- Efficient assembly of oligomannosides using the hydrophobically assisted switching phase method
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The hydrophobically assisted switching phase (HASP) method was applied in the assembly of oligomannosides. A new mannosyl donor with high reactivity was selected after a series of optimization studies, which was suitable for the synthesis of oligomannosides via the HASP method. The practicability of the HASP method towards the synthesis of branched oligosaccharides was explored and two branched penta-mannosides were assembled efficiently.
- Meng, Shuai,Tian, Tian,Han, Dong,Wang, Lin-Na,Tang, Shao-Geng,Meng, Xiang-Bao,Li, Zhong-Jun
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supporting information
p. 6711 - 6722
(2015/06/25)
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- A close-packed, highly insulating organic thin monolayer on Si(111)
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A long-chain dialkylated olefin, 2C18 was found to form a close-packed, highly insulating self-assembled monolayer (SAM) on Si(111) via Si-C bond formation. The IR absorption spectra of the 2C18-SAM show that the alkyl chains are densely packed with an all-trans conformation. The threshold voltage to initiate the scanned probe oxidation (SPO) of the 2C18-SAM-covered Si(111) was ca. 9V, which is much higher than the previously reported voltages for organic monolayers on Si or SiO2/Si substrates. Copyright
- Tanaka, Kentaro,Tanaka, Taishi,Hasegawa, Takeshi,Shionoya, Mitsuhiko
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p. 440 - 441
(2008/09/21)
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- Hydrophobically assisted switching phase synthesis: The flexible combination of solid-phase and solution-phase reactions employed for oligosaccharide preparation
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Hydrophobically assisted switching phase (HASP) synthesis is a concept that allows the choice between the advantages of solid-supported chemistry and those of solution-phase synthesis. Starting from the examination of adsorption and desorption properties of hydrophobic molecules to and from reversed-phase silica, we designed a dilipid as a quantitative and fully reversible HASP anchor, permitting final product release. The utility of this new tool in synthetic organic chemistry was demonstrated on oligosaccharide preparation. The synthesis of a pentarhamnoside was accomplished by repetitive glycosylation reactions. Glycosylations were conducted preferably in solution, whereas all protecting group manipulations were performed on solid support. Without the need for chromatographic purification of intermediates, the HASP system furnished the final product after 12 linear steps with average yields of 94% per step at a scale of 0.1 mmol, thus overcoming several of the limitations encountered in the solid-phase synthesis of complex carbohydrates. Copyright
- Bauer, Joerg,Rademann, Joerg
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p. 7296 - 7297
(2007/10/03)
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- Amphipatic polycarboxylic chelates and complexes with paramagnetic metals as MRI contrast agents
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Substituted polycarboxylic ligand molecules and corresponding metal complexes of said ligands, preferably paramagnetic metals complexes for generating responses in the field of magnetic resonance imaging (MRI). The paramagnetic complexes of the polycarboxylic ligands possess advantageous tensioactive properties and are useful as MRI contrast media in formulations for investigating the blood pool.
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Page column 28-29
(2010/11/29)
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- Synthesis of 1,3-di-O-alkyl-2-O-(β-glycosyl)glycerols bearing oligosaccharides as hydrophilic groups
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A novel series of synthetic glycolipids, 1,3-di-O-alkyl-2-O-(β-glycosyl)glycerols, and their efficient synthetic route were proposed.These glyceroglycolipids were synthesized in good overall yields and stereoselectivity in five steps via trichloroacetimidate glycosylation with 1,3-di-O-alkylglycerols.This route was applied to prepare the glycolipids bearing a cello- or malto-oligosaccharide with a definite number of sugar residues from one to six.Thin-layer chromatography, elemental analysis, nuclear magnetic resonance spectroscopy and infrared absorption spectroscopy confirmed that these glycolipids were chemically pure compounds.Keywords: Glyceroglycolipids; Oligosaccharide headgroups; Synthesis
- Minamikawa, Hiroyuki,Murakami, Teiichi,Hato, Masakatsu
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p. 111 - 118
(2007/10/02)
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- 75 Se and 123m Te Compounds for fat resorption tests
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The invention relates to a method of determining the fat resorption, in which a radio-active test fat and reference substance are orally administered. According to the present invention a triether or glycerol of which one or more oxygen atoms are substituted by atoms of the isotope 75 Se or 123m Te, is used as a reference substance. In a preferred embodiment use is made of 125 I- or 131 I-triolein as test fat. The proposed reference substances are novel compounds. A suitable reference substance is for example 1-butylselenyl-75 -Se-2,3-dioctadecyloxypropane.
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