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A Practical One‐Step Synthesis of 1,2‐Oxazoline Derivatives from Unprotected Sugars and Its Application to Chemoenzymatic β ‐ N ‐Acetylglucosaminidation of Disialo‐oligosaccharide
Author(s) -
Noguchi Masato,
Fujieda Tsukasa,
Huang Wei Chun,
Ishihara Masaki,
Kobayashi Atsushi,
Shoda Shinichiro
Publication year - 2012
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200414
Subject(s) - chemistry , oxazoline , moiety , oligosaccharide , yield (engineering) , glycosylation , glycosyl , anomer , stereochemistry , intramolecular force , chloride , sugar , glycosyl donor , organic chemistry , catalysis , biochemistry , materials science , metallurgy
A facile and practical method for synthesis of sugar oxazolines (=dihydrooxazoles) from the corresponding N ‐acetyl‐2‐amino sugars has been developed by using 2‐chloro‐1,3‐dimethyl‐1 H ‐benzimidazol‐3‐ium chloride (CDMBI) as a dehydrative condensing agent. The intramolecular dehydrative reaction between the 2‐acetamido group and the anomeric OH group of unprotected N ‐acetyl‐2‐amino sugars took place smoothly in H 2 O, leading to the formation of a 1,2‐oxazoline (=4,5‐dihydrooxazole) moiety in good yield. Since the reaction proceeds in H 2 O without using any protecting groups, the resulting oxazolines can be utilized as effective glycosyl donors for the subsequent enzymatic glycosylation. We have successfully demonstrated a highly efficient chemoenzymatic transglycosylation of a disialo‐oligosaccharide moiety to p ‐nitrophenyl N ‐acetylglucosaminide catalyzed by a mutant endo‐ N ‐acetylglucosaminidase without isolating disialo‐oligosaccharide oxazoline as synthetic intermediate.