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Synthesis of α‐N‐Ketosides of N ‐Acetylneuraminic Acid by Using Phase‐Transfer Catalysis
Author(s) -
Rothermel Jörg,
Weber Bernd,
Faillard Hans
Publication year - 1992
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1992199201131
Subject(s) - chemistry , catalysis , hydrolysis , sialic acid , salt (chemistry) , stereoselectivity , azide , yield (engineering) , medicinal chemistry , saponification , organic chemistry , stereochemistry , biochemistry , materials science , metallurgy
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.