Rapid Commun Mass Spectrom
Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
Published: December 2007
The electron ionization mass spectra of five series of seven 2-aryl,4-R-substituted (R = Me, Et, i-Pr, t-Bu or Ph) 3,4,5,6-tetrahydro-2H-1,3-oxazines were recorded at 14 and 70 eV in order to study the ring-chain tautomeric equilibria in the gas phase. Certain fragment ions were associated with the ring or with the open-chain forms of the compounds. As in chloroform solution, the electron-withdrawing effect of the aryl substituent (p-NO(2), m-Br, p-Cl, H, p-Me, p-OMe and p-NMe(2)) shifts the equilibrium towards the ring form. The correlation of ring-chain equilibria (log K = [ring]/[chain]) with the Hammett sigma+ constants of the aryl substituents was in general good or satisfactory although in some cases the p-NMe(2) did not fit these correlations.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/rcm.3260 | DOI Listing |
J Pestic Sci
November 2024
Graduate School of Agriculture, Ehime University.
The enantiospecific anti-phytopathogenic fungal activity of a new type of coumarin bearing a phenylpropanoid unit at the 3-position was found. ()-3-[1-Methoxy-3-(4-methoxyphenyl)prop-2-yl]coumarin (()-: EC=16.5 µM) was 30 times more effective than the ()-form against the Japanese pear pathotype.
View Article and Find Full Text PDFJ Appl Toxicol
January 2025
Laboratory of Genetic Toxicology, Lutheran University of Brazil (ULBRA), Canoas, Rio Grande do Sul, Brazil.
The widespread use of electronic devices has led to increased blue light exposure, highlighting the need for effective radiation blockers with blue light protection. Two synthetic 2-(2'-hydroxyphenyl)benzoxazole derivatives named azo-4'-benzoxazole and azo-5'-benzoxazole have shown an unprecedented blue light absorption capacity but had not been subjected to a safety evaluation. This study aimed to evaluate the cytotoxic, genotoxic, and mutagenic activities of these compounds.
View Article and Find Full Text PDFNanotechnology
January 2025
Institute of Nano Science and Technology, Knowledge City, Sector 81, Mohali, 140306, INDIA.
This study investigates simple acetylenes substituted with phenylurea as a constant H-bonding unit (Alk-R) and varied hydrophobic units (R = H, Phenyl (Ph), Phenylacetylene (PA), Ph-NMe2) to understand self-assembly properties driven by synergistic non-covalent interactions. Our observations reveal hierarchical self-assembled fibrillar networks with luminescent needles, fibers, and flowers on nano- to micro-meter scales. Subtle changes in substituents led to significant differences: H, Ph, PA, and Ph-NMe2 produced needle-like crystals, dendritic nanofibers, microflakes, and no self-assembly, respectively.
View Article and Find Full Text PDFJ Biomol Struct Dyn
January 2025
Department of Chemistry, National Institute of Technology Silchar, Silchar, Assam, India.
A series of 2,6-di(pyrazine-2-yl)pyridine (dppy) ligands - of varying substituents of different electronic nature (-NMe, -OMe,-Me, and -Cl) in the 4-position of the pyridine moiety has been designed and synthesized to study the binding behavior of the dppy ligands towards Bovine Serum Albumin (BSA), a low-cost serum albumin protein. The interaction between ligands and BSA has been studied using UV-Visible and fluorescence spectroscopy and molecular docking studies. The fluorescence of BSA was found to be quenched in the presence of all the ligands , in which ligand , having the most electron donating group NMe exhibits the maximum binding affinity towards BSA.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh.
This work represents a systematic computational study of structural and optoelectronic properties of 24 phenylazo-2-naphthol derivatives using the DFT-B3LYP/6-31 + G(d,p) method. The positional isomers of azo compounds have been designed by introducing an azophenyl unit (with and without substituents) at three different (1-, 3-, and 4-) positions of 2-naphthols. This result shows that depending on the linking position of the azophenyl unit and substituents (NO and maleimide), the -azo, -azo, and hydrazo forms of our substituted azo derivatives possess distinguished UV-vis absorption and charge-transfer properties compared to unsubstituted Sudan I derivatives.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!
© LitMetric 2025. All rights reserved.