ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Glycosidation of Steroids and Cardenolide Steroids with 2-Alkylthio- and 2-Alkylthio-6-deoxy-hexopyranosyl BromidesThe 3-O-methylated 2-S-benzyl-2-thio-altropyranosyl bromide 3 reacts with cholesterol to yield α- and β-glycosides (4 and 6), by hydrogenation of which cholesterol-2-deoxy-D-ribo-hexopyranoside (5) is obtained. The allo-epoxide 7 is opened by sodium bezylmercaptide to give a 1:1 mixture of 2-S-benzyl-2-thio-altro-(8) and 3-S-benzyl-3-thio-gluco compound (9) which can be hydrolysed by acid. The glycosyl bromide 16 can be obtained from the anomeric mixture of the acetates of the 2-thio-altro compound 14 + 15. By glycosidation with cholesterol and digitoxigenine in addition to the formation of some 2-thio-glycal 17 the anomeric glycosides 20/21 and 18/19, resp., are obtained. Their reduction with Raney nickel gives cholesterol- or anhydrodigitoxigenine-3-(2,6-dideoxy-α-and -β-D-ribo-hexopyranosides) 22 + 23 or 24 + 25, respectively. Changes in the aglycon are noted with the digitoxigenine derivative.
Notes:
3-O-Methyliertes 2-S-Benzyl-2-thio-altropyranosylbromid 3 reagiert mit Cholesterin zu α- und β-Glycosiden (4 und 6), deren Hydrierung Cholesterin-2-desoxy-D-ribo-hexopyranosid (5) liefert. Das allo-Epoxid 7 wird mit Natrium-benzylmercaptid zu einem 1:1-Gemisch aus 2-S-Benzyl-2-thio-altro-(8) und 3-S-Benzyl-3-thio-gluco-Verbindung (9) geöffnet, deren saure Hydrolyse gelingt. Aus dem Anomerengemisch der Acetate der 2-Thio-altro-Verbindungen 14 + 15 kann das Glycosylbromid 16 gewonnen werden. Dessen Glycosidierung mit Cholesterin und Digitoxigenin führt neben der Bildung des 2-Thio-glycals 17 zu den anomeren Glycosiden 20/21 bzw. 18/19, deren Reduktion mit Raney-Nickel Cholesterin- bzw. Anhydrodigitoxigenin-3-(2,6-didesoxy-α- und -β-D-ribo-hexopyranoside) 22 + 23 bzw. 24 + 25 ergibt. Beim Digitoxigenin-Derivat treten Veränderungen im Aglycon auf.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19771100820
Permalink
