Acyclic Sugar Research Articles

Synthesis of acyclic sugar aldehydes by ozonolysis of oximes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of acyclic sugar aldehydes by ozonolysis of oximesDavid J. Weitz and Mark D. BednarskiCite this: J. Org. Chem. 1989, 54, 20, 4957–4959Publication Date (Print):September 1, 1989Publication History Published online1 May 2002Published inissue 1 September 1989https://doi.org/10.1021/jo00281a046RIGHTS & PERMISSIONSArticle Views459Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (492 KB) Get e-Alerts Get e-Alerts

Conformations of acyclic sugar derivatives. 8. Partially acetylated alditols

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformations of acyclic sugar derivatives. 8. Partially acetylated alditolsStephen J. Angyal and Ronan Le FurCite this: J. Org. Chem. 1989, 54, 8, 1927–1931Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989https://doi.org/10.1021/jo00269a033RIGHTS & PERMISSIONSArticle Views64Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (647 KB) Get e-Alerts Get e-Alerts

Efficient synthesis of 1,2- seco and 1,2- seco 2- nor pyrimidine and purine nucleosides

Unprotected silylated purines and pyrimidines (adenine, guanine, cytosine, thymine) reacted with acetoxymethyl ether (acyclic sugar analogues) under solid PTC conditions, using KI and dibenzo-18-crown-6 in benzene-acetonitrile (1:1, v/v) to give regiospecifically the corresponding N-9 purine and N-1 pyrimidine acyclic nucleosides in fairly good yields.

ChemInform Abstract: Synthesis of Carbohydrate Epoxides Under Phase‐Transfer Conditions.

AbstractThe acyclic sugar diols (I) and (III) are treated with tosyl chloride under phase‐transfer conditions to give the corresponding epoxides (II) and (IV) respectively.

Ribose-modified adenosine analogues as adenosine receptor agonists.

Analogues of the potent adenosine receptor agonist (R)-N-(1-methyl-2-phenylethyl)adenosine (R-PIA), modified at N9, were prepared and evaluated for adenosine A1 and A2 receptor binding and in vivo central nervous system and cardiovascular effects. The modifications at N9 include deoxy sugars, 5'-substituted-5'-deoxyriboses, non-ribose sugars, sugar ring homologues, and acyclic sugar analogues. Most of the derivatives have poor affinity for adenosine receptors. Only minor modifications at C5' and C3' maintain potent binding. In general, those derivatives exhibiting in vivo behavioral or cardiovascular effects also have the highest affinity for adenosine receptors.

Un nouvel exemple de nucléoside à sucre ramifié insaturé: la désoxy‐3′‐méthylidène‐3′‐adénosine

A Novel Example of Unsaturated Branched‐chain Sugar Nucleoside: 3′‐Deoxy‐3′‐methylidene‐adenosineStarting from 5‐O‐benzoyl‐3‐C‐methylidene‐3‐deoxy‐1,2‐O‐isopropylidene‐α‐D‐erythro‐pentofuranose (11) the title compound 8 has been prepared. Its α‐anomer (9) and the acyclic sugar nucleoside 10 have been obtained as by‐products. Adenosine deaminase slowly deaminated 8, 9 being not affected. Compound 8 exhibited no antiviral activity, whereas one of its saturated analogues (13) inhibited the multiplication of the herpes‐1 (HF) virus.

Synthesis of asymmetrically-substituted cyclopentane derivatives from acyclic sugars

Diels–Alder addition of cyclopentadiene and trans-α,β-unsaturated sugar derivatives proceeds with high steric control to afford crystalline, optically pure norbornene derivatives that may be transformed into tetra-C-substituted cyclopentane derivatives of defined stereochemistry at all four centres; the products are of interest in synthesis of prostaglandin analogues.

