摘要:

1-O-Methyl analogs of mucin oligosaccharide components, D-GalNAc (1aand1b). β-D-Galp-(1-3)-D-GalNAc (2) and β-D-Galp(1-3)-[β-D-GlcNAc-(1-6)]-D-GalNAc (3) in which the H-6proSproton was selectively replaced by a deuterium, were synthesized to study the solution conformations about the C5-C6 fragments by1H-NMR spectroscopy. The study revealed the preference of thegt-conformer for these sugars.

ISSN:0732-8303    

DOI:10.1080/07328308808058940

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Methyl 2,6-dideoxy-4-O-methyl-α-D-arabino-hexopyranoside13and its L-enantiomer14were synthesized in a 5-step sequence starting from either 6-deoxy-D-glucal or L-rhamnal. The D-enantio-mer was proven to be identical with the non-reducing sugar of the tetrasaccharide moiety of the major phenol glycolipid, a cell wall antigen ofMycobacterium kansasii.

ISSN:0732-8303    

DOI:10.1080/07328308808058941

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The first completed chemical synthesis of Agrocinopine A (5) is presented. The key step in the synthesis was the pivaloyl chloride promoted condensation of a blocked arabinose 2-H-phosphonate derivative 3 with a protected sucrose derivative 1 having a free hydroxyl at 4′-OH. The resulting H-phosphonic acid diester was oxidisedin situwith iodine to produce the corresponding phosphodiester 4, which was subsequently deblocked to give Agrocinopine A.

ISSN:0732-8303    

DOI:10.1080/07328308808058942

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The 5-0-benzoyl derivatives3and4derived from 1,6-anhydro-β-D-mannpfuranose and -α-L-gulofuranose are suitable educts for the preparation of the isomeric olefins7and8by Corey-Winter elimination via the thionocarbonates5and6, respectively.8was prepared in higher yields also from 5-α-Benzoyl-1,6-anhydro-α-L-talofuranose (14) via15. Payne oxidation of the unsaturated compounds7and8gave theexoepoxides9and10with D-alloand L-taloconfiguration.

ISSN:0732-8303    

DOI:10.1080/07328308808058943

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Potassium-graphite laminate (C8K) in oxolane almost instantaneously convertsO-alkyl andO-aUcylidene pyranosyl and furanosyl chlorides under extremely mild conditions and in high yields into pyranoid and furanoid glycals, which in the presence of an additional mole of C8K, are efficientlyO-alkylated orO-silylated In easily conducted one-pot reactions.

ISSN:0732-8303    

DOI:10.1080/07328308808058944

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

D-Ribose, D-arabinose and D-glucose react with nitriles in liquid hydrogen fluoride to give the corresponding 1,2-cisconfigurated N-acyl-pento (or hexo) furanosyl amines 1-7 and9. D-Xylose gives the ct-pyranosyl isomer8beside the α-furanosyl main product7. D-Mannose and L-rhamnose yield the N-acyl-α-hexopyranosyl amines 10 and 11.

ISSN:0732-8303    

DOI:10.1080/07328308808058945

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Synthesis of methyl 2,6-dideoxy-4-O-methyl-α-D-arabino-hexopyranoside (2) has been accomplished starting from readily available methyl 2-deoxy-α-D-arabino-hexopyranoside (3). The derived 4,6-dimesylate derivative7was simultaneously deoxygenated and hydrolysed at C-6 and C-4 with lithium aiuminatm hydride in refluxing tetrahydrofuran. subsequent methyíaíion and debenzyǐation of 8 gave the title product.

ISSN:0732-8303    

DOI:10.1080/07328308808058946

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Recently we have reported the addition of trichloracetyl isocuyanate to glycals11,2,3. The reaction led to the highly stereoselective formation of a mixture of unstable [2+2] and [4+2] cycloadducts2and3. The isocyanate adds to the glycal moietyantito the substituent at C-3. The addition of benzylamine to the reac6tion mixture led to N-deprotection of2and allowed us to isolate stable bicyclic β-lactams41-3. We have shown also that2(a mixture of α-L-gluco and β-L-manno isomers) obtained from L-rhamnal1(R1˭Ac, R2˭CH3under high pressure, when treated with methanol, underwent a rapid trans opening of the four-membered ring to give respective glycosides5(β-L-gluco and α-L-mannoisomers). On the other hand3(R1˭Ac, R2˭CH3) under the same conditions added a molecule of methanol to the C˭N double bond affording 6.

ISSN:0732-8303    

DOI:10.1080/07328308808058947

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

LTB411, a member of the arachidonic acid cascade has been identified by Borgeat and Samuelsson1. LTB4is a potent chemotactic factor and it is now considered as the chemical mediator implicated in inflammatory processes.

ISSN:0732-8303    

DOI:10.1080/07328308808058948

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0732-8303    

DOI:10.1080/07328308808058949

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor