Synthesis of rhamnosylated diosgenyl glucosides as mimetics of cytostatic steroidal saponins from Ornithogalum saindersiae and Galtonia candicans.
The synthesis of mimetic of the steroid saponins 1 and 2 was investigated. As a substitute for the complex 22-homo-23-nor-steroid moieties A and B in 1 and 2 diosgenin was introduced. The silyl protected thioorthoester 20 was successfully employed for glucosylation. After selective 2--deacetylation, the glucosylated diosgenyl acceptor 23 was rhamnosylated. The 4---methoxybenzoylated donor 12 gave only minor yields. By using the tri--benzoyl protected donor 15 the [small alpha]--rhamnopyranosyl-(1[rightward arrow]2)-[small beta]--glucopyranosyl-(1[rightward arrow]3[small beta])-diosgenin derivative 25 was obtained.
Suhr
Rene
R
Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany.
Pfefferkorn
Pascal
P
Weingarten
Saskia
S
Thiem
Joachim
J
D002236:Carbohydrate Conformation; D004144:Diosgenin / Q000737:chemistry*; D005960:Glucosides / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D019668:Liliaceae / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D012503:Saponins / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D005960:Glucosides; D012503:Saponins; D004144:Diosgenin