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4(3H)-Pyrimidinone is observed in nature in equilibrium with other tautomeric forms, mimicking the tautomeric equilibrium in pyrimidine nucleobases. In this work, the enthalpy of formation in the gaseous phase of 4(3H)-pyrimidinone was derived from the combination of the enthalpy of formation in the crystalline phase, obtained by static bomb combustion calorimetry, and the enthalpy of sublimation, obtained by Knudsen effusion. The gaseous phase enthalpy of formation of 4(3H)-pyrimidinone was interpreted in terms of isodesmic reactions that consider the enthalpic effects of hydroxypyridines and pyrimidine. After comparison of the experimental and computational results, the same type of isodesmic reactions was used to study the substituent effects of the hydroxyl functional group of 2-, 4-, and 5-hydroxypyrimidines. The influence of aromaticity on the energetics of hydroxypyrimidines was evaluated using the variation of nucleus-independent chemical shifts for several reactions. The influence of intramolecular hydrogen bonds was investigated using the quantum theory of atoms in molecules and the geometric rule of Baker and Hubbard to identify hydrogen bonds. The energetic results obtained were also interpreted in terms of an in plane anomeric effect in the pyrimidine ring.
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http://dx.doi.org/10.1021/jp502468s | DOI Listing |
PLoS One
September 2025
Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt.
Polar protic and aprotic solvents can effectively simulate the maturation of breast carcinoma cells. Herein, the influence of polar protic solvents (water and ethanol) and aprotic solvents (acetone and DMSO) on the properties of 3-(dimethylaminomethyl)-5-nitroindole (DAMNI) was investigated using density functional theory (DFT) computations. Thermodynamic parameters retrieved from the vibrational analysis indicated that the DAMNI's entropy, heat capacity, and enthalpy increased with rising temperature.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Center for Advanced Structural Materials, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
Increasing evidences show the significance of low melting entropy in glass formation of substances. Our previous studies have uncovered the strong dependence between melting entropy in the eutectic mixtures and mixing enthalpy, which has been serving as an important reference for glass formation, showing that negative mixing enthalpy largely reduces the melting entropy. In this paper, we focused on the question as to how melting entropy is associated with another classical glass formation criterion of molecule/atom size difference of components.
View Article and Find Full Text PDFFood Res Int
November 2025
Department of Food and Drug, University of Parma, Viale Parco Area delle Scienze, 43124 Parma, Italy; Institute of Biophysics, National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy.
The hop plant is gaining interest in the food, pharmaceutical, and cosmetics industries due to its abundance of secondary metabolites. However, branches and leaves, despite their antioxidant potential, are typically discarded. To valorize these components as functional ingredients they were dried, milled into hop powder (HP), and used to enrich bread.
View Article and Find Full Text PDFFood Res Int
November 2025
School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, PR China; Anqing Yixiu Green Food Innovation Research Institute, Anqing 246000, PR China. Electronic address:
This study presents a biopreservation method using sourdough co-fermented with Fructilactobacillus sanfranciscensis and Propionibacterium freudenreichii, optimizing conditions to 220 hydration and 24 h fermentation. The composite sourdough bread quality was evaluated through physicochemical, storage, sensory, and microbial tests, with mechanisms analyzed based on microstructure, rheology, and dough structure. Results showed that: first, the composite sourdough enhanced bread physicochemical properties, increasing volume, height-to-diameter ratio, elasticity, and resilience, while reducing baking loss, hardness, chewiness, and adhesiveness.
View Article and Find Full Text PDFOrg Lett
September 2025
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russian Federation.
The design and synthesis of advanced energetic non-hydrogen 1,2,5-oxadiazole assemblies were realized. All target azo-1,2,5-oxadiazole assemblies have high densities (1.89-1.
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