- Fast, mild, and convenient procedures for iodination and bromination of carbohydrates: reactions of organoboranes with iodine monochloride, sodium iodide, bromine, and bromine chloride
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5-6-Dideoxy-1,2-O-isopropylidene-3-O-methanesulfonyl-α-D-xylo-hexafuranosene-5 (1), reacts with BH3-THF to form the tris(glycosyl)borane (2) and with dicyclohexylborane to form the dicyclohexylglycosylborane (3).The iodination and bromination of 2 and 3 has been investigated using a variety of electrophiles.Iodination of either 2 or 3 with NaI-Chloramine-T/NaOAc is complete within one minute with high percentage uptake of iodine (70-90 percent) and recovery of the iodinated sugar (4).Bromination of 2 in 15 minutes with NaBr-Chloramine-T permits a high percentage uptake of bromine (75 percent), and bromination of 3 in 15 minutes with Br2/NaOAc gives the brominated sugar (5) with a reasonably good yield (60 percent) with respect to the starting material (1).
- Hall, Laurance D.,Neeser, Jean-Richard
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- SYNTHETIC METHODS FOR THE LARGE SCALE PRODUCTION FROM GLUCOSE OF ANALOGS OF SPHINGOSINE, AZIDOSPHINGOSINE, CERAMIDES, LACTOSYL CERAMIDES, AND GLYCOSYL PHYTOSPHINGOSINE
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Synthetic methods are disclosed for the production from glucose of analogs of sphingosine, azidosphingosine, ceramides, lactosyl ceramides, glycosyl phytosphingosine, and enantiomeric derivatives of phytosphingosine and/or its homologues, for use in pharm
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Page 19; 39-40
(2010/02/05)
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- Synthesis of 3,5-anhydro-2-deoxy-1,4-glyconolactones by palladium(II)-catalyzed, regioselective oxycarbonylation of C5- and C6-enitols. ω-Homologation of aldoses to produce intermediates for C-glycoside/C-nucleoside synthesis
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The palladium(II)-catalyzed oxycarbonylation, known with alkenols and alkenediols, is studied with optically active 4-pentenitols (-triols) 1, 7 and 5-hexenitols (-tetrols) 12, 15, 18. Efficient routes for the substrates are provided, mostly from carbohyd
- Gracza,Hasenohrl,Stahl,Jager
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p. 1108 - 1118
(2007/10/02)
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