Synthesis of cardenolide glycosides and putative biosynthetic precursors of cardenolide glycosides.
A rapid and efficient procedure for glycosylation of steroids was established using a modified Koenigs-Knorr procedure. Peracetylated beta-glycosides were synthesized by reaction of cardenolides, various pregnanes and 23-nor-5,20(22)E-choldienic acid at room temperature with the peracetylated 1-bromo derivatives of D-glucose, D-galactose, D-fucose and cellobiose. Subsequent deprotection was performed by alkaline hydrolysis with sodium methoxide. Structures of the respective glycosides were established by NMR techniques. The complete protocol was shown to be non-destructive at all stages to the sugar moiety and the steroidal nucleus. The gamma-unsaturated lactone ring of the cardenolides was shown to remain intact and no formation of C-14 unsaturated compounds was observed.
Luta
M
M
Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Botanik und Pharmazeutische Biologie, Germany.
Hensel
A
A
Kreis
W
W
D002298:Cardenolides / Q000138:chemical synthesis* / Q000378:metabolism; D006027:Glycosides / Q000096:biosynthesis / Q000138:chemical synthesis*; D006031:Glycosylation; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy
D002298:Cardenolides; D006027:Glycosides