BORON, LIGNIFICATION AND THE ORIGIN OF VASCULAR PLANTS‐A UNIFIED HYPOTHESIS

SUMMARYIt is proposed that the development of an essential role for boron was a prerequisite for the evolution of vascular from prevascular plants since there is a prima jade case that a primary role of boron concerns the biosynthesis of lignin and, in conjunction with auxin, differentiation of xylem. In particular, a potential role for borate in regulating the hydroxylase and oxidase activities of the phenolases involved in the biosynthesis of caffeic and hydroxyferulic acids is suggested. The origin of this role for boron depended on the selection of sucrose in the Chlorophyta as a mobile and storage carbohydrate since, compared with the acyclic sugar alcohols accumulated in other algal groups, sucrose forms only a very weak complex with borate. It is argued that only when borate was not sequestered by complexing with other carbohydrates did the way become clear for it to acquire an essential role. This acquisition catalysed the evolutionary dichotomy between non‐lignified and lignified photosynthetic land‐plants, the bryophytes and tracheophytes. Boron subsequently became involved in two other requirements for success on land ‐ the exploitation of soil for anchorage, water and minerals, and the emancipation of fertilization from external water‐since this element is required for development of adventitious roots (again in conjunction with plant hormones) and, in angiosperms, for germination of pollen.

Carbon-13 nuclear magnetic resonance spectra of acyclic carbohydrate derivatives : alditols, 1,2-bis(phenylhydrazones), and dithioacetals

The carbon-13 n.m.r. spectra of acyclic carbohydrate derivatives, namely alditols. 1,2-bis(phenylhydrazones), dithioacetals, and related acyclic sugar derivatives, are reported. The study has corroborated earlier results, based on 1H n.m.r. investigations, on the conformational behaviour of such compounds in solution. Application of this technique in elucidation of regiospecificity of oxidation of alditols by Acetobacter suboxydans is discussed.

Acyclic sugars: the ring-opening of 2-acetamido-2-deoxyhexopyranoses in trifluoroacetic acid

During an investigation of solvent effects on the anomeric equilibria of 2-acetomido-2-deoxyhexoses, we have observed a novel, reversible reaction of these sugars with trifluoroacetic acid that is described herein. Fig. 1 shows the H-n.m.r. spectra of 2-acetoamido-2 deoxy-D-glucopyranose (1) in trifluoroacetic acid, recorded at intervals after dissolution. A sharp doublet (J = 5.5 Hz) at delta = 7 and a singlet at delta = 2.6 begin to appear within a few min. The increase in the intensity of these resonances is accompanied by a concomitant decrease of the H-1 peak at delta = 5.4 and the methyl resonance at delta 2.4 of 1. The reaction is essentially complete after 3 h, and Fig. 1c shows the spectrum after 19 h. During this conversion, the specific rotation changes from initial alpha D of +49 deg. to a final value of –54.4 deg. Evaporation of the trifluoroacetic acid in vacuo yielded an unstable oil that showed the presence of acetamido and trifluoroacetyl groups (Vco 1680 1795 cm-1). Addition of D2O led to rapid reversal of the reaction. Fig. 2 shows the n.m.r spectra of the oil in D2O, recorded at intervals. The doublet at delta 7 and the singlet at delta 2.6 disappear, whereas the resonances of 1 reappear. An interesting feature of the reverse reaction is the growth and decay of doublet at delta = 6.5 and a methyl resonance at delta 2.15, characteristic of a short-lived intermediate. Analysis of curves of the progress of reaction suggests that consecutive first-order processes are operative.

ChemInform Abstract: SYNTHESIS OF ACYCLIC SUGAR OXAZOLES

The reaction of protected aldonic acid lactones with ethyl isocyanoacetate and base in aprotic medium gives either α(formylamino)acrylic ester derivatives or acyclic sugar oxazole derivatives, where base-catalysed elimination reactions can be suppressed.

Synthesis of acyclic sugar oxazoles

The reaction of protected aldonic acid lactones with ethyl isocyanoacetate and base in aprotic medium gives either α(formylamino)acrylic ester derivatives or acyclic sugar oxazole derivatives, where base-catalysed elimination reactions can be suppressed.

Synthesis and evaluation of acyclic sugar nucleosides.

