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31.
Two-dimensional mapping by high-performance liquid chromatography of pyridylamino oligosaccharides from various glycosphingolipids. 总被引:1,自引:0,他引:1
A method to map sugars two-dimensionally for the analysis of the structures of oligosaccharides from glycosphingolipids is described. Nine neutral and ten acidic oligosaccharides were obtained from glycosphingolipids by endoglycoceramidase digestion and labelled with 2-aminopyridine. The pyridylamino oligosaccharides were clearly separated by high-performance liquid chromatography on commercially available C18-silica and amide-silica column. All compounds tested were mapped without any overlapping. The separation of the pyridylamino oligosaccharides on the C18-silica column depended on the numbers and positions of sialic acid and N-acetylhexosamine residues; on the amide-silica column, the separation depended on the total number of sugar residues. 相似文献
32.
Production of submicron-size monodisperse polymer particles having aldehyde groups by seeded aldol condensation polymerization 总被引:2,自引:0,他引:2
Submicron-size monodisperse polystyrene/polyglutaraldehyde composite particles having aldehyde groups at the surfaces were produced by seeded aldol condensation polymerization of glutaraldehyde in the presence of polystyrene particles prepared by emulsifier-free emulsion polymerization. This technique is expected to be useful for the production of size-controlled polymer particles having aldehyde groups.Part CXXXVI of the series Studies on Suspension and Emulsion 相似文献
33.
Treatment of l(14S)-β-canadine methochloride (1b) and d(14R)-β-canadine methochloride (1c) with organometals gave d- (2b) and l-2,3-methylenedioxy-9,10-dimethoxyochotensanes (2c), respectively. The structures of these derivatives were proved by chemical and spectral means. The CD spectra of 2b showed Davydov split extrema centered at 284 nm with a positive first Cotton effect, while 2c showed the antipodal curve of 2b. Consequently, the absolute configurations of 2b and 2c were concluded the 14R and 14S, respectively.Application of the anionic rearrangement to N-methyltharictricavine chloride (15) led to 2,3 - methylenedioxy - 9,10 - dimethoxy - 13 - methylochotensane (18) together with the Hofmann methines 16 and 17. The stereochemistry of 18 was confirmed in terms of the nuclear Overhauser effects. 相似文献
34.
Kinetics of chemiluminescence reactions of 2-methyl-6-phenylimidazo[1,2-a]pyrazin-3(7H)-one (1c, Cypridina luciferin analogue) and substituent effects of the 6-aryl group of derivatives 1 strongly suggest that the rate-determining step is a single electron transfer from an anion derived from 1 to a triplet molecular oxygen (O2) in the oxygenation process. 相似文献
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The electronic effect on the regioselectivity in the alkynylation of phenyloxiranes was investigated using three kinds of metal acetylides. BF3 mediated lithium acetylide provided either the α- or β-alkynylated products by controlling the effect of the para-substituents of the phenyloxiranes. LiClO4 mediated lithium acetylide and titanium acetylide, on the other hand, afforded predominantly the β- and α-products, respectively. 相似文献