Showing papers on "Glucal published in 1995"
TL;DR: In this paper, the cyclopropano glycals derived from glucal and galactal have been transformed into 2-deoxy-2-vinyl mannosides and Galactosides, which are potentially valuable branched chain sugars.
35 citations
TL;DR: The 2- and 4-deoxy functions on the central mannose residue were introduced by displacement, using triiodoimidazole and triphenylphosphine, of a hydroxyl group by iodine on suitably protected derivatives followed by reduction of the resulting iodo analogues.
19 citations
18 citations
TL;DR: In this paper, a combination of glucal with aliphatic aldehydes leads to liquid crystals showing a monotropic SA phase, with aromatic p-alkoxy-substituted aldehyde to compounds with enantiotropic cholesteric and SA phases.
Abstract: Reaction of glucal 1 with alkoxybenzene leads after hydrogenation and deacetylation to β-C glycosides 4, which can be used as chiral compounds in the synthesis of chiral calamitic liquid crystals. The combination with aliphatic aldehydes leads to liquid crystals 5 showing a monotropic SA phase, with aromatic p-alkoxy-substituted aldehydes to compounds 6 with enantiotropic cholesteric and SA phases. Reaction with p-alkoxy-substituted phenylboronic acids gives liquid crystals 7 forming SA and ferroelectric SC* phases. They all exhibit a high twisting power and blue phases in contact preparation.
16 citations
TL;DR: In this article, an intramolecular cycloaddition of the nitrone derived from the glucal produces stereospecifically the isoxazolidine 9 which may be reductively cleaved to afford functionalised aminotetrahydrofuran polyols such as 20 and 23.
14 citations
TL;DR: In this article, a novel chemoenzymatic method for the preparation of glucal 4 in high yield is presented, which helps to gain further insight into the mechanism of the well-documented hypervalent iodine-promoted allylic oxidation of cyclic enol ethers.
Abstract: The reaction of 3,4-bis(O-tert-butyldimethylsilyl)-6-O-tosyl-D-glucal 4 with the Koser reagent [PhI(OH)OTs] unexpectedly afforded tetrahydrofurfural 6 as well as 2,3-anhydropyranose 7 as major products. This unprecedented, stereoselective transformation helps to gain further insight into the mechanism of the well-documented hypervalent iodine-promoted allylic oxidation of cyclic enol ethers. A novel chemoenzymatic method for the preparation of glucal 4 in high yield is presented.
11 citations
TL;DR: Hydrolysis of the glycal with hydrochloric acid led to 4-(5-hydroxymethylfuran-2-yl)imidazole, which contains both hydrophilic and hydrophobic aromatic heterocycles.
Abstract: Reaction of ribofuranosyl chlorides with 2 eq of 5-lithio-imidazole afforded 1-(5-imidazolyl)ribofuranoid glycals in good yields. Hydrolysis of the glycal (3) with hydrochloric acid led to 4-(5-hydroxymethylfuran-2-yl)imidazole (7), which contains both hydrophilic and hydrophobic aromatic heterocycles.
8 citations
4 citations
TL;DR: In this article, the reaction of ArSCI adducts of exo-glucal with O -and C -nucleophiles leads to a stereoselective preparation of ketopyranoside derivatives and 1, 1- gem -disubstituted C -glucosides, respectively.
4 citations
TL;DR: In this article, a short and facile entry to the 2, 3-unsaturated O-aryl glyco sides via microwave induced Ferrier rearrangement of acetylated glucal is reported.
Abstract: A short and facile entry to the 2, 3-unsaturated O-arylglyco sides via microwave induced Ferrier rearrangement of acetylated glucal is reported.
2 citations
Patent•
04 Apr 1995
TL;DR: An enzymatic process for the preparation of galactosyl β 1,3 glycal disaccharides such as Gal beta 1, 3Glucal, an intermediate useful in Lea preparation and an inhibitor of beta -galactosidase was disclosed in this paper.
Abstract: An enzymatic process is disclosed for the preparation of galactosyl beta 1,3glycal disaccharides such as Gal beta 1,3Glucal, an intermediate useful in Lea preparation and an inhibitor of beta -galactosidase. The process utilizes beta -galactosidase, an enzyme usually used for bond breaking, to form a bond between a galactoside and a glucal such as glycal, a 6-O-C1-C6 acylglucal or 6-O-C1-C6 acetylgalactal.
TL;DR: In this article, the reaction of ArSCI adducts of exo-glucal with O -and C -nucleophiles leads to a stereoselective preparation of ketopyranoside derivatives and 1, 1- gem -disubstituted C -glucosides, respectively.
Abstract: The reaction of ArSCI adducts of exo -glucal with O - and C -nucleophiles leads to a stereoselective preparation of ketopyranoside derivatives and 1,1- gem -disubstituted C -glucosides, respectively.
TL;DR: In the case of the 1,5-lactone compound, C 6 H 8 O 4, the lactone ring adopts a conformation between sofa and half-chair as discussed by the authors.
Abstract: In the 1,5-lactone compound, C 6 H 8 O 4 , the lactone ring adopts a conformation between sofa and half-chair. The five-membered ring in the 1,4-lactone, C 6 H 8 O 4 , is planar and the side chain is in a staggered conformation. The crystal structure of the 1,5-lactone is stabilized by both O-H...O and C-H...O hydrogen bonds and that of the 1,4-lactone by O-H...O hydrogen bonds.