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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of 1,2-cis-Configurated Glycosylphosphonates (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 25-34 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A synthesis of 1,2-cis-configurated, non-isosteric phosphonate analogues of aldose-1-phosphates is described. Treatment of 1-O-acyl-glycoses 1, 7, 13, and 19 with trialkyl phosphite in the presence of trimethylsilyl trifluoromethanesulfonate gave the 1,2-cis-configurated glycosylphosphonates 2, 4, 8, 10, 14, 16, 20, and 22 as the major anomers and the 1,2-trans-configurated glycosylphosphonates 3, 5, 9, 11, 15, 17, 21, and 23 as the minor anomers. The 1,2-cis-configurated phosphonates 4, 10, 16, and 22 were deprotected to give the (β-D-glucopyranosyl)phosphonate 6, the (β-D-mannopyranosyl)phosphonate 12, the (β-D-ribofuranosyl)phosphonate 18, and the (β-D-arabinofuranosyl)phosphonate 24, respectively, in high yields. The preferred formation of 1,2-cis-configurated phosphonates is explained by postulating an equilibrium between the anomeric phosphonium-salt intermediates (such as 25 and 26) and a stabilization of the cis-configurated salts through formation of a pentacoordinated species (such as 28).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690105
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  • 2
    Electronic Resource
    Electronic Resource
    L-Erythruronic Acid Derivatives as Building Blocks for Nucleoside Analogs. Synthesis of 4′-C-Aryl-D-ribonucleosides (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 2570-2582 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2, 3-O-Cyclohexylidene-L-erythruronic acid (6) available in 83% yield from D-ribonolactone (7), was treated with phenvlmagnesium bromide to give the D-ribo and L-lyxo derivatives 10 and 11 in high yields (Scheme 1 and 2). The diastereoselectivity depended on the temperature and mode of operation (Table 1). The absolute configuration of 10 and 11 was determined by correlation with (R)- and (S)phenylethanediol (17 and 16) respectively, excluding intramolecular hydride shifts during formation of 10 and 11. Reaction of 6 with methcoxymethoxyphenyllithium gave the lactones 18 and 19. The L-lyxo isomer 19 was transformed in high yields into the D-ribo lactone 18. Compound 10 was transformed into the adenosine analoge 24 by reduction with Diisobutylaluminium hydride, hydrolysis, acetylation and nucleoside synthesis according to Vorbrüggen (Scheme 3). Its structure was deduced from its UV., NMR. and CD. data and from those of the isopropylidene derivative 25. Similarly, 18 was transformed into the adenosine analog 29 and into the isopropylidene derivative 30.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650828
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  • 3
    Electronic Resource
    Electronic Resource
    Deoxy-nitrosugars. 9th communication8th Communication: [1]. Chain elongation of 1-C -nitroglycosyl halides by substitution with some weakly basic carbanions (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 2236-2241 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1-C-nitroglycosyl chloride reacted with the anions form 2-nitropropane, nitromethane, and diethyl malonate, to give the chain-extended products 2 (81%), 5 (72%), and 6 (83%), respectively. Treatment of the 1-C -nitroglycosyl bromide 7 by the lithium salt obtained form 8 gave the dodecodiulose derivative 9 (76%). Th β-D-configuration of 2 and 9 was inferred form their NMR and CD spectra. Treatment of 2 and 9 with sodium sulfide gave the enol ethers 3 (96%) and 10 (92%), respectively. The (Z)-configuration of 10 was deduced form the configuration of its hydrogenation product 11.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670828
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  • 4
    Electronic Resource
    Electronic Resource
    Deoxy-nitrosugars 8th communication7th Communication: [1]. Convenient preparation of 1-C-nitroglycosyl chlorides. Halonitro ethers from hydroxy oximes (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 1568-1571 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Partially protected 4- or 5-hydroxy-sugar oximes were transformed into 5- or 6-membered 1-C-nitroglycosyl chlorides, respectively, by reaction with NaOCl under phase-transfer conditions. With the exception of the oxidation of the gluco-derivative 1 giving the anomers 6 and 7, the reactions were completely diastereoselective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670622
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  • 5
    Electronic Resource
    Electronic Resource
    Deoxy-nitrosugars. 11th Communication10th Communication: [1].. Reactions of 1-C-nitroglycosyl halides and 1-C-nitroglycosyl sulfones with dialkyl-phosphite anions: Nucleophilic attack vs. single-electron transfer (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 997-1009 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of the chloro-nitro-ribofuranose 7 with KPO(OMe)2 gave the O-amino phosphate 8 (5 %) and the nitrile 9 (62 %). Compound 9 was also obtained by the reaction of 8 with KPO(OMe)2, and its structure was established by X-ray analysis. Treatment of the chloro-nitro-mannofuranose 10, the bromo-nitro-ribofuranose 14, or the bromo-nitro-mannofuranose 16, respectively, with the K or Na salt of HPO(OMe)2 lead also to O-amino phosphates and nitriles. The (1-C-nitroglycosyl)phosphonate 22 was obtained (21 %) together with the nitrile 21 (51 %) from the chloro-nitro-mannofuranose 10 and KPO(OEt)2. The reaction of the 1-C-nitroglycosyl sulfone 25 (NO2-group endo) with KPO(OEt)2 gave the (1-C-nitroglycosyl)phosphonate 22 (61%) and the nitrile 21 (11 %), whilst the anomeric sulfone 26 (NO2-group exo) gave 22 (15 %) and 21 (58 %). In the presence of [18] crown-6, a mixture of the anomers 25 and 26 gave the (1-C-nitroglycosyl)phosphonate 22 in 67 % yield together with 21 (13 %). These findings are rationalized as the result of a competition between a nucleophilic attack of the dialkyl-phosphite anions on the NO2-group leading ultimately to the nitrile 21 and a single-electron transfer reaction leading to the (1-C-nitroglycosyl)phosphonate 22.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680426
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  • 6
    Electronic Resource
    Electronic Resource
    Deoxy-nitrosugars 12th communication11th Communication: [1]. Synthesis of isosteric mono-phosphonate analogues of β-and α-D-fructose 2,6-bisphosphate (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 751-760 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A synthesis of the isosteric mono-phosphonate analogues 2a and 19 of the β-and α-D-fructose 2,6-bisphosphate, respectively, is described. Chain elongation of the 1-deoxy-1-nitro-D-arabinose 3 (Scheme 1) by a Henry reaction with paraformaldehyde followed by protection of the resulting alcohol (methoxymethyl ether) and a radical-chain substitution by nitromethane anion gave the key intermediates, the gluco-anhydroalditol 6 and the manno-anhydroalditol 7. These products equilibrated under basic conditions. Conversion of 7 to the aldehyde 9, Abramov reaction of 9 with diphenyl phosphite followed by deoxygenation according to Barton gave the phosphonate 11 (Scheme 2). Selective hydrogenolysis of 11, phosphorylation and deprotection gave 2 which was converted to the tetrasodium salt 2a. Similarly, 6 was transformed into the isosteric phosphonate analogue 19 of the α-D-fructose 2,6-bisphosphate (Scheme 3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690402
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