Influence of chlorine-substitution in pyrimidine ring on proton donor ability in H-bond and parameters of amino group of 2-amino pyrimidine

2005 ◽  
Vol 37 (1) ◽  
pp. 97-109 ◽  
Author(s):  
V.E. Borisenko ◽  
S.A. Krekov ◽  
M.A. Niyazova ◽  
A. Koll ◽  
P. Lipkowski
Keyword(s):  
Pyrimidine Ring ◽  
Proton Donor ◽  
Amino Group ◽  
Chlorine Substitution ◽  
Donor Ability ◽  
Amino Pyrimidine

scholarly journals The impact of orally administered gadolinium orthovanadate GdVO4:Eu3+ nanoparticles on the state of phospholipid bilayer of erythrocytes

2020 ◽  
Vol 45 (4) ◽  
pp. 389-395
Author(s):  
Anton Tkachenko ◽  
Anatolii Onishchenko ◽  
Vladimir Klochkov ◽  
Nataliya Kavok ◽  
Oksana Nakonechna ◽  
...  
Keyword(s):  
Fluorescent Probes ◽  
Lipid Membranes ◽  
Chemical Properties ◽  
Proton Donor ◽  
The State ◽  
Phospholipid Bilayer ◽  
Erythrocyte Membranes ◽  
Control Group ◽  
Donor Ability ◽  
The Impact

AbstractObjectivesTo assess the state of phospholipid bilayer of red blood cells (RBCs) in rats orally exposed to gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) during two weeks using fluorescent probes − ortho-hydroxy derivatives of 2,5-diaryl-1,3-oxazole.MethodsSteady-state fluorescence spectroscopy: a study by the environment-sensitive fluorescent probes − 2-(2′-OH-phenyl)-5-phenyl-1,3-oxazole (probe O1O) and 2-(2′-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7).ResultsNo significant changes are detected in the spectra of the fluorescent probes bound to the RBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that, in case of the rats orally exposed to nanoparticles, no noticeable changes in physico-chemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of RBCs in the region, where the probes locate.ConclusionsNo changes in the physical and chemical properties of the erythrocyte membranes are detected in the region from glycerol backbones of phospholipids to the center of the phospholipid bilayer in the rats orally exposed to VNPs during 2 weeks.

scholarly journals Breaking the Carboxyl Rule

2013 ◽  
Vol 288 (29) ◽  
pp. 21254-21265 ◽  
Author(s):  
Sergei P. Balashov ◽  
Lada E. Petrovskaya ◽  
Eleonora S. Imasheva ◽  
Evgeniy P. Lukashev ◽  
Andrei K. Dioumaev ◽  
...  
Keyword(s):  
Schiff Base ◽  
Water Molecule ◽  
Proton Pump ◽  
Rate Constants ◽  
Proton Donor ◽  
Carboxyl Group ◽  
Amino Group ◽  
Wild Type ◽  
Fast Phase ◽  
Proton Uptake

A lysine instead of the usual carboxyl group is in place of the internal proton donor to the retinal Schiff base in the light-driven proton pump of Exiguobacterium sibiricum (ESR). The involvement of this lysine in proton transfer is indicated by the finding that its substitution with alanine or other residues slows reprotonation of the Schiff base (decay of the M intermediate) by more than 2 orders of magnitude. In these mutants, the rate constant of the M decay linearly decreases with a decrease in proton concentration, as expected if reprotonation is limited by the uptake of a proton from the bulk. In wild type ESR, M decay is biphasic, and the rate constants are nearly pH-independent between pH 6 and 9. Proton uptake occurs after M formation but before M decay, which is especially evident in D2O and at high pH. Proton uptake is biphasic; the amplitude of the fast phase decreases with a pKa of 8.5 ± 0.3, which reflects the pKa of the donor during proton uptake. Similarly, the fraction of the faster component of M decay decreases and the slower one increases, with a pKa of 8.1 ± 0.2. The data therefore suggest that the reprotonation of the Schiff base in ESR is preceded by transient protonation of an initially unprotonated donor, which is probably the ϵ-amino group of Lys-96 or a water molecule in its vicinity, and it facilitates proton delivery from the bulk to the reaction center of the protein.

