A new and direct access to glycono-1,4-lactones from glycopyranoses by regioselective oxidation and subsequent ring restriction
TL;DR: In this article, the authors show that the treatment of partially protected or unprotected carbohydrates with the RhH(PPh 3 ) 4 -benzalacetone system leads exclusively to glycono-1,4-lactones by regioselective oxidation and subsequent ring restriction.
About: This article is published in Tetrahedron Letters.The article was published on 1995-01-16. It has received 39 citations till now. The article focuses on the topics: Ring (chemistry) & Regioselectivity.
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TL;DR: In this article, the advantages of using water as a solvent are discussed and related to the hydrophobic effects and the hydrogen-bonding ability of water with a special emphasis on its very high cohesive energy density which strongly favors organic reactions having a negative activation volume.
Abstract: Organic reactions using water as solvent are reviewed with a focus on pericyclic reactions, carbonyl additions, stoichiometric organometallic reactions, oxidations and reductions which show an unusual outcome in terms of reactivity and selectivity compared with those performed in organic solvent. The advantages of using water as a solvent are discussed and related to the hydrophobic effects and the hydrogen-bonding ability of water with a special emphasis on its very high cohesive energy density which strongly favors organic reactions having a negative activation volume.
103 citations
TL;DR: Sulfonimines derived from aryl and nonenolizable aliphatic aldehydes can be effectively allylated to the corresponding homoallylic sulfonamides with allylic bromides promoted by indium or zinc.
98 citations
TL;DR: Amine-linked pseudodisaccharides are obtained when primary carbohydrate alcohols are used as the coupling partners and in the presence of Cs(2)CO(3), which allows regioselective reactions.
78 citations
TL;DR: This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates into glycoconjugates through the anomeric position.
Abstract: Glycobiology is the comprehensive biological investigation of carbohydrates. The study of the role and function of complex carbohydrates often requires the attachment of carbohydrates to surfaces, their tagging with fluorophores, or their conversion into natural or non-natural glycoconjugates, such as glycopeptides or glycolipids. Glycobiology and its "omics", glycomics, require easy and robust chemical methods for the construction of these glycoconjugates. This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates into glycoconjugates through the anomeric position. The discussion is divided in terms of the anomeric bond type of the newly formed glycoconjugates, including O-, N-, S-, and C-glycosides.
68 citations
TL;DR: Tin-mediated additions of allylic bromides to aldehydes and aldoses leads to adducts with high diastereo- and diastereofacial selectivity in the presence of indium trichloride in water as mentioned in this paper.
Abstract: Tin-mediated additions of allylic bromides to aldehydes and aldoses leads to adduct with high diastereo- and diastereofacial selectivity in the presence of indium trichloride in water.
65 citations
References
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TL;DR: In this paper, a single-stage synthesis for a range of important hydride-, carbonyl-, and nitrosyl-containing triphenylphosphine complexes of the platinum metals is described.
Abstract: Convenient, single-stage syntheses have been devised for a range of important hydride-, carbonyl-, and nitrosyl- containing triphenylphosphine complexes of the platinum metals. The reactions are performed in homogeneous, alcoholic solutions from which the required products precipitate or crystallise cleanly; sodium borohydride, aqueous formaldehyde, and N-methyl-N-nitrosotoluene-p-sulphonamide are used as convenient sources of hydride, carbonyl, and nitrosyl ligands respectively. Abstraction of hydrogen chloride to form co-ordinatively unsaturated derivatives is achieved by introduction of triethylamine to the reaction solution. New compounds prepared and characterised include [OsH4(PPh3)3] and [Ru(NO)2(PPh3)2]. The latter compound is the first well characterised dinitrosyl of ruthenium.
154 citations
TL;DR: Methyl sulfoxide-acetic anhydride was shown to be an effective reagent for the oxidation of an isolated secondary alcohol group in a carbohydrate derivative to the corresponding ketone; the reagents are removed by lyophilization to give the product in high yield.
92 citations
60 citations
48 citations
Journal Article•
TL;DR: Results support a role for beta-NAG in degradation of extracellular matrix components and suggest the usefulness of hexosaminidase inhibitors as potential anti-invasive agents.
Abstract: Human ovarian carcinoma (HOC) cell beta-N-acetylglucosaminidase (beta-NAG, EC 32130) was found to be present in three isoenzymatic forms All three forms were capable of degrading ECM Therefore, inhibitors of beta-NAG were sought as potential anti-invasive agents Two sugar analogs, 2-acetamido-2-deoxy-1,5-gluconolactone (CD80110) and 2-acetamido-1,5-imino-1,2,5-trideoxy-D-glucitol (CD 86022), were evaluated for their ability to inhibit 1) human ovarian carcinoma beta-NAG isoenzyme activities, 2) degradation of radiolabeled ECM mediated by HOC cells and beta-NAG, and 3) cell growth Both compounds were found to be competitive inhibitors of beta-NAG isoenzyme activities, with Ki values similar for all isoenzymes (2-8 microM) CD 80110 and CD 86022 inhibited HOC cell-mediated degradation of [3H]glucosamine labeled ECM without notable effect on cell growth Enzyme-mediated degradation of ECM was also inhibited by both sugar analogs Analysis of degradation products after cell- or enzyme-mediated digestion of ECM revealed a decrease in the amount of both free aminosugars and high molecular material caused by inhibitors These results support a role for beta-NAG in degradation of extracellular matrix components and suggest the usefulness of hexosaminidase inhibitors as potential antiinvasive agents
48 citations