5-iodo-ribofuranoside

This year has also seen approaches towards components of the anticancer natural product taxol from carbohydrate starting materials. Paquette and Bmley have used the 5-deoxy-5-iodo-ribofuranoside 61 as starting material for synthesis of 63, a precursor to the C ring of taxol. The carbohydrate-derived vinyl iodide 62 is transmetallated and the resulting vinyllithium reacts with terpenone 64 to afford 63 (Scheme 12). ... 

In our group, we have described the synthesis of nitroalkenes starting from iodo-glycosides via a novel tandem metallation-elimination-Henry reaction [60]. The reaction can be promoted either by the metal system zinc-indium or by n-BuLi, leading to different results in both cases. Thus, reaction of 5-iodo-ribofuranoside 3 with bromonitromethane in the presence of zinc (10 equivalents) and indium (1 equivalent) in THF/H2O 4 1 under sonication at 40°C, afforded a 5 4 mixture of nitrohexene 76 and bromonitrohexene 77, from which nitrohexene 76 was isolated in a 39% yield... 

SCHEME 3.27 Mechanism for the formation of l-nitro-6-hexenes 76 and 1-bromo-l-nilro-6-hexene 77 from 5-iodo-ribofuranoside 3. 

Methyl 5-deoxy-2,3-0-isopropylidene l3-T>-erythro-pent-4-enofurano-side (43). A solution of methyl 5-deoxy-5-iodo-2,3-0-isopropylidene-/ -D-ribofuranoside (42) (30) (1.0 grams) in pyridine (10 ml.) was shaken for 7 hours at room temperature with anhydrous silver fluoride (1.5 grams). Isolation of the product as described previously afforded the 4-ene (43) as a sirup (414 mg., 70%) which distilled at 40°C. (bath) at 0.1 mm. G.l.c. showed the presence of a major component (95%) together with 5% of another component which was not investigated. [ ]D21 + 26.3° (c, 2.3). Anal Calcd. for C9H1404 C, 58.05 H, 7.6. Found C, 57.9 H, 7.7. 

One of the earliest reported preparations of the requisite glycosidation precursor 5-deoxy-l,2,3-tri-0-acetyl-p-D-ribofuranoside (17) was published by Kissman and Baker in 1957.23 D-Ribose was heated at reflux in a methanol/acetone mixture in the presence of concentrated HCI to provide methyl 2,3-O-isopropylidene-D-ribofuranosidc (21), which was in turn converted to the corresponding 5-O-mesyl ribofuranoside 22 with methanesulfonyl chloride in pyridine in 63% yield. The sulfonate moiety of 22 was then displaced with sodium iodide in refluxing DMF to provide 5-deoxy-5-iodo derivative 23 in 76% yield on a multigram scale. Reductive dehalogenation of 23 was accomplished under heterogeneous catalytic hydrogenation conditions to provide the reduced 2,3-0-protected intermediate 24 in 56% yield, which was subjected to hydrolysis conditions in... 

For carbohydrates, 5-phosphonylated-D-ribofuranoside is prepared by a Michaelis-Arbuzov reaction from the 5-iodo derivative and then deprotected to give the corresponding aldehyde. ... 

Orthoesters are converted into esters with TMS-I. The dimethyl acetal of formaldehyde, methylal, affords iodomethyl methyl ether in good yield (eq 12) 7a (in presence of alcohols, MOM ethers are formed). 7b a-Acyloxy ethers also furnish the iodo ethers, e.g. the protected 8-acetyl ribofuranoside gave the a-iodide which was used in the synthesis of various nucleosides in good yield (eq 13). Aminals are similarly converted into immonium salts, e.g. Eschenmoser s reagent, Dimethyl(methylene)ammonium Iodide, in good yield. ... 

Me glycoside, 2,3-0 benzylidene Methyl 2,3 0 benzylidene 5 deoxy-5-iodo fi i> ribofuranoside [33208-38-7]... 

Me glycoside, 2,3-O-isopropylidene Methyl 5-deoxy-5-iodo-2,3-0-isopropylidene-fi-D-ribofuranoside [38838-06-1]... 

