A convenient new pathway for stereospecific epimerization of monosaccharide moieties in disaccharides
✍ Scribed by Ralf Miethchen; Daniel Rentsch; Michael Frank; András Lipták
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 429 KB
- Volume
- 281
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
The disaccharides benzyl 4,6-O-benzylidene-2-O-alpha-D-mannopyranosyl-beta- D-glucopyranoside (2), 6-O-beta-D-galactopyranosyl-1,2:3,4-di-O-isopropylidene-alpha-D- galactopyranose (4), and phenyl 4-O-beta-D-galactopyranosyl-1-thio-beta-D-glucopyranoside (7) were selectively acetalated with chloral-dicyclohexylcarbodiimide in a nonclassical pathway. During acetalation, the D-mannopyranosyl moiety of the disaccharide 2 and the unprotected beta-D-galactopyranosyl moieties of 4 and 7 were epimerized at their 3-positions, generating D-altro- and D-gulo-pyranosyl moieties, respectively.