(1)H and (13)C NMR spectroscopic data for 5alpha-androstanes and halo-5alpha-androstanes with different substituents at positions C-3, C-9, C-11 and C-17 were examined and assigned by a combination of 1D and 2D NMR experiments. The substituent effects on the (13)C chemical shifts were compared with those of epi-androsterone, used as a reference compound. The coupling constants (n)J((19)F,(13)C) were measured for compounds 6, 8, 11 and 14.
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J Magn Reson
December 2024
Department of Medicine, University of Alberta, Canada; Department of Biochemistry, University of Alberta, Canada. Electronic address:
Solution NMR studies of large systems are hampered by rapid signal decay. We hereby introduce ROCSY (relaxation-optimized total correlation spectroscopy), which maximizes transfer efficiency across J-coupling-connected spin networks by minimizing the amount of time magnetization spends in the transverse plane. Hard pulses are substituted into the Clean-CITY TOCSY pulse element first developed by Ernst and co-workers, allowing for longer delays in which magnetization is aligned along the z-axis.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing 100085, China.
Vinylene-linked Covalent Organic Frameworks (V-2D-COFs) are a class of promising porous organic materials that feature fully π-conjugated structures, high crystallinity, ultrahigh chemical stability, and extraordinary optoelectronic properties. However, the types of reactions and the availability of monomers for synthesizing linked COFs are considerably limited by the irreversibility of the C═C bond, and the complete π-conjugated structure restricts their in-depth research in hydrophilicity, membrane materials, and proton conductivity. Postsynthetic modification (PSM), which can avoid these problems by incorporating functional moieties into the predetermined framework, provides an alternative way to construct diverse V-2D-COFs.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Rensselaer Polytechnic Institute, Troy, NY, USA.
Background: Heparan sulfate (HS) interacts with many important proteins. These interactions are primarily driven by electrostatics, with specificity determined by sulfation patterns. Although 3-O-sulfation is a rare modification in HS, several genome-wide association studies (GWAS) revealed that the Hs3st1 gene, encoding HS-3-O-sulfotransferase-1, is significantly linked to late onset AD risk.
View Article and Find Full Text PDFMol Divers
January 2025
College of Chemistry and Materials Engineering, Zhejiang A&F University, Hangzhou, 311300, China.
A series of novel isatin-oxime ether derivatives were designed, synthesized and characterized by H NMR and C NMR and HRMS. These compounds were evaluated for their in vitro cytotoxicity against three human cancer cell lines (A549, HepG2 and Hela) by MTT assay. According to the experimental results, compounds 6a (IC = 0.
View Article and Find Full Text PDFSci Rep
January 2025
Chemistry Department, Faculty of Science, Alexandria University, P.O. Box 426, Alexandria, 21321, Egypt.
New formyl indole derivatives based on thiobarbituric acid were designed for targeting parasitological applications. The new compounds (5-((1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (3a), and 5-((1-benzyl-1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (3b) were synthesized as thioxodihydropyrimidine derivatives via aldol condensation reaction. The structures of the synthesized compounds were confirmed based on their spectral data via FT-IR, H and C NMR spectral characterization.
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