Sequential tritylation, benzoylation, and detritylation of methyl 3-deoxy-3fluoro-AD-galactop~~oside gave crystalline methyl 2,4-di-O-benzoyl-3-deoxy-3-~uoro-ED-gala~opyr~oside (9), which was used as the initial nucleophile in the synthesis of the target otigosaccha~de (16). Treatment of 9 with 2,3,
Synthesis and N.M.R. spectra of methyl 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro-α- and β-d-glucopyranosides
✍ Scribed by Pavol Kováč; Herman J.C. Yeh; Cornelis P.J. Glaudemans
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 857 KB
- Volume
- 169
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Methyl 3-deoxy-3-fluoro-alpha- and beta-D-glucopyranosides and alpha- and beta-D-glucofuranosides were prepared by methanolysis of 3-deoxy-3-fluoro-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose. Crystalline 3,4,6-tri-O-acetyl-2-deoxy-2-fluoro-alpha-D-glucopyranosyl chloride (2) and the corresponding glycosyl bromide (3) were prepared from 1,3,4,6-tetra-O-acetyl-2-deoxy-2-fluoro-beta-D-glucopyranose (1). Reaction of 2 with methanol under the conditions of both silver triflate- and silver perchlorate-catalyzed glycosylation showed remarkable lack of stereoselectivity for the formation of the corresponding methyl alpha-glycoside, despite the presence at C-2 of the fluorine functionality presumably not capable of neighboring-group participation. Pure methyl 2-deoxy-2-fluoro-alpha- and beta-D-glucopyranosides were obtained by fractional crystallization from the mixture formed by methanolysis of 1. The structure of these substances as well as of several other derivatives of 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro-D-glucose were verified by n.m.r. (1H, 13C, and 19F) spectroscopy.
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## Abstract Convergent syntheses of the 9‐(3‐X‐2,3‐dideoxy‐2‐fluoro‐__β__‐D‐ribofuranosyl)adenines **5** (X=N~3~) and **7** (X=NH~2~), as well as of their respective __α__‐anomers **6** and **8**, are described, using methyl 2‐azido‐5‐__O__‐benzoyl‐2,3‐dideoxy‐2‐fluoro‐__β__‐D‐ribofuranoside (**4**