摘要:

Attention has been recently directed toward synthesis of various types of heterocyclic derivatives, among them nucleoside analogs with potential antibacterial and antitumor properties.1Although a number of synthetic approaches have been developed, there are a few methods that appear to have the versatility for construction of a variety of heterocyclic systems. Among these are approaches that employ heterocyclic elaboration of glycosyl cyanides,2important-glycosyl intermediates that have been used in the synthesis of a number of naturally occurring-nucleoside antibiotics3as well as many analogs.2,4

ISSN:0732-8303    

DOI:10.1080/07328308408057903

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Polysulfated oligosaccharides obtained from enzymatic digests of chondroitin sulfate have been successfully analyzed by positive and negative ion fast atom bombardment mass spectrometry. The spectra show intense cationized molecular ions and fragment ions from which sugar sequence and sites of sulfation can be readily determined. In addition, polymers of 4-O-sulfate and 6-O-sulfate positional isomers may be distinguished by fast atom bombardment mass spectrometry. The mass spectra also indicate the presence of structural homologs of chondroitin sulfate that contain more than one covalently bound sulfate moiety per two sugar residues. The effects of salt concentration, liquid matrix composition and ionization mode (negative versus positive ion abstraction) on the quality and information content of the mass spectra are discussed in detail.

ISSN:0732-8303    

DOI:10.1080/07328308408057904

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Prolonged treatment of tetra-O-acetyl-1, 5-anhydro-hex-1-enitols (“tetra-O-acetyl-hydroxy-glycals”)3and5with BF3in CH2Cl2at RT lead to anomeric mixtures of the title compounds2and4a, the α-anomer4adominating. Reaction of5gave the higher yields of4a(71%) and2(12%), the results being accounted mechanistic grounds. The same reaction performed in an aromatic solvent, like toluene, gave rise to competingC-alkylation., Theorthoandpara-tolyl derivatives6and7, also with enone structure, were isolated in a combined maximum yield of 40% from5. β-Enone2was also prepared in moderate yield by thermolysis of β-d-glucopyranose pentaacetate (1). In this case no α-anomer4awas detected.

ISSN:0732-8303    

DOI:10.1080/07328308408057905

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

2-Chloroethylnitrosourea derivatives of sucrose have been synthesized as potential antineoplastic agents. Two compounds: 6-[[[(2-chloroethyl)nitrosoamino]carbonyl]amino]-6-deoxysucrose and 6′-[[[(2-chloroethyl)nitrosoamino]carbonyl]amino]-6′-deoxysucrose exhibited significant antitumor activity against experimental leukemia L1210 in mice. Their chemical decomposition rates (T0.5) have been determined.

ISSN:0732-8303    

DOI:10.1080/07328308408057906

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The Henry reaction of (2S)-2-benzyloxypropanal with (2S)-1,2-O-isopropylidene-4-nitro-1,2-butanediol, leading to naturally occurring 3-amino-2,3,6-trideoxy-L-hexoses, acosamine and ristosamine, is described.

ISSN:0732-8303    

DOI:10.1080/07328308408057907

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A facile and regiospecific dehydration of 2-deoxy 2-C-methyl sugars using the triphenylphosphine-diethylazodicarboxylate reagent is reported. This reaction allowed us to prepare the title compound which is a crucial intermediate in the total synthesis of natural products. Its absolute configuration is firmly established by X Ray analysis.

ISSN:0732-8303    

DOI:10.1080/07328308408057908

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Methyl 2-acetamido-2, 3-dideoxy-α-d-glucopyranosides have ceen obtained by an elimination reaction of the corresponding 3-O-mesylallopyranoside with NaH or DBU follcwed by hydrogenation over Pd/C. Reaction of 2-acetaido-2-deoxy-3-O-mesylallopyranosides with inorganic azides under phase transfer reaction conditions afforded 2-acetamido-3-azido-2, 3-dideoxy-gluccyranoses which after hydrogenation over Pd/C gave 2-acetamido-3-amino-2,3-dideoxy-D-glucopyranoses.

ISSN:0732-8303    

DOI:10.1080/07328308408057909

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The Wittig reaction of methyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-d-ribo-hexopyranosid-3-ulose witethoxycarbonylmethylenetriphenylphosphorane afforded the corresponding 3-C-(E)-ethoxycarbonyle-thyiene-3-deoxy glycoside3. Catalytic hydrogenation of3(Pd/C) gave stereoselectively, after removal of benzylidene and ethyl ester protecting groups, methyl 2-acetamido-3-C-carboxymethyl-2,3-dideoxy-α-D-allo-hexopyranoside (11).

ISSN:0732-8303    

DOI:10.1080/07328308408057910

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Antibiotic A231871is a cation ionophore highly specific for Ca2+. Because of its unique dioxaspiro ring structure as well as its biological activities,2several synthetic approaches to the compound have been reported.3We report here the first example of the total synthesis ofbased on the use of a carbohydrate template.4The target structurewas synthesized from the chiral synthons or “chirons”5andvia a key intermediate, as shown in Scheme I. A thermodynamically controlled, acid catalyzed ring closure ofwas expected to provide a correct configuration at the spiro center C-14 according to the anomeric effect.6The two chironsandwere prepared from-glucose via the same intermediate-as follows (Scheme II).

ISSN:0732-8303    

DOI:10.1080/07328308408057911

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0732-8303    

DOI:10.1080/07328308408057902

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor