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  • Articles  (29)
  • Chemistry  (28)
  • Polymer and Materials Science  (3)
  • Thermodynamics
  • General Chemistry
  • 1980-1984  (12)
  • 1975-1979  (17)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 9 (1983), S. 145-170 
    ISSN: 1432-1017
    Keywords: Viroids ; Thermodynamics ; Kinetics ; Hydrodynamics ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Viroids are an independent class of plant pathogens which are distinguished from viruses by the absence of a protein coat and by their unusually small size. They are single-stranded circular RNAs composed of about 360 nucleotide residues. Sequence analysis and physicochemical studies of the potato spindle tuber viroid (PSTV) have shown that, as a result of intra-molecular base pairing, viroids form a unique rod-like secondary structure which is characterized by a serial arrangement of double-helical sections and internal loops. There is no indication for an additional tertiary structure because all parts of the molecule are freely accessible to ligand interaction. During the denaturation all of the native base pairs of viroids are dissociated in one highly cooperative transition, and in the same process very stable hairpins which are not present in the native structure are newly formed. Most of the properties of the structure and structural transitions of PSTV have been found also in citrus exocortis viroid, chrysanthemum stunt viroid and four different viroid-like RNAs associated with the cadang-cadang disease. The close similarity between these viroids is more expressed in the overall structure and in thermodynamic and functional domains than in the primary sequence. The stiffness of all viroids can be described by an unique persistence length of 300 å. Characteristically, regions of premelting, regions of stable hairpins, and the sequence UACUACCCGGUGG which is opposite to one of the stable hairpins, are the most conservative sequences in the molecules. Current hypotheses about the function of viroids are discussed on the basis of their structural and thermodynamic features. The suggestion that viroid RNA has features similar to DNA has been supported by the finding that they are replicated in vitro by the DNA-dependent RNA polymerase II of the host plant. The highly conserved sequence in viroids mentioned above corresponds very closely to a segment at the 5′-end of the small nuclear RNA U1 of eukaryotes. Because this segment is discussed in recent models, to be involved in the splicing process, a hypothesis is proposed in which viroids interfere with the splicing process leading to a pathogenic misregulation of mRNA processing.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 324 (1982), S. 537-544 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Substituted Phosphonates. 39. Methane-diphosphonic Esters by U.V.-Induced Michaelis-Becker-ReactionDibromomethane resp. chlorbromomethane reacts with sodium dialkyl phosphite in heptane-/liq.NH3 or in liq. NH3 by u.v. irradiation at low temperatures to give in good yields methane diphosphonic acid tetraalkylesters 1. In the same manner with sodium diethyl thionophosphite the corresponding methane-bis-thiophosphonic acid tetraethylester 4 is obtained.
    Additional Material: 2 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 324 (1982), S. 545-549 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Substituted Phosphonates. 40. 1-Trimethylammonium-1-diethylphosphono-1-cyanomethylid, a Stable N-YlidDiethyl-1-dimethylamino-1-cyanomethanephosphonate 4 can be alkylated on nitrogen to the quarternary ammoniumsalts 5, which by C-deprotonation gives the stable N-ylid 8. The N-ylid 8 behaves inert against carbonyl compounds and acylating agents, but can be C-alkylated and  -  involving an ester-dealkylation  -  C-chlorinated.
    Additional Material: 1 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 320 (1978), S. 389-394 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Substituted Phosphonates. XXXI. The Reaction of N,N,N′,N′-Tetramethyl Chloroformamidinium Chloride with P(III) CompoundsN,N,N′,N′-Tetramethyl chloroformamidiniumchloride (4) does not react with triethyl phosphite (TEP) or isopropyl diphenylphosphinate to give the expected bisphosphoryl derivatives 7 and 11, respectively, but primarily the monophosphorylated amidinium salts 6 and 10 respectively. The phosphine oxide 10 is stable, while 6 undergoes an elimination of ethyl chloride to the betain 8. Even under more drastic conditions the reaction of 4 or 8 with TEP does not lead to the expected bis(dimethylamino)bisphosphonate 7, but to the monoaminated bisphosphonate 1, involving a reduction step. Similar reduction has been observed under mild conditions in Michaelis-Arbusov reaction of dichloromethylenimonium chloride, yielding the expected trisphosphonate 2 and the bisphosphonate 1 as a by-product.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 325 (1983), S. 437-445 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Substituted Phosphonates. 43. Synthesis and Reactivity of 1,2,3,4-Tetrahydroisochinolin-1-phosphonatesN-Alkyl- and N-arylsubstituted 1,2,3,4-tetrahydroisochinolin-1-phosphonates 1 have been synthesized from the corresponding 3,4-dihydroisochinoliniumbromides 7 and triethyl-phosphite. The N-unsubstituted 1,2,3,4-tetrahydroisochinolin-1-phosphonate 10 is available starting from the 1,2,3,4-tetrahydroisochinolin-1-phosphonic acid by esterification with triethylformate and splitting off the formyl group of the primarily formed N-formyl derivative 14. - N-Quarternated tetrahydroisochinolines 19 and the 1-phosphorylated derivatives 17, respectively react with triethyl-phosphite in an unexpected way by dealkylation and not by splitting off the isochinolinring. - By Horner-synthesis with 1 the 1-aralkylidene-isochinolines 23 are available in moderate yields.
    Additional Material: 4 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 323 (1981), S. 939-950 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactions of 2-Aryloxy-s-trithianes2-Aryloxy-s-trithianes 4 had been prepared from 1-tosyl-imino-1-SIV-1,3,5-trithiane and phenolates. - By self-condensation of 4 1,5-bis-(trithianyl)-1,3,5-trithiapentane 5 and triphenyl-orthoformate 7 are formed, accompanied by further products, which had been isolated in pure state and identified unambiguously by H-n.m.r. and mass-spectra. In the presence of acids the 2-aryloxy-s-trithianes 4 react with nucleophilic aromatic compounds such as phenoles, N,N-dimethylaniline, pyrrole, indole, and thiophenes to give the C-trithianylated products. With mercaptanes 2-alkylthio-s-trithianes are formed.
    Additional Material: 1 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 34 (1983), S. 153-153 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 343-346 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 320 (1978), S. 128-132 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: O,O- and S,S-Acetals of FormylphosphoniumsaltsFor the synthesis of O,O- resp. S,S-acetals (4) of formylphosphoniumsalts, which are not known as free formylderivatives, is described a simple method, consisting in reaction of tert. phosphin with orthoester and acetyl-halide. O,O-Diarylacetals of the type 4 can be synthesized from tert. phosphine and diaryloxychlormethane.
    Additional Material: 1 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 317 (1975), S. 798-806 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphonsäuremonoalkylester bzw. Phosphonsäuren reagieren mit Epoxiden zu Phosphonsäure-alkyl-β-hydroxyalkyl- 5 bzw. -bis-β-hydroxyalkylestern 9 oder zu höhermolekularen Polyglykolestern. Durch intramolekulare Umesterung entstehen aus 5 bzw. 9 beim Destillieren unter Abspaltung von Alkohol bzw. Glykol cyclische Phosphonsäureester 6 bzw. 11.
    Additional Material: 3 Tab.
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