Methyl 4,6-0-benzylidene-3-deoxy-a-D-/Areo-hexopyranosid-2-ulose, D-216 Methyl 4,6-0-benzylidene-3-deoxy-p-i>i eo-hexopyranosid-2-ulose, D-216 Methyl 4,6-0-benzylidene-3-deoxy-3-iodo-p-D-allopyranoside, D-243 Methyl 3,4-0-(R)-benzylidene-2-deoxy-2-iodo-a-i> tropyranoside, D-246 Methyl 3,4-0-(5 )-benzylidene-2-deoxy-2-iodo-a-i>altropyranoside, D-246 Methyl 4,6-0-benzylidene-2-deoxy-2-iodo-a-D-altropyranoside, D-246 Methyl 4,6-0-benzylidene-2-deoxy-2-iodo-p-D-altropyranoside, D-246 Methyl 4,6-0-benzylidene-3-deoxy-3-iodo-a-i>altropyranoside, D-247 Methyl 4,6-0-benzylidene-2-deoxy-2-iodo-a-i>idopyranoside, D-261 Methyl 2,3-0-benzylidene-5-deoxy-5-iodo-p-D-ribofuranoside, D-272 Methyl 4,6-0-benzylidene-3-deoxy-3-iodo-2-0-tosyl-a-i>altropyranoside, D-247... 

Methyl 5-(leoxy-5-iodo-2,3-6 -isopropylidene-p-D-ribofuranoside, D-272 Methyl 2-deoxy-2-iodo-a-D-mannopyranoside, D-265 Methyl 2-deoxy-2-iodo-p-D-mannopyranoside, D-265 Methyl 6-deoxy-6-iodo-a-D-mannopyranoside, D-266 Methyl 6-deoxy-6-iodo-3-D-mannopyranoside, D-266 Methyl 3-deoxy-3-iodo-4-0-methyl-p-L-xylopyranoside, D-280 Methyl 2-deoxy-2-iodo-a-D-talopyranoside, D-275 Methyl 6-deoxy-3,4-0-isopropylidenegalactopyranoside, M-198 Methyl 6-deoxy-2,3-0-isopropylidene-a-D-gulopyranoside, D-146 Methyl 6-deoxy-2,3-0-isopropylidene-p-L-gu/o -heptofuranoside, D-162 Methyl 6-deoxy-2,3-0-isopropylidene-a-D-wa wo -heptofuranoside, D-164 Methyl 6-deoxy-2,3-0-isopropylidene-a-L-fa/o -heptofuranoside, D-165 Methyl 6-deoxy-2,3-0-isopropylidene-a-D-/yxo-hex-5-enopyranoside, D-176 Methyl 5-deoxy-2,3-0 -isopropylidene-p-D-rj6o -hexofuranoside, D-207 Methyl 2-deoxy-3,4-0 -isopropylidene-a-D-/ xo -hexopyranoside, D-202 Methyl 6-deoxy-2,3-0-isopropylidene-a-D-/ xo-hexopyranosid-4-ulose, D-190... 

Methyl 3-acetamido-2,5-di-0-acetyl-3-deoxy-a-D-ribofuranoside, A-330 Methyl 3-acetamido-2,5-di-0-acetyl-3-deoxy-p-D-ribofuranoside, A-330 Methyl 3-acetamido-2,4-di-0-acetyl-3-deoxy-a-D-ribopyranoside, A-330 Methyl 5-amino-5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, A-332 Methyl 3-amino-3-deoxy-p-D-ribofuranoside, SCI, A-330 Methyl 5-0-benzoyl-2,3-0-benzylidene-p-D-ribofuranoside, M-208 Methyl 5-0-benzoyl-2,3-di-0-tosyl-p-D-ribofuranoside, M-208 Methyl 5-0-benzoyl-2,3-0-methylene-p-D-ribofuranoside, M-208 Methyl 2,3-0-benzylidene-5-deoxy-5-iodo-p-D-ribofuranoside, D-272 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-a-D-ribofuranoside, B-93 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, B-93 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-L-ribofuranoside, B-93 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-DL-ribofuranoside, B-93 Methyl 5-chloro-5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, C-100 Methyl 5-chloro-5-deoxy-a-D-ribofuranoside, C-100 Methyl 5-chloro-5-deoxy-p-D-ribofuranoside, C-100 Methyl 5-deoxy-5-iodo-2,3-0-isopropylidene-p-D-ribofuranoside, D-272 Methyl 5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, D-362 Methyl 5-deoxy-D-ribofuranoside, D-362... 

Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-p-D-ribopyranoside, D-270 Methyl 3,5-di-0-benzoyl-2-bromo-2-deoxy-a-D-ribofuranoside, B-92 Methyl 2,3-di-0-benzoyl-5-bromo-5-deoxy-p-D-ribofuranoside, B-93 Methyl 2,4-di-0-benzoyl-3-deoxy-3-iodo-p-L-ribopyranoside, D-271 Methyl 3,5-di-0-benzoyl-2-0-methyl-p-D-ribofuranoside, M-208 Methyl 3,5-di-O-benzoyl-p-D-ribofuranoside, M-208 Methyl 3,5-di-O-benzyl-a-D-ribofuranoside, M-208 Methyl 3,4-dichloro-3,4-dideoxy-p-D-ribopyranoside, D-545 Methyl 2-C-formyl-3,4-0-isopropylidene-p-D-ribopyranoside, F-23 Methyl 3,4-0-isopropylidene-2-0-methyl-p-D-ribopyranoside, M-209 Methyl 2,3-0-isopropylidene-5-5 -methyl-5-thio-p-D-ribofuranoside, T-91 Methyl 2,3-0-isopropylidene-p-D-ribofuranoside, 1-74 Methyl 2,3-0-isopropylidene-p-L-ribofuranoside, 1-74 Methyl 2,3-0-isopropylidene-p-D-ribopyranoside, M-209 Methyl 3,4-0-isopropylidene-p-D-ribopyranoside, M-209 Methyl 2,3-0-isopropylidene-5-thio-p-D-ribofuranoside, T-91 Methyl 2,3-0-isopropylidene-5-thio-p-D-ribopyranoside, T-91 Methyl 3,4-0-isopropylidene-5-thio-p-D-ribopyranoside, T-91... 

Methyl 3,5-di-0-acetyl-2-bromo-2-deoxy-a-D-arabinofuranoside, B-62 Methyl 3,5-di-0-acetyl-2-bromo-2-deoxy-p-D-arabinofuranoside, B-62 Methyl 3,4-di-0-acetyl-2-bromo-2-deoxy-a-D-lyxopyranoside, B-82 Methyl 3,5-di-0-acetyl-2-chloro-2-deoxy-a-D-arabinofuranoside, C-74 Methyl 3,5-di-0-acetyl-2-chloro-2-deoxy-p-D-arabinofuranoside, C-74 Methyl 3,4-di-0-acetyl-2-chloro-2-deoxy-a-D-arabinopyranoside, C-74 Methyl 3,4-di-0-acetyl-2-chloro-2-deoxy-a-D-lyxopyranoside, C-95 Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-a-D-ar inopyranoside, D-249 Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-a-L-arabinopyranoside, D-249 Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-a-D-lyxopyranoside, D-263 Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-a-L-lyxopyranoside, D-263 Methyl 3,4-di-0-acetyl-2-deoxy-2-iodo-p-D-ribopyranoside, D-270 Methyl 3,5-di-0-benzoyl-2-bromo-2-deoxy-p-D-arabinofuranoside, B-62 Methyl 3,5-di-0-benzoyl-2-bromo-2-deoxy-a-D-ribofuranoside, B-92 Methyl 3,4-di-0-benzoyl-2-deoxy-2-fluoro-D-ribofuranoside, D-106 Methyl 3,4-di-0-benzoyl-2-deoxy-2-fluoro-D-ribopyranoside, D-106 Methyl 3,5-di-0-benzyl-2-chloro-2-deoxy-a-D-arabinofuranoside, C-74 Methyl 2,4-dibromo-2,4-dideoxy-L-erythronate, D-541 Methyl 2,4-dibromo-2,4-dideoxy-D-threonate, D-541 Methyl 2,4-dibromo-2,4-dideoxy-L-threonate, D-541 Methyl 2,6-dideoxy-2-fluoro-p-L-talopyranoside, D-569 Methyl 3,4,6-txi-0-acetyl-2-bromo-2-deoxy-a-D-galactopyranoside, B-70 Methyl 3,4,6-txi-0-acetyl-2-bromo-2-deoxy-p-i>galactopyranoside, B-70 Methyl 3,4,6-txi-0-acetyl-2-bromo-2-deoxy-a-i>mannopyraiioside, B-87... 

Methyl 2,3-0-benzylidene-5-deoxy-5-iodo-p-D-ribofuranoside, D-272 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-D-ribofuranoside, B-93 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-L-ribofuranoside, B-93 Methyl 5-bromo-5-deoxy-2,3-0-isopropylidene-p-DL-ribofuranoside,... 

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