[reaction: see text] Six-membered cyclic phosphates (2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes) bearing an internal protected or unprotected hydroxyl group were designed, synthesized, and studied by NMR and computational methods. Selective opening of O-isopropylidene-protected 1,2-diols at the primary site was achieved with either triethylsilane or trimethylallylsilane in the presence of BF3.OEt2. Applied to 5,6-O-isopropylidenepentofuranosides, this reaction gave rise to the formation of the corresponding 1,3-diol precursors for the six-membered ring phosphates containing an O-isopropyl or O-1,1-dimethyl-3-butenyl functional group at C-6. The O-1,1-dimethyl-3-butenyl protecting group was efficiently removed after the phosphorylation with BF3.OEt2, and the six-membered cyclic phosphates containing free hydroxyl groups were obtained. A cyclic phosphate with a free hydroxyl group oriented cis to the phosphoryl group shows a vicinal coupling constant 3J(HP) that is in accordance with the chair conformation. This is due to the formation of a seven-membered intramolecular hydrogen-bonded ring structure that stabilizes the chair conformation. Thus, the strong tendency of the phenoxy group to be in an axial position is diminished by the internal hydrogen bonding interaction. Computational studies provided strong support for the experimental observation.
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http://dx.doi.org/10.1021/jo050753+ | DOI Listing |
Food Sci Nutr
January 2025
Technical University of Munich, TUM School of Life Sciences, Chair of Brewing and Beverage Technology, Group Raw Material Based Brewing and Beverage Technology Freising Germany.
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December 2024
Department of Pharmacy, University of Naples Federico II, 80131 Napoli, Italy.
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View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
Hexaanionic cyclophosphazenate ligands [(RN)PN] provide versatile platforms for the assembly of multinuclear metal arrays due to their multiple coordination sites and highly flexible ligand core structure. This work investigates the impact of incrementally increasing the steric demand of the ligand periphery on the coordination behavior of ethylzinc arrays. It shows that the increased congestion around the ligand sites is alleviated by progressive condensation with the elimination of diethylzinc.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
January 2025
Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522, Japan.
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January 2025
Biochemistry Center Heidelberg, Heidelberg University, 69120 Heidelberg, Germany. Electronic address:
The data presented at the 9 International Murnau Conference on September 18-21, 2024, the largest recurring structural biology meeting in Central Europe, illustrated the thriving state of the structural biology community. This is largely attributed to the ground-breaking developments over the last decade, which were intensely discussed during the meeting.
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