ISSN:
1434-4475
Schlagwort(e):
Acetolysis of methyl-9-O-acetyl-5-acetylamino-7,8-anhydro-4-O-(tBDMSi)-3,5-dideoxy-β-D-(andL)-glycero-D-galacto-2-nonulosidonic acid methylester, methyl-9-O-acetyl-5-acetylamino-7,8-anhydro-4-O-(tBDMSi)-3,5-dideoxy-β-D-glycero-L-altro-2-nonulosidonic acid methylester
;
Configurational changes of sialic acid
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract From methyl-5-acetylamino-7,8-anhydro-4,9-O-bis-(t-butyldimethylsilyl)-3,5-dideoxy-β-D-glycero-D-galacto-2-nonulopyranosidonic acid methylester (1) the derivatives1 a and1 b were obtained by removing the 9-O-(t-butyldimethylsilyl)group withBu 4NF, followed by acetylation. Treatment of1 b with 80% acetic acid and acetanhydride/pyridine yields the 8-epi-N-acetylneuraminic acid derivative2 a and the 7-epi-N-acetylneuraminic acid derivative3 a in a ratio of 3:1 (Scheme 1). The structure elucidation of2 b was achieved by converting2 b via the 4,9-bis-O-(tBDMSi)-8-O-tosyl-derivative2 d into the epoxide1 (Scheme 2). Using the same sequence the epoxides4 and5 were transformed into theN-acetylneuraminic acid derivative6 a and the 7,8-bis-epi-N-acetylneuraminic acid derivative7 a (Scheme 3). After treatment with sodium hydroxide and 0.025m HCl and Dowex 50 H+ the 8-epi-, 7-epi- and 7,8-bis-epi-N-acetylneuraminic acids2,3, and7 were obtained. These three compounds were tested withCMP-N-acetylneuraminic acid synthetase.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00798282
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