摘要:

A synthetic process is outlined in which an allylic alcohol is converted into its primary urethane derivative, which is then subjected to iodonium ion induced cyclization to give a single iodo-carbonate. The carbonate is then deiodinated reductively and hydrolyzed to afford the vicinal diol. By use of this process the two title sugars have been prepared from methyl 2.3.6-trideoxv-α-L-ervthro-hex-2-enopvranoside and its α-L-threo counterpart.

ISSN:0732-8303    

DOI:10.1080/07328308508062945

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The reaction of equimolar amounts of D-xylose and glycine in D2O at 68°C resulted in the formation of a twelve carbon compound, as a major product. No intermediate was detected in the formation of this dimer. The eneaminol, formed on reaction of 0.1 molar D-xylose and glycine in H2O, after six weeks was isolated and purified. Based on1H and13C NMR, spin echo Fourier transform experiments, and other spectroscopic techniques including FAB-MS and CI-MS of TMS derivative, the structure: N, N[1-deoxy-D-threo-pent-2-enitol, 1′-deoxy-β-D-threo-pentose (2′,5′)] glycine, was assigned to the product.

ISSN:0732-8303    

DOI:10.1080/07328308508062946

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The stereochemistry of the reaction of the conjugate base of nitromethane with aldehydosugars was shown to depend on the reaction conditions and the structure of the glycosyl group. Some reactions of a novel type of synthetic intermediates in carbohydrate chemistry, thegem-bromonitroenoses are described.

ISSN:0732-8303    

DOI:10.1080/07328308508062947

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A procedure is described for a simple preparation that produces mixtures of a majority of the possibleO-methylated alditol acetate derivatives of neutral monosaccharides. The derivatives can be used as standards to determine both the linkage positions and the precise identities of sugar constituents in cell wall poly-saccharides.

ISSN:0732-8303    

DOI:10.1080/07328308508062948

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The equilibrium of 1,3-dihydroxy-2-propanone (dihydroxyacetone) and 2,3-dihydroxypropanal (glyceraldehyde) and their dehydration reaction to methylglyoxal has been studied in the range of 180 - 240 °C under hydrothermal reaction conditions. A reaction mechanism for the conversion of these C-3 compounds was formulated which allowed the calculation of the product yields. In the investigated temperature range both compounds produce a maximum of 30-40% of methylglyoxal.

ISSN:0732-8303    

DOI:10.1080/07328308508062949

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Flash chromatography of the mixture obtained by reaction of L-rhamnose with methanol in the presence of cation-exchange resin, in addition to methyl α-L-rhamnofuranoside (3) and methyl rhamnopyranosides1and2gave methyl β-L-rhamnofuranoside (4) in 8% yield.13C and1H NMR spectra of3and4as well as their calculated conformation in solution are discussed.

ISSN:0732-8303    

DOI:10.1080/07328308508062950

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Carbon-13 NMR data are provided for a series ofN-glycosyl amines and Amadori rearrangement products that were prepared by reaction of D-glucose with substituted anilines. These data demonstrate that13C NMR is a useful method for characterizing the products isolated from reactions of D-glucose with amines.

ISSN:0732-8303    

DOI:10.1080/07328308508062951

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A higher carbon carbohydrate moiety of antibiotic tunica-mycins named tunicamine has been synthesized in a protected form. The key reaction step of the synthesis is a potassium fluoride catalyzed Henry reaction of a 5-nitroribose derivative and a dial do-galactosamine derivative. The tunicamine derivative has been converted to a tunicaminyl uracil derivative by condenation with bis(trimethylsilyl) uracil.

ISSN:0732-8303    

DOI:10.1080/07328308508062952

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

3-Amino-2-fluoro-2,3,6-trideoxy-L-galactose 10 (α-fluoro-L daunosamine) was synthesized in ten steps starting from methyl-2, 3-anhydro-4,6-0-benzylidene-α-D-mannopyranoside (overall yield 70%). Et3N, 3HF complex was used as the fluorinating agent, according to our previous work, for replacement of a mesyl groun. Neighbouring-group participation lead to a fluorinated product with retention of configuration. The structure of10was determined by1H and19F NMR spectroscopy.

ISSN:0732-8303    

DOI:10.1080/07328308508062953

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Recent syntheses of alkyl glycosides have involved a rnodification of the Koenigs-Knorr reaction in which a sugar peracetate is first brominated and finally reacted with the desired alcohol in the presence of silver ion as a catalyst. In 1980 Rosevear et a1.2reported a simplified synthesis of alkyl glycosides in which the acetobromosugar was not isolated, but was reacted with the alcohol and the deacetylated final product was purified using column chromatography on Dowex 1. While yield s obtained for alkyl glucosides by this procedure were as high as 60%, those for alkyl maltosides were only 25%. More recently Landauer et a1.3 have reported yields of 55 to 68% in the preparation of alkyl malto-sides. However, their procedure involves t h e isolation and purification of the acetobromosugar intermediate and reported yields are calculated on the basis of this intermediate.

ISSN:0732-8303    

DOI:10.1080/07328308508062954

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor