Přejít k obsahu


Conformation study of a-ring in 19β,28-epoxy-2-fluoro-18α-oleananes

Citace: [] TIŠLEROVÁ, I., RICHTR, V., KLINOT, J. Conformation study of a-ring in 19β,28-epoxy-2-fluoro-18α-oleananes. Collection of Czechoslovak Chemical Communications, 2006, roč. 71, č. 3, s. 368-386. ISSN: 0010-0765
Druh: ČLÁNEK
Jazyk publikace: eng
Anglický název: Conformation study of a-ring in 19β,28-epoxy-2-fluoro-18α-oleananes
Rok vydání: 2006
Autoři: Iva Tišlerová , Václav Richtr , Jiří Klinot
Abstrakt CZ: Byla připravena řada triterpenoidních 2-flouro substituentů 19ß,28-epoxy-18beta-oleananu. Podrobnou NMR analýzou byla určena konfigurace substituentů.
Abstrakt EN: A series of 2-fluoro-substituted 19ß,28-epoxy-18α-oleanane triterpenoids was prepared. Detailed NMR analysis (1H, 13C, 19F) was used for independent determination of the configuration of substituents. Conformation of the A-ring was derived from coupling constants J(H,H), J(F,H), J(F,C) and NOE-contacts observed in 2D-H,H-NOESY spectra. It was found that A-ring in all 2α-fluoro derivatives and 2ß-fluoro-3ß-OR derivatives and adopts chair-form, while in 2ß-fluoro ketone a boat-form is preferred. The chair–boat equilibrium of A-ring was found in 2ß-fluoro-3.-OR derivatives.
Klíčová slova

Zpět

Patička