- Efficient one-pot per-: O -acetylation-thioglycosidation of native sugars, 4,6- O -arylidenation and one-pot 4,6- O -benzylidenation-acetylation of S -/ O -glycosides catalyzed by Mg(OTf)2
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A sequential one-pot per-O-acetylation-S-/O-glycosidation of native mono and disaccharides under solvent free conditions using 0.5 mole% of Mg(OTf)2 as a non-hygroscopic, recyclable catalyst is reported. Regioselective 4,6-O-arylidenation of glycosides and thioglycosides with benzaldehyde or p-methoxybenzaldehyde dimethyl acetal is catalyzed by 10 mole% of Mg(OTf)2 to produce the corresponding 4,6-O-arylidenated product in high yields. Mg(OTf)2 can also mediate sequential one-pot benzylidenation-acetylation of mono and disaccharide based glycosides and thioglycosides in high yield.
- Mukherjee, Mana Mohan,Basu, Nabamita,Chaudhury, Aritra,Ghosh, Rina
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p. 109301 - 109314
(2016/11/30)
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- Synthesis of an aminooxy derivative of the trisaccharide globotriose Gb3
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The synthesis of α-aminooxy trisaccharide moiety [α-d-Gal-(1,4)-β-d-Gal-(1,4)-β-d-Glc-α-aminooxy], related to the cell surface globotriaosylceramide (Gb3) receptor of the B subunit of the AB5 Shiga toxin of Shigella dysenteriae, has been carrie
- Ghosh, Samir,Andreana, Peter R.
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p. 381 - 394
(2015/04/14)
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- FeCl3 mediated arylidenation of carbohydrates
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Glycosides and thioglycosides based on monosaccharides in reaction with benzaldehyde dimethylacetal or p-methoxybenzaldehyde dimethyl acetal undergo FeCl3-catalyzed (20 mol %) regioselective 4,6-O-arylidenation producing the corresponding acetals in high yields. FeCl3 also mediates acetalation of glycosides and thioglycosides of cellobiose, maltose, and lactose affording the corresponding 4′,6′-O-benzylidene acetals, which were isolated after their acetylation in situ with acetic anhydride and pyridine. The combined yields (two steps) of these final products are also high (61-84%). The procedure is applicable to a wide variety of functional groups including -OBn.
- Basu, Nabamita,Maity, Sajal K.,Roy, Soumik,Singha, Shuvendu,Ghosh, Rina
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scheme or table
p. 534 - 539
(2011/04/27)
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- A facile protocol for direct conversion of unprotected sugars into phenyl 4,6-O-benzylidene-per-O-acetylated-1,2-trans-thioglycosides
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A short and practical methodology for conversion of unprotected D-glucose, maltose, cellobiose and lactose into the corresponding phenyl 4,6-O-benzylidine-per-O-acetylated-1,2-trans-thioglycosides is described. The protocol is based on the execution of five reaction steps (bromoacetylation, thiophenolysis under phase transfer catalysis conditions, deacetylation, benzylidenation and acetylation) in one continuous procedure and provides a fast access to the title compounds as pure crystalline products without chromatographic purification.
- Larsen, Kim,Olsen, Carl Erik,Motawia, Mohammed Saddik
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p. 199 - 202
(2007/10/03)
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- HYDROGENOLYSIS OF THE BENZYLIDENE ACETALS OF THIOGLYCOSIDES WITH THE LiAlH4-AlCl3 REAGENT. SYNTHESIS OF PARTIALLY BENZYLATED THIOGLYCOSIDE DERIVATIVES
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Reductive hydrogenolysis of phenyl 2,3-di-O-benzyl-4,6-O-benzylidene-1-thio-β-D-gluco- (4) and -galactopyranoside (8) and phenyl 2,3,6,2',3'-penta-O-benzyl-4',6'-O-benzylidene-1-thio-β-cellobioside (15) with the LiAlH4-AlCl3 reagent resulted in the corres
- Liptak, A.,Jodal, I.,Harangi, J.,Nanasi, P.
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p. 415 - 422
(2007/10/02)
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