine

1974 ◽  
Vol 249 (14) ◽  
pp. 4420-4427
Author(s):  
Yoshinori Ishikawa ◽  
Sheila E. Israel ◽  
Donald B. Melville
Keyword(s):  
Imidazole Ring

scholarly journals Stabilization of the imidazole ring of His-195 at the active site of chloramphenicol acetyltransferase

1991 ◽  
Vol 266 (18) ◽  
pp. 11695-11698
Author(s):  
I.A. Murray ◽  
A. Lewendon ◽  
W.V. Shaw
Keyword(s):  
Active Site ◽  
Imidazole Ring ◽  
Chloramphenicol Acetyltransferase

Quantum-chemical description of the prototropic tautomerism of pyrimidine bases

2009 ◽  
Vol 45 (6) ◽  
pp. 680-684 ◽  
Author(s):  
J. A. Kereselidze ◽  
Z. V. Pachulia ◽  
T. Sh. Zarqua
Keyword(s):  
Quantum Chemical ◽  
Prototropic Tautomerism ◽  
Pyrimidine Bases ◽  
Chemical Description

Cyclisation of histidine containing peptides in the solid-phase by anchoring the imidazole ring to trityl resins

1999 ◽  
Vol 40 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Giuseppina Sabatino ◽  
Mario Chelli ◽  
Silvia Mazzucco ◽  
Mauro Ginanneschi ◽  
Anna Maria Papini
Keyword(s):  
Solid Phase ◽  
Imidazole Ring
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