Anthracycline oligosaccharides: facile stereoselective synthesis of 2,6-dideoxy-α-l-lyxo-hexopyranosides
✍ Scribed by Cenek Kolar; Günther Kneissl; Heinz Wolf; Thomas Kämpchen
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 438 KB
- Volume
- 208
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Glycosylation of benzyl-2,3,6-trideoxy-3-trifluoroacetamido-alpha-L-lyxo-h exopyranoside (6) with 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-lyxo-hex-1-enitol (1) or 4-O-acetyl-1,5-anhydro-3-O-benzyl-2,6-dideoxy-L-lyxo-hex-1-enit ol (2) in the presence of trimethylsilyl triflate/triethylamine gave alpha-(1----4)-linked disaccharide derivatives 7 and 8, respectively. In the presence of trimethylsilyl triflate only, 3,4-di-O-acetyl-1-O-tert-butyldimethylsilyl-2,6-dideoxy-beta-L-lyxo++ +-hexopyranose (3) and 6 gave mainly 7. Condensation of 1 or 2 with 9, obtained by O-deacylation of 8, afforded benzyl [O-(3,4-di-O-acetyl-2,6-dideoxy-alpha-L-lyso-hexopyranosyl)-(1----4)-O-( 3-O-benzyl-2,6-dideoxy-2,6-alpha-L-hexopyranosyl)-(1----4)-(2,3,6-tri deo xy-3-trifluoroacetamido-alpha-L-lyxo-hexopyranoside)] (11) and its 3''-benzyl analogue 12, respectively.
📜 SIMILAR VOLUMES
We have recently described' the reductive desulfonyloxylation of some secondary p-toluenesulfonates of glycosides by lithium triethylborohydride (Super Hydride@', LTBH), which afforded high yields of deoxy sugars. The glycosides used were 4,6-0-benzylidenated glycopyranoside 2-and 3-tosylates, and t
The title glycosides were synthesised from D-glUCOSe, via the common intermediate methyl 2-acetamido-4-O-benzoyld-bromo-2,3,6-trideoxy-a-D-ribohexopyranoside . \*To whom enquiries should be addressed. \*\*The overall efficiency of this procedure can be improved by using a phase-transfer process' in