The first-stage acid-base equilibrium of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1,3)-dione was studied for the first time in aqueous solutions. Its constant (pK = 9.23 ± 0.03) and thermodynamic parameters (Δ = 52 ± 1 kJ·mol, Δ = 83 ± 1 kJ·mol, and Δ = 103 ± 4 J·mol·K) were determined by potentiometric titration. Computational analysis, including molecular dynamics (MD) simulations and quantum chemical calculations, was conducted to evaluate solvation effects and proton dissociation sites. MD simulations identified distinct solvation shells and interactions with water molecules, while quantum chemical calculations highlighted the primary deprotonation site. Fuzzy bond order (FBO) analysis and energy calculations of anionic forms corroborated these findings, demonstrating a strong correlation between the Δ and FBO values. The research established the dissociation sequence for conformational - and -isomers of the title compound and validated the FBO method as an efficient tool for assessing dissociation processes in polybasic acids.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.jpca.4c05989 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Acid-Base Equilibrium of 5,5,6-Trihydroxy-6-Methyldihydropyrimidine-2,4(1,3)-Dione in the Gas Phase and in Water.
J Phys Chem A
January 2025
Ufa Institute of Chemistry, Ufa Federal Research Centre of the Russian Academy of Sciences, Laboratory of Physicochemical Methods of Analysis, 69 Prospekt Oktyabrya, Ufa 450054, Russian Federation.
The first-stage acid-base equilibrium of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1,3)-dione was studied for the first time in aqueous solutions. Its constant (pK = 9.23 ± 0.
View Article and Find Full Text PDFEffect of isotonic sodium bicarbonate infusion on perioperative acid-base status among patients undergoing emergency laparotomy for perforation peritonitis (ISABEL trial): a randomized controlled trial.
Eur J Trauma Emerg Surg
January 2025
Department of Anaesthesia & Intensive Care, Postgraduate Institute of Medical Education and Research (PGIMER), Sector-12, Chandigarh, 160012, India.
Purpose: Perioperative metabolic acidosis negatively affects patient outcomes. Perioperative fluid therapy has a clinically significant effect on acid-base balance. This study was conducted to evaluate the effects of isotonic sodium bicarbonate infusion (ISB) versus balanced crystalloid solution (BCS) on perioperative acid-base balance, in terms of postoperative base excess, among patients undergoing emergency laparotomy for perforation peritonitis.
View Article and Find Full Text PDFHydrogel formed in situ through Schiff base reaction between gallic acid-grafted soybean protein isolate and oxidized dextran: Interactions, physicochemical properties, and digestive characteristics.
Food Chem
January 2025
College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China. Electronic address:
Herein, we developed multifunctional hydrogels formed between soybean protein (SPI)-gallic acid conjugate and oxidized dextran (ODex) via a Schiff base reaction. The effects of ODex on the morphology, structure, and functional properties of the hydrogels were elucidated. The results showed that the crosslinking modes in the hydrogels include hydrogen bonding, Schiff bases, Michael addition, and π-π stacking.
View Article and Find Full Text PDFEvidence for intrinsic DNA dynamics and deformability in damage sensing by the Rad4/XPC nucleotide excision repair complex.
Nucleic Acids Res
January 2025
Department of Physics, 845 W Taylor St, University of Illinois Chicago, Chicago, IL 60607, USA.
Altered DNA dynamics at lesion sites are implicated in how DNA repair proteins sense damage within genomic DNA. Using laser temperature-jump (T-jump) spectroscopy combined with cytosine-analog Förster Resonance Energy Transfer (FRET) probes that sense local DNA conformations, we measured the intrinsic dynamics of DNA containing 3 base-pair mismatches recognized in vitro by Rad4 (yeast ortholog of XPC). Rad4/XPC recognizes diverse lesions from environmental mutagens and initiates nucleotide excision repair.
View Article and Find Full Text PDFComparing integrative ventilatory and renal acid-base acclimatization in lowlanders and Tibetan highlanders during ascent to 4,300 m.
Proc Natl Acad Sci U S A
January 2025
Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB T3E 6K6, Canada.
With over 14 million people living above 3,500 m, the study of acclimatization and adaptation to high altitude in human populations is of increasing importance, where exposure to high altitude (HA) imposes a blood oxygenation and acid-base challenge. A sustained and augmented hypoxic ventilatory response protects oxygenation through ventilatory acclimatization, but elicits hypocapnia and respiratory alkalosis. A subsequent renally mediated compensatory metabolic acidosis corrects pH toward baseline values, with a high degree of interindividual variability.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!