Applications of Tin-Containing Intermediates to Carbohydrate Chemistry

In less than the last two decades a fundamentally new role of carbohydrates in living organisms1 has emerged: conjugates of oligosaccharides with proteins or lipids proved to be the major information carriers between cells and their surroundings.2-4 The need for these specific substances in quantities larger than isolable from biological sources in order to thoroughly understand their biological functions has brought about the renaissance of synthetic carbohydrate chemistry.5-8 A quest for compounds which can mimic the above natural substances by way of similar structure and/or biological action (the so-called mimetics) has also arisen and stimulated elaboration

Carbanionic reactivity of the anomeric center in carbohydrates.

Publisher Summary This chapter presents a review about the chemistry and developments of fluorinated carbohydrates. Because of the high C–F bond energy, glycosyl fluorides are stable in comparison to the other glycosyl halides, and this character has attracted much attention. Deoxyfluoro sugars labeled with fluorine-18 have important applications as imaging agents. Numerous 5-fluorouracil derivatives have been prepared as potential anticancer agents. Fluorine-18 is not known naturally (natural fluorine is all 19 F), but it may be prepared in a variety of artificial nuclear reactions. Several 1-phosphates of deoxyfluoro sugars have been prepared and their acid-catalyzed hydrolysis has been studied. The fluorination of aminoglycosides and anticancer antibiotics has been undertaken to obtain the derivatives of enhanced activity and decreased toxicity. The knowledge concerning the conformation of nucleosides is important in pursuing the relationship between the structure and biological activity of compounds containing fluorinated carbohydrates. Much effort has been devoted to preparing natural nucleoside analogs having effective antiviral (mostly antiherpetic) and antitumor activities with low cytotoxicity for the host cells.

Chemistry and Developments of Fluorinated Carbohydrates

Der Krieg gegen pathogene Bakterien ist noch nicht vorbei! Zwar bilden Vancomycin und andere Glycopeptid-Antibiotika eine letzte Verteidigungslinie gegen zahlreiche mehrfachresistente Bakterien, doch ihr leichtfertiger Gebrauch hat zur Bildung etlicher gefahrlicherer Bakterienstamme gefuhrt Das Verstandnis der chemischen und biologischen Eigenschaften dieser hochkomplexen Glycopeptide durfte eine entscheidende Rolle fur die Entdeckung und Entwicklung neuer Antibiotika spielen

Chemie, Biologie und medizinische Anwendungen der Glycopeptid-Antibiotika

Copper(II) complexes of tridentate dianionic beta-ketoenaminic ligands derived from differently functionalized amino-deoxyglucoses were synthesized and characterized with respect to their structural, spectroscopic, and catalytic properties. The (probably dimeric) complex [1,2-O-isopropylidene-6-N-(3-acetyl-2-oxobut-3-enyl)amino-6-deoxyglucofuranoso)copper(II) Cu(3a) was a highly efficient catalyst for the catechol-oxidase-like oxidation of 3,5-di-tert-butylcatechol (dtbc) into 3,5-ditert-butylquinone (dtbq) by molecular oxygen (kcat=2.63s(-1)). In contrast to this magnetically "normal" complex Cu(3a), the analogous dinuclear complex [[Cu(2a)]2], derived from the isomeric amino sugar 5-amino-5-deoxyglucofuranose, forms six-membered chelate rings with the sugar moiety and has very strong antiferromagnetic-coupled copper atoms (resulting in a diamagnetic ground state). It has a rather insignificant activity (kcat < 10(-3)s(-1)). The ligand H2 1a, derived from a (protected) 6-amino-6-deoxyglucopyranose, forms a trinuclear complex [[Cu(1a)]]2.Cu(OAc)2] in which two basic formula units are bridged by one copper acetate. This compound and the complex derived from an (isomeric) aminodeoxyglucopyranose ([Cu(4a)]: kcat approximately equals 0.03 s(-1)) show moderate activity. All complexes with a peripheral ethoxycarbonyl group instead of the acetyl substituent R2, Cu(1b)-Cu(3b) and Cu(4c), are inactive. The complexes derived from 2-hydroxocyclohexylamine, Cu(5a) and Cu(5c), which were used as models of the active complex Cu(3a), have the typical "cubane-like" tetranuclear structure known from many copper complexes with derivatives of saturated 2-aminoalcohols. They are inactive with respect to the activation of dioxygen.

Copper(II) Complexes of Aminocarbohydrate β-Ketoenaminic Ligands: Efficient Catalysts in Catechol Oxidation

The synthesis of evernitrose and 3-epi-evernitrose

Stereoselectivities in the reaction of methyl 4,6-O-benzylidene-α- and -β-d-hexopyranosid-2-uloses with diazomethane☆

Synthesis of methyl 4-deoxy-3-C-[(S)-1,2-dihydroxyethyl]-α-d-xylo-hexopyranoside and methyl 2,2′-anhydro-3-C-[(S)-1,2-dihydroxyethyl]-α-d-glucopyranoside derivatives

Stereoselectivity in the peroxy acid oxidation of methyl 4,6-O-benzylidene-3-O-methyl-2-C-methylene-α-D-ribo-hexopyranoside (1b), its 3-epimer (2b), β-anomer of 1b and 2b, methyl 4,6-O-benzylidene-2-O-methyl-3-C-methylene-α-D-arabino-hexopyranoside and its 2-epimer was examined The results were compared with those of rigid methylenecyclohexane systems

Branched-chain Sugars. XVII. Stereoselectivity in the Oxidation of Several Methyl 4,6-O-Benzylidene-2-C- or -3-C-methylene-α- and-β-D-hexopyranosides with m-Chloroperbenzoic Acid

Ken-ichi Sato

Papers

The synthesis of evernitrose and 3-epi-evernitrose

Stereoselectivities in the reaction of methyl 4,6-O-benzylidene-α- and -β-d-hexopyranosid-2-uloses with diazomethane☆

Synthesis of methyl 4-deoxy-3-C-[(S)-1,2-dihydroxyethyl]-α-d-xylo-hexopyranoside and methyl 2,2′-anhydro-3-C-[(S)-1,2-dihydroxyethyl]-α-d-glucopyranoside derivatives

Branched-chain Sugars. XVII. Stereoselectivity in the Oxidation of Several Methyl 4,6-O-Benzylidene-2-C- or -3-C-methylene-α- and-β-D-hexopyranosides with m-Chloroperbenzoic Acid

Complementary stereoselectivity in the reactions of hexopyranosid-4-uloses with methylmagnesium iodide and methyllithium