IR-spectroscopic evaluation of proton-donor ability of HCl, HBr, HI acids and HSO3CF3, HClO4, HGeCl3, HAlCl4 superacids

1983 ◽  
Vol 32 (3) ◽  
pp. 636-637
Author(s):  
V. B. Kazanskii ◽  
O. M. Nefedov ◽  
A. A. Pankov ◽  
V. Yu. Borovkov ◽  
S. P. Kolesnikov ◽  
...  
Keyword(s):  
Proton Donor ◽  
Donor Ability ◽  
Ir Spectroscopic

scholarly journals The inhibition of the proton donor ability of bicarbonate promotes the electrochemical conversion of CO2 in bicarbonate solutions

2021 ◽  
Vol 48 ◽  
pp. 101521
Author(s):  
Oriol Gutiérrez-Sánchez ◽  
Nick Daems ◽  
Willem Offermans ◽  
Yuvraj Y. Birdja ◽  
Metin Bulut ◽  
...  
Keyword(s):  
Proton Donor ◽  
Electrochemical Conversion ◽  
Donor Ability ◽  
Bicarbonate Solutions

scholarly journals Synthesis, solid-state fluorescence properties, and computational analysis of novel 2-aminobenzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides

2012 ◽  
Vol 8 ◽  
pp. 266-274 ◽  
Author(s):  
Kenichirou Yokota ◽  
Masayori Hagimori ◽  
Naoko Mizuyama ◽  
Yasuhisa Nishimura ◽  
Hiroshi Fujito ◽  
...  
Keyword(s):  
Solid State ◽  
Quantum Chemical ◽  
Computational Analysis ◽  
Pyrimidine Ring ◽  
Amino Group ◽  
Pyrimidine Derivatives ◽  
Ketene Dithioacetals ◽  
Solid State Fluorescence ◽  
Guanidine Carbonate ◽  
Fluorescent Compounds

New fluorescent compounds, benzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides (3a–g), 2-amino-4-methylsulfanylbenzo[4,5]thieno[3,2-d]pyrimidine (6), and 2-amino-4-methylsulfanyl-7-methoxybenzo[4,5]furo[3,2-d]pyrimidine (7), were synthesized in good yields from heterocyclic ketene dithioacetals (1a–c) and guanidine carbonate (2a) or (S)-methylisothiourea sulfate (2b) in pyridine under reflux. Among the fused pyrimidine derivatives, compound 3c, which has an amino group at the 2-position and a benzylamino group at the 4-position of the pyrimidine ring, showed the strongest solid-state fluorescence. The absorption and emission properties of the compounds were quantitatively reproduced by a series of ab initio quantum-chemical calculations.

Structure and proton-donor ability of N-(1-trifluoromethylsulfonylamino-2,2,2-trichloroethyl)-acrylamide

2009 ◽  
Vol 79 (6) ◽  
pp. 1146-1151 ◽  
Author(s):  
L. P. Oznobikhina ◽  
N. N. Chipanina ◽  
B. A. Shainyan ◽  
T. N. Aksamentova ◽  
E. V. Kondrashov ◽  
...  
Keyword(s):  
Proton Donor ◽  
Donor Ability

scholarly journals Acidity of HOCN, HSCN, HNCO, HNCS: A treatment from the viewpoint of ab initio approach

2005 ◽  
Vol 70 (10) ◽  
pp. 1183-1192 ◽  
Author(s):  
Alexei Pankratov ◽  
Sergei Khmelev
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Thermodynamic Stability ◽  
Electronic Structures ◽  
Proton Donor ◽  
Electronic Correlation ◽  
Medium Effects ◽  
General Sequence ◽  
Donor Ability ◽  
Ab Initio Approach

The electronic structures of the molecules HOCN, HSCN, HNCO, HNCS and the anions OCN -, SCN - have been investigated ab initio at the RHF/6-31G(d) RHF/6-31G(d,p), MP2/6-31G(d)//RHF/6-31G(d) and MP2/6-31G(d,p)//RHF/6-31G(d,p) theory levels. The thermodynamic stability of the HNCO and HNCS molecules was shown to be higher than that of the HOCH and HSCN molecules, respectively. The following series of the alteration of the protolytes strength HSCN > HOCH HNCS > HNCO, HOCN > HNCO, HSCN > HNCS was substantiated. The computations taking into account the electronic correlation (MP2/6-31G(d)//RHF/6-31G(d) and MP2/6-31G(d,p)//RHF/6-31G(d,p)) reflect the general sequence of change in the pro- ton-donor properties: HSCN > HOCN > HNCS > HNCO, coinciding with the order of descending hydrophobicity of the compounds. The comparative proton-donor ability of the above acids in aqueous solutions is determined basically from the electronic structure and size of their molecules and anions OCN -, SCN -, but not on medium effects.

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