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'Carbohydrates' in keywords Facet   section ZfN Section B  [X]
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1Author    TalebH. Al-TelRequires cookie*
 Title    Carbohydrates to Pyrano-Furanoids: New and Regioselective Palladium-Catalyzed Syntheses of Tetrasubstituted Furanoids from Carbohydrate Scaffolds  
 Abstract    A new strategy for the asymmetric syntheses of polysubstituted pyrano-furanoids using allylic sulfates derived from carbohydrate precursors and the dianion of diethoxycarbonyl acetone, catalyzed by Pd(0), is described. 
  Reference    Z. Naturforsch. 55b, 657—660 (2000); received March 27 2000 
  Published    2000 
  Keywords    Dihydrofuran, Carbohydrates, Palladium 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0657.pdf 
 Identifier    ZNB-2000-55b-0657 
 Volume    55 
2Author    R. En, C. Su, PetraD. Örrb, M. Artin, K. Ühnb, ClausK. Rieger0, M. Ikhael, Y. A. Ntip In DRequires cookie*
 Title    Chiral Pool Synthesis of 4a-Substituted Carbocyclic Cyclopentanoid Nucleoside Precursors, I  
 Abstract    A suitable protected D-ribono-1,4-lactone derivative has been used for the straightforward chiral pool synthesis of cyclopentanoid nucleoside precursors. Thus, epoxidation followed by deoxygenation or regioselective ring opening led to nucleoside precursors modified at the positions C(4), C(4a) and C(4,4a) as well as side-chain modified derivatives. The structures of the key intermediates were determined by X-ray analyses. 
  Reference    Z. Naturforsch. 54b, 1068—1078 (1999); received May 21 1999 
  Published    1999 
  Keywords    Nucleosides, Carbohydrates, X-Ray Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1068.pdf 
 Identifier    ZNB-1999-54b-1068 
 Volume    54 
3Author    Z. NaturforschRequires cookie*
 Title    Chiral Pool Synthesis of 4a-Substituted Carbocyclic Cyclopentanoid Nucleoside Precursors, II  
 Abstract    Suitable protected 4,4a-anhydro-cyclopentane derivatives have been used for the straight­ forward of cyclopentanoid nucleoside precursors. Thus, by simple transformations nucleoside precursors modified at the positions C(4), C(4a) and C(4,4a) as well as side-chain modified derivatives were accessible. The structures of the key intermediates were determined by x-ray analyses. 
  Reference    Z. Naturforsch. 54b, 1079—1091 (1999); received May 27 1999 
  Published    1999 
  Keywords    Nucleosides, Carbohydrates, X-Ray Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1079.pdf 
 Identifier    ZNB-1999-54b-1079 
 Volume    54 
4Author    ClemensVon Sonntag, Miral Dizdaroglu, Dietrich Schulte-FrohlindeRequires cookie*
 Title    y-Radiolysis of Cellobiose in N20-saturated Aqueous Solution Part II. Quantitative Measurements. Mechanisms of the Radical-induced Scission of the Glycosidic Linkage  
 Abstract    The y-radiolysis of cellobiose (10 -2 M) in N2O saturated aqueous solution has been investigated and the G-values of the following 21 products containing six or less C-atoms have been measured (G-values in parentheses): glucose (2.1), gluconic acid (0.70), 4-keto-glucose (0.07), 5-keto-glucose (0.05), 4-deoxy-glucose (0.27), 5-deoxy-gluconic acid (0.18), 2-deoxy-gluconic acid (0.13), 3-deoxy-4-keto-glucose (0.23), 2-deoxy-5-keto-glucose (0.34), 4-deoxy-5-keto-glucose (0.14), 6-deoxy-5-keto-glucose (0.02), arabinose (0.07), ribose (0.015), 2-deoxy-ribose (0.17), 3-deoxy-pentulose (0.01), erythrose (0.015), threose (0.015), 2-deoxy-tetrose (0.01), butanone-(2)-diol(1.4) (0.01), dihydroxyacetone (0.01), carbon monoxide (> 0.02). The formation of the major part (98%) of the measured products could be explained on the base of the following assumption: The first step of reaction sequence is abstraction of H atoms from C-H bonds of the cellobiose by OH radicals. Radicals at C-l', C-5' and C-4 and their successors undergo in a second step four types of reactions: hydrolysis, re-arrangement and H2O and CO elimination. In a third step the transformed radicals give rise to products by disproportionation reaction. Only two products out of 16 predicted under the above assumption are not observed. G-values for the attack at C-l', C-5' and C-4 are 1.4, 0.6 and 0.3 respectively. 
