N-Glycosidation of D-arabino-hex-2-ulosonic acid.
Two approaches to N-functionalized D-arabino-hex-2-ulosonic acid derivatives were established by nucleophilic substitution of methyl (3,4,5-tri-O-acetyl-beta-D-arabino-hex-2-ulopyranosyl)onate bromide (1). Reaction of 1 with amino compounds in the presence of mercury(II) cyanide led to the 2,3-cis configured beta-D-arabino N-glycosides. On the other hand, the reaction of bromide 1 with azide, followed by catalytic hydrogenation led to 2,3-trans alpha-D-arabino glycosyl amine methyl 3,4,5-tri-O-acetyl-2-amino-alpha-D-arabino-hex-2-ulopyranosonate, which was easily rearranged to the thermodynamically more stable beta-D-arabino N-acetyl derivative methyl 4,5-di-O-acetyl-2-acetylamino-3-hydroxy-beta-D-arabino-hex-2-ulopyranosonate. The assignment of configuration of the tertiary anomeric centre and conformation of all products was based on 1H NMR H,H coupling constants and NOE difference experiments.
Andersch
J
J
Institut für Organische Chemie der Universität Leipzig, Germany. andersch@kemi.aau.dk
Hennig
L
L
Wilde
H
H
D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry; D007661:Ketoses / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013400:Sugar Acids / Q000138:chemical synthesis* / Q000737:chemistry
D006027:Glycosides; D007661:Ketoses; D013400:Sugar Acids; C421205:arabino-hex-2-ulosonic acid