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  • Inorganic Chemistry  (3)
  • Polymer and Materials Science  (2)
  • 72.20.-i
  • 78.20.-e
  • 1980-1984  (5)
  • 1981  (5)
Collection
Publisher
Years
  • 1980-1984  (5)
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 1337-1382 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have synthesized and studied the CD spectra of five new double-stranded RNA polymers: poly[r(A-G)·r(C-U)], poly[r(A-U-C)·r(G-A-U)], poly[r(A-C-U)·r(A-G-U)], poly[r(A-A-C)·r(G-U-U)], and poly[r(A-C-C)·r(G-G-U)]. Together with previously published spectra of seven other RNA sequences, the spectra of these new sequences provide a library sufficient to approximate the spectra of all other RNA sequences by first-neighbor formulas and, in addition, give four spectra with which we may test the validity of first-neighbor approximations. (1) We find that the spectra of RNA sequence isomers are very different, but that the spectra essentially do obey first-neighbor relationships. (2) We have derived tentative first-neighbor assignments of negative bands at about 295 and 210 nm in the CD spectra. (3) A test of spectral independence shows that among the 12 polymer spectra there are at least seven significant independent spectral shapes, one less than the eight needed to give the most accurate spectral analysis of an unknown RNA sequence for its first-neighbor frequencies. (4) Spectra are calculated for RNAs of random base composition, approximating natural RNAs having complex sequences. (5) A T-matrix of spectral components assigned to the first-neighbor base pairs is derived from 10 of the spectra. This matrix allows an estimation of the CD spectrum of any other known RNA sequence or an analysis of the spectrum of an unknown sequence for its distribution of first-neighbor base-pair frequencies. (6) Test analyses of two of the synthetic polymers and of two natural RNAs set a probable limit on the accuracy of first-neighbor frequency determinations using this T-matrix. (7) Finally, we summarize in an appendix the melting temperatures for all the RNA and corresponding DNA sequences; it appears that the Tm values of both DNAs and RNAs approximately obey first-neighbor relationships.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2834-2843 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosylhydrazines, 5. Synthesis of pyrazole-, Pyrazolo[3,4-d]pyrimidine-, and 1H-1,2,4-Triazol-Nucleoside 5′-amide Derivatives via Riburonamide HydrazonesIn a single step reaction the 3,5-dimethylpyrazole nucleoside-5′-amides 6a,c, the functionally substituted pyrazole nucleoside-5′-amides 9a and 10b, and the 1H-1,2,4-triazol-nucleoside-5′-amide 18 were obtained regio- and stereoselectively from the riburonamide hydrazones 4a-c.9a and 10b were transformed into the unprotected pyrazolo[3,4-d]pyrimidine nucleoside-5-amide 14a and 15b, derivatives of allopurinol riboside. likewise the ethylamide 20 of virazole-5′-acid was synthesized from 18.
    Notes: Aus den Riburonamid-hydrazonen 4a-c wurden in einer Eintopfreaktion regio- und stereoselektiv die 5′-Säureamid-Derivate des 3,5-Dimethylpyrazol-nucleosids 6a,c, der funktionell substituierten Pyrazol-nucleoside 9a) und 10n) und des 1H-1,2,4-Triazole-nucleosids 18 direkt aufgebaut. Als Allopurinolribosid-Derivate wurden aus 9a und 10b die ungeschützten pyrazolo[3,4-d]pyrimidin-nucleosid-5′-säureamide 14a und 15b hergestellt. Entsprechend wurde aus 18 das Ethylamid 20, der Virazol-5′-säure erhalten.
    Additional Material: 1 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 740-745 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Acetals of L-Rhamnose with Lithium-organic Compounds New Syntheses of Mycaral, Olivomycal, and Methyl 2,3,6-Trideoxy-α-L-erythro-hex-2-enopyranosideMethyl α-L-mycaroside (6a) is obtained from the dideoxy-uloside 2) by Grignard addition. the benzylidene rhamnoside (1a) reacts with methyllithium to give in only one step mycaral (4) (21%) and olivomycal (5) (72%). With lithiumdiisopropylamide 1a yields the unsaturated sugar 3a.
    Notes: Methyl-α-L-mycarosid (6a) wird aus dem Didesoxy-ulosid 2 durch Grignard-Addition erhalten. Das Benzylidenrhamnosid 1a reagiert mit Methyllithium in einem schritt zu Mycaral (4) und Olivomycal (5). Mit Lithiumdiisopropylamid erhält man hingegen aus 1a den ungesättigten Zucker 3a.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1192-1195 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Acetals of Sugars with Organolithium Compounds A Simple Synthesis of 4,6-Dideoxy-α-D-erythro-hexopyranos-3-ulose1,2:3,4-Di-O-isopropylidene-β-L-arabinose (3) reacts with lithium diisopropylamide to give the 4-deoxy-4-eno sugar 4. After its oxidation a stereospecific 1,4-addition by methyllithium/copper (I) iodide yields the 4,6-dideoxy-3-ulose 6.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 983-989 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A cage model has been presented to describe the kinetics of recombination of radicals in solid polymer. The theory includes Torrey's treatment for jump diffusion and radiative boundary condition in the diffusion equation to account for the hindrance to the diffusion of macroradicals and the finite cage process of recombination reaction, respectively. The result has been applied to the interpretation of data on the decay of allyl radical in irradiated polyethylene.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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