Cucurbitane-type glycosides were isolated from tuber extracts of Ibervillea sonorae as the major components. Among the minor constituents the corresponding aglycones kinoin A and kinoin B and the tetramethylated 19-norpregnenedione kinoin C have been found. These compounds represent new natural products and the 2,3,6-trihydroxy-6-methyl-4-heptenyl-2 side chain at C-17 of three of these compounds is unprecedented among the known cucurbitanes as well as sterols. The structures were determined by spectroscopic methods in combination with chemical degradations and modifications. Among others, 22-epi-dihydrokinoin A was prepared. The NMR data of the 22-epimers differ characteristically and allow the establishment of the relative configurations of the vicinal hydroxyl groups at C-20 and C-22 in this series of compounds.
4, 9, Cucurbitaceae, Ibervillea sonorae (formerly Maximowiczia sonorae), root (tuber), cucurbitacins kinoin A and B, kinoin A and B glycosides, hexanorcucurbitacin kinoin C [3α, 16α-dihydroxy-4, 14-tetramethyl-(9β, 10α)-19-norpregn-5-ene-11, 20-dione]
Publication DOI: 10.1016/0031-9422(93)85535-YJournal NLM ID: 0151434Publisher: Elsevier
Institutions: Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Erlangen, Erlangen, Germany, Depto. de Quimica, ITESM, Campus Monterrey, Sucursal de Correos “J”, Monterrey, N.L., Mexico
Methods: 13C NMR, 1H NMR, EI-MS, IR, FAB-MS, TLC, HPLC, enzymatic digestion, CI-MS, acetylation analysis
Found