- Studies on carbohydrates X. A new method for the preparation of isopropylidene saccharides
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Cabohydrates reacting with acetone in the presence of molecular sieve and p-toluene sulfonic acid provided a simple, convenient, high yield and good selective process for preparation of isopropylidene carbohydrates.
- He,Li,Li,Liu,Qiu,Cai
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p. 2653 - 2658
(2007/10/02)
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- DIFFERENT REACTIVITIES OF ACETYLATED exo- AND endo-CYANOETHYLIDENE DERIVATIVES IN GLYCOSYLATION REACTIONS
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The condensation of acetylated 1-(endo-cyano)ethylidene derivatives having the D-gluco, D-xylo, and D-galacto configurations (2-6) with a primary (8) and a secondary (9) trityl derivative was more rapid than for the corrensponding exo-isomers.This difference in reactivity is explained on the basis of differences in conformation.
- Vicent, Cristina,Coteron, Jose-Miguel,Jimenez-Barbero, Jesus,Martin-Lomas, Manuel,Penades, Soledad
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p. 163 - 170
(2007/10/02)
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- Alternative synthesis and regioselective coupling of 1,6-anhydro-2-azido- and -2-phthalimido-2-deoxy-β-D-galactopyranose
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Easily accessible 1,6-anhydro-3,4-isopropylidene-β-D-galactopyranose has been converted in four steps (i.e., oxidation, reduction, triflation and Walden inversion with lithium azide or potassium phthalimide) into 1,6-anhydro-2-azido- or -2-phthalimido-2-deoxy-3,4-O-isopropylidene-β-D-galactopyranose.The 2-azido derivative, obtained after acidolysis of the isopropylidene group, could be coupled regioselectively at the hydroxyl group at C-4 with either 1,3,4,6-tetra-O-acetyl-2-phthalimido-2-deoxy-β-D-glucopyranose or 3,4,6-tri-O-acetyl-2-phthalimido-2-deoxy-α-D-glucopyranosyl bromide in the presence of the soluble catalyst, trimethylsilyl trifluoromethanesulphonate, or the insoluble catalyst, silver silicate.
- Kloosterman, M.,Hey, H. T. de,Wit, D. de,Boom, J. H. van
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p. 229 - 231
(2007/10/02)
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