ISSN:
0170-2041
Keywords:
Sialic acids
;
Phase-transfer catalysis
;
N-Ketosides
;
Carbohydrates
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
α-N-Ketosides of N-acetylneuraminic acid (Neu5Ac) can be synthesized by using azide and thiocyanate salt as aglycone under conditions of phase-transfer catalysis (PTC). The catalytic hydrogenation of the 2-α-azido ketoside 3 leads to the 2-α-amino ketoside 4 in good yield. This 2-α-amino ketoside 4 can be transformed into the 2-α-acetamido ketoside 5 and the 2-α-benzoylamido ketoside 6. Zemplén deacetylation and saponification give the corresponding 2-N-acyl ketosides 7 and 8, which cannot be hydrolyzed by neuraminidase (Clostridium perfringens). Treatment of the 2-α-amino ketoside 4 with p-nitrobenzaldehyde results in the formation of p-nitrobenzylideneamine 9. Based on the strict stereoselectivity of the PTC glycosidation reaction with sialic acid derivatives and the exclusive formation of the N-ketoside 10 in the reaction with potassium thiocyanate, a model of the mechanism of the PTC glycosidation procedure with sialic acid derivatives has been evaluated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1992199201131
