Selective 3-O-allylation and 3-O-benzylation of methyl α-d-manno-, α-l-rhamno- and β-l-fuco-pyranoside
✍ Scribed by Guangbin Yang; Fanzuo Kong; Shuhua Zhou
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 250 KB
- Volume
- 211
- Category
- Article
- ISSN
- 0008-6215
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📜 SIMILAR VOLUMES
Condensation of 2,4-di-O-acetyl-3,6-di-O-methyl-a-~glucopyranosyl bromide with either ally1 or benxyl2,4-di-0-methyl-cu+rhamnopyranoside in the presence of mercuric cyanide, followed by 0-deacetylation, gave the title oligosaccharides in excellent yields.
The title branched-trisaccharide derivatives (9 and 13) have been synthesised from methyl 2,3-O-(2-nitrobenzylidene)-a-L-rhamnopyranoside (2) using the 2nitrobenzylidene residue as a temporary blocking-group. Condensation of 2 with methyl (2,3,4-tri-O-acetyl-a-D-glucopyranosyl bromide)uronate afford
D-Ribose was converted into methyl 5-O-benzyl-beta-D-ribofuranoside and this, on tin-mediated allylation, gave a mixture of the 2-O-allyl and 3-O-allyl derivatives which were separated by chromatography. The more polar isomer was characterised as the 3-O-allyl derivative after conversion via 3-O-all