Acylated aldose dialkyl dithioacetals with bromine undergo replacement of one alkylthio group by bromine. These unstable bromides react, as by fusion with 2,4-bis(trimethylsilyloxy)pyrimidine, to give acylated 1-(pyrimidin-1-yl) derivatives that upon saponification afford acyclic sugar nucleoside analogues, some as separable mixtures of 1-epimers. Systemic stereochemical variants have been conducted. Pmr conformational studies show that the sugar chain is extended in certain examples, whereas others favor folded ("sickle") conformations, in line with a general rationale developed for acyclic-sugar derivatives. Condensation of the bromides with purines gives 9-substituted acyclic-sugar nucleoside analogues; synthesized systematically for various series, these include the D-pentoses in combination with 6-mercaptopurine. In vitro and in vivo biological activities vary according to stereochemistry of the sugar. The position of substitution of the sugar chain, the chirality at C-1', and the tautomeric form of the heterocycle, were established by x-ray crystallography of the product from D-arabinose and 6-mercaptopurine. The x-ray data permit correlation of C-1 chirality throughout the series and pmr data indicate the favored conformations.

Thio sugars: stereochemical questions and synthesis of antimetabolites

Abstract

Synthesis and stereochemical correlation of acyclic sugar nucleoside analogues: X-ray crystal structure of (1R)-2,3,4,5-tetra-O-acetyl-1-S-ethyl-1-(1,6-dihydro-6-thioxopurin-9-yl)-1-thio-D-arabinitol

A crystal structure determination has been used to establish the absolute stereochemistry of a mixed acetal derivative, a nucleoside analogue (1) having purine-6-thione (‘6-mercaptopurine’) attached to an acyclic D-arabinose derivative.

Conformations of acyclic sugar derivatives : Part II. Determination of the conformations of alditol acetates in solution by the use of 250-MHz n.m.r. spectra

The p.m.r. spectra of all the fully acetylated pentitols and several fully acetylated hexitols have been analysed. Computation by iterative analysis and recourse to 250-MHz spectra were required in several cases. The vicinal coupling constants were used to determine the conformations of these compounds in solution. The planar zigzag conformation was found to be predominant only in those configurations ( arabino, manno) which do not possess parallel 1,3-interactions between acetoxyl groups on alternate carbon atoms. The other compounds were found to be mixtures of two or more conformers, none of which has the planar zigzag conformation, except in the case of hexa- O-acetylallitol. The conformations of alditols in the crystalline state and of the alditol acetates in solution are compared.

Conformations of acyclic sugar derivatives : Part III. 3.4,5,6,7-Penta-acetoxy- trans-1-nitro-1-heptenes

Conformations of acyclic sugar derivatives : Part III. 3.4,5,6,7-Penta-acetoxy- trans-1-nitro-1-heptenes

Chemotaxonomic aspects of the distribution of acyclic sugar alcohols in leafy liverworts I. Chemical evidence for the taxonomic position ofPlagiochila carringtonii(Balfour) Grolle

Chemotaxonomic aspects of the distribution of acyclic sugar alcohols in leafy liverworts I. Chemical evidence for the taxonomic position of<i>Plagiochila carringtonii</i>(Balfour) Grolle

Studies on conformation and reactivity—1 : Sugars with potential antiviral activity—4 The conformations of some acyclic sugar derivatives

An examination of the conformations adopted by acyclic sugar derivatives has been made. It is shown that 1,3-eclipsed rather than 1,2- gauche interactions are important in determining relative conformer population and that the observed conformer distribution, as determined by analysis of PMR spectra, is close to that calculated from consideration of non-bonded interactions.

Degradation of carbohydrates: Part IX. Penta- O-methyl- aldehydo- D-glucose

The acyclic sugar 2,3,4,5,6-penta- O-methyl- D-glucose ( 2) affords an equi-molecular mixture of the anhydrous and hydrated aldehyde forms in water at room temperature. In calcium hydroxide solution at 20°, 2 is completely degraded in 20 min to 3-deoxy-tetra- O-methyl- aldehydo- D- erythro-hex- trans-2-enose ( 3). The unsaturated aldehyde 3 is converted by dilute acid into 3,4-dideoxy-di- O-methyl- aldehydo- keto- D- glycero-hex- trans-3-enos-2-ulose.