A simple and rapid method for the permethylation of carbohydrates

Glycoproteins, glycolipids, and glycophospholipids (glycoconjugates) are components of membranes. The oligosaccharide residue is responsible for intercellular recognition and interaction; it acts as a receptor for proteins, hormones, and viruses and governs immune reactions. These significant activities have stimulated interest in oligosaccharides and glycoconjugates. With their help it should be possible to clarify the molecular basis of these phenomena and to derive new principles of physiological activity. Major advances in the synthesis of oligosaccharides have been made by the use of the Koenigs-Knorr method, in which glycosyl halides in the presence of heavy-metal salts are employed to transfer the glycosyl group to nucleophiles. The disadvantages of this procedure have led to an intensive search for new methods. Such methods will be discussed in this article. Emphasis is placed on glycoside and saccharide formation by 1-O-alkylation, on the trichloroacetimidate method, and on activation through the formation of glycosylsulfonium salts and glycosyl fluorides.

New Methods for the Synthesis of Glycosides and Oligosaccharides—Are There Alternatives to the Koenigs‐Knorr Method? [New Synthetic Methods (56)]

https://www.jbc.org/content/243/3/616.full.pdf

Structures and Immunochemical Properties of Oligosaccharides Isolated from Pig Submaxillary Mucins

Determination of aminosugar linkages in glycolipids by methylation: Aminosugar linkages of ceramide pentasaccharides of rabbit erythrocytes and of Forssman antigen☆

The distribution of actin in wild-type cells and in morphogenetic mutants of the budding yeast Saccharomyces cerevisiae was explored by staining cells with fluorochrome-labeled phallotoxins after fixing and permeabilizing the cells by several methods. The actin appeared to be localized in a set of cortical spots or patches, as well as in a network of cytoplasmic fibers. Bundles of filaments that may possibly correspond to the fibers visualized by fluorescence were observed with the electron microscope. The putative actin spots were concentrated in small and medium-sized buds and at what were apparently the sites of incipient bud formation on unbudded cells, whereas the putative actin fibers were generally oriented along the long axes of the mother-bud pairs. In several morphogenetic mutants that form multiple, abnormally elongated buds, the actin patches were conspicuously clustered at the tips of most buds, and actin fibers were clearly oriented along the long axes of the buds. There was a strong correlation between the occurrence of active growth at particular bud tips and clustering of actin spots at those same tips. Near the end of the cell cycle in wild-type cells, actin appeared to concentrate (as a cluster of spots or a band) in the neck region connecting the mother cell to its bud. Observations made using indirect immunofluorescence with a monoclonal anti-yeast-tubulin antibody on the morphogenetic mutant cdc4 (which forms multiple, abnormally elongated buds while the nuclear cycle is arrested) revealed the surprising occurrence of multiple bundles of cytoplasmic microtubules emanating from the one duplicated spindle-pole body per cell. It seems that most or all of the buds contain one or more of these bundles of microtubules, which often can be seen to extend to the very tips of the buds. These observations are consistent with the hypotheses that actin, tubulin, or both may be involved in the polarization of growth and localization of cell-wall deposition that occurs during the yeast cell cycle.

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Relationship of actin and tubulin distribution to bud growth in wild-type and morphogenetic-mutant Saccharomyces cerevisiae.

Zur Permethylierung von Zuckern und Glykosiden

Triphenylformazan last sich mit Dimethylsulfat bzw. Methyljodid, aber auch mit Formaldehyd bzw. Methylenjodid, in ein tief grunes freies Radikal verwandeln. Mit weiteren Alkylhalogeniden bzw. Aldehyden sowie mit anderen Formazanen sind eine ganze Reihe von Radikalen dieses Typs (Verdazyle) dargestellt worden. Ihre chemischen und physikalischen Eigenschaften werden beschrieben. Im Zusammenhang mit den ESR-Spektren wird die Frage der Formulierung erortert. Mit Halogenen entsteht aus dem grunen Radikal 1,3,5-Triphenyl-verdazyl (V) das entsprechende violette Kation, das diamagnetisch ist. Durch Reduktionsmittel werden die Verdazyle unter Aufnahme von 1 H-Atom in farblose Verbindungen verwandelt, aus denen die tieffarbigen Radikale, meist schon durch Luftsauerstoff, zuruckgebildet werden. Die Ruckverwandlung in Formazane gelang auf photochemischem Wege. Beim thermischen Abbauwurden unter Ringverengung Triazole erhalten.

Über Verdazyle, eine neue Klasse cyclischer N-haltiger Radikale

Bei Methylierungen in Dimethylformamid ist es vielfach von Vorteil, Dimethylsulfat an stelle von Methyljodid zu verwenden. Substanzen, die in Dimethylformamid zu wenig loslich sind, methyliert man in Dimethylsulfoxyd bzw. in Dimethylformamid/Dimethylsulfoxyd-Gemischen. Auf diese Art wurde Mesoinosit-hexamethylather kristallisiert (Schmp. 18°) erhalten.

Permethylierung von Inosit und anderen Kohlenhydraten mit Dimethylsulfat

Preparation of tetramethylrhodaminyl-phalloidin and uptake of the toxin into short-term cultured hepatocytes by endocytosis

Das Tetrasaccharid Lycotetraose, das im Tomatin mit Tomatidin verknupft ist, lies sich strukturell aufklaren, indem 1. Tomatin, 2. das daraus durch Abspaltung von D-Xylose gewonnene Glykosid (β1-Tomatin) und 3. das xylosefreie Trisaccharid (Lycotriose), letzteres nach katalytischer Hydrierung zum Lycotriit, mit Methyljodid und Silberoxyd in Dimethylformamid permethyliert wurden. Aus den Spaltstucken der permethylierten Verbindungen, die kristallisiert erhalten wurden, ergibt sich fur die Lycotetraose die verzweigte Konstitution einer β-D-Glucopyranosyl(1 2Glucose)-β-D-xylopyranosyl(1 3Glucose)-β-D-glucopyranosyl(1 4Galaktose)-α-D-galaktopyranose und damit fur das Tomatin die Formel I. Auch aus Demissin last sich, unter Abspaltung von D-Xylose und des Aglykons, kristallisierte Lycotriose gewinnen.

Heinrich Trischmann

Papers

Zur Permethylierung von Zuckern und Glykosiden

Über Verdazyle, eine neue Klasse cyclischer N-haltiger Radikale

Permethylierung von Inosit und anderen Kohlenhydraten mit Dimethylsulfat

Preparation of tetramethylrhodaminyl-phalloidin and uptake of the toxin into short-term cultured hepatocytes by endocytosis

Die Konstitution der Lycotetraose