ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Syntheses of Biologically Important Carbohydrates, 21 Asymmetrically Induced Synthesis of Amino Sugars: Methyl 4-O-Acetyl-3-acetylamino-2,3,6-trideoxy-α-D-xylo-hexopyranosidetrans-4-Hexenal-((2R, 3R)tartaric acid dimethyl ester acetal) (6) is aminated in allylic position with metallic selenium and chloramine-T yielding the easily separable 3-tosylamino derivatives with D-(7) and L-glycero-configuration (8) at C-3. 7 is hydroxylated with osmium tetroxide giving the 4,5-dihydroxy-3-tosylamino-D-xylo-hexanal acetal 9 with high selectivity. By splitting off the carbonyl protecting group from 9 with HCl in methanol methyl 2,3,6-trideoxy-3-tosylamino-hexoside 11 is obtained. Detosylation of 11 with sodium in liquid ammonia and peracetylation gives methyl 4-O-acetyl-3-acetylamino-2,3,6-trideoxyhexoside 13 with D-configuration. The constitution of 11 and 13 is proved by mass spectrometry and the α-xylo-configuration is determined by means of the 1H-NMR spectra.
Notes:
trans-4-Hexenal-((2R, 3R)-weinsäure-dimethylester-acetal) (6) liefert nach allylischer Aminierung mit metallischem Selen und Chloramin-T die gut trennbaren 3-Tosylamino-Derivate mit D- (7) und L-glycero-Konfiguration (8) an C-3. 7 wird mit Osmiumtetroxid hoch selektiv zum 4,5-Dihydroxy-3-tosylamino-D-xylo-hexanal-acetal 9 hydroxyliert, aus dem durch Abspaltung der Carbonylschutzgruppe mit HCl in Methanol das Methyl-2,3,6-tridesoxy-3-tosylaminohexosid 11 entsteht. Dessen Detosylierung mit Natrium in flüssigem Ammoniak führt nach Peracetylierung zum D-konfigurierten Methyl-4-O-acetyl-3-acetylamino-2,3,6-tridesoxyhexosid 13, dessen Konstitution durch Massenspektrometrie und dessen α-xylo-Konfiguration durch 1H-NMR-Untersuchungen bewiesen wird.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19801130438