  Reference    (Z. Naturforsch. 31b, 857—864 [1976]; received February 25 1976) 
  Published    1976 
  Keywords    Carbohydrates, Radical Reactions, y-Radiolysis, Cellobiose, Glycosidic Linkage 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0857.pdf 
 Identifier    ZNB-1976-31b-0857 
 Volume    31 
5Author    Heinz-Peter Schuchmann, Rita Wagner, Clemens Von SonntagRequires cookie*
 Title    7-Radiolysis of 2'-Deoxycytidine-5'-phosphate in Deoxygenated Aqueous Solutions. OH Radical-Induced Alterations at the Sugar Moiety  
 Abstract    In order to elucidate some aspects of the mechanism of radical-induced strand break formation in DNA, the y-radiolysis of N20-saturated aqueous solutions of 2'-deoxycytidine-5'-phosphate has been studied as a model system. At pH 4 it has been observed that upon OH attack at the sugar moiety phosphate (G ^ 0.6) and cytosine (G = 1) are released and the following cytosine-free sugars are formed: 2,5-dideoxypentos-3,4-diulose, 1 (G = O.22), 2-deoxy-pentos-4-ulose, 2 (G = 0.1s), 2-deoxy-pentos-4-ulose-5-phosphate, 3 (G=0.06), 2-deoxypentonic acid-5-phosphate and its lactone, 5 (G «0.5). Some 2-deoxyribose-5-phosphate, 4 is also formed. Upon addition of H2O2 (up to 10 -2 M) prior to irradiation, G(l) is drastically reduced without giving rise to another cytosine-free product. G(3) increases at the expense of G(2). G (4 + 5) also increase upon H2O2 addition. The formation of these products and the change of their G values as a function of H2O2 concentration are discussed in the light of well-documented radical reactions of carbohydrates and related compounds. The precursor of 1 has been considered to be the radical at C-3', that of 2 and 3 the radical at C-4' and that of 5 the radical at C-l'. Product 4 is thought to arise from a radical-induced destruction of the cytosine moiety. These primary radicals which may undergo rearrangement, or eliminate phosphate, are readily oxidised by H202, a reaction which leads to the change of product distribution mentioned above. 
  Reference    Z. Naturforsch. 38b, 1213—1220 (1983); received June 27 1983 
  Published    1983 
  Keywords    Free Radicals, Radical Cations, Carbohydrates, DNA Model 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-1213.pdf 
 Identifier    ZNB-1983-38b-1213 
 Volume    38 
6Author    Requires cookie*
 Title    Radiation Chemistry of DNA-Model Compounds, VII* On the Formation of 5-Deoxy-D-erythro-pentos- 4-ulose and the Identification of Twelve Further Products from y-Irradiated Aqueous Solutions of Ribose-5-phosphate  
 Abstract    L o t h a k S t e l t e r , C l e m e n s v o n S o n n t a g , a n d D i e t r i c h S c h u l t e -F r o h l i n d e Different mechanisms are considered to explain the formation of 5-deoxy-D-erythro-pentos-4-ulose in the y-radiolysis of ribose-5-phosphate in aqueous solution. On the basis of deuterium labelling experiments one mech­ anism involving an enol as an intermediate could be excluded. The identification of twelve further radio-lysis products from ribose-5-phosphate is reported. 
  Reference    (Z. Naturforsch. 30b, 656—657 [1975]; received February 19 1975) 
  Published    1975 
  Keywords    y-Radiolysis, Ribose-5-phosphate, Carbohydrates, Radical Reactions, Radical Cations 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0656_n.pdf 
 Identifier    ZNB-1975-30b-0656_n 
 Volume    30 
7Author    WilhelmV. Dahlhoffd, Karin Radkowskia, Ingo Dierkingb, Peter ZugenmaierbRequires cookie*
 Title    Amphiphilic Carbohydrate-Based Mesogens, 12 [1] High-Yield Synthesis of Mesogenic l-O-Alkanoyl-D/L-Xylitols  
 Abstract    The equilibrium mixture of 1,2:3,4-and l,3:2,4-di-0-ethylboranediyl-D /L-xylitols 1 and 1' obtained on reaction o f three equivalents of xylitol with two equivalents of triethylboroxin, reacts with alkanoyl chlorides (heptanoyl-dodecanoyl) to give equilibrium mixtures of the O-ethylboranediyl protected l-O-alkanoyl-D.L-xylitols 2,2' after vacuum distillation. Depro­ tection of the latter affords the title amphiphilic esters 3 which melt to give the smectic A liquid-crystalline phase. 
  Reference    Z. Naturforsch. 51b, 1229—1234 (1996); received April 26 1996 
  Published    1996 
  Keywords    Carbohydrates, Amphiphiles, Liquid Crystals (Smectic), 1-0-A lkanoyl-D, L-X ylitols, X-Ray 
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 TEI-XML for    default:Reihe_B/51/ZNB-1996-51b-1229.pdf 
 Identifier    ZNB-1996-51b-1229 
 Volume    51