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  • Chemistry  (7,322)
  • General Chemistry  (1,623)
  • Inorganic Chemistry  (1,011)
  • Wiley-Blackwell  (7,322)
  • 1970-1974  (5,468)
  • 1950-1954  (1,854)
  • 1971  (5,468)
  • 1950  (1,854)
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  • 1970-1974  (5,468)
  • 1950-1954  (1,854)
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  • 101
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a study of A-B type block copolymers of γ benzyl-L-gultamate and β-benzyl-L-aspartate use has been made of the observations: (1) that for poly aspartate esters the chemical shifts of the α-CH and NH resonances are sensitive to the helix sense, (2) that in both helical and random coil conformations the same resonances of poly-γ-benzyl-L-glutamate are well separated from those of poly aspartates. Since the sense of poly-β-benzyl-L-aspartate is very sensitive to the inclusion of γ-benzyl-L-glutamate residues, the degree of overlap between the blocks can be studied by monitoring the helix sense of the aspartate. The ability of the NMR method to make separate observation of the two blocks removes the necessity of relying on an overall ORD parameter such as b0. The copolymers studied include those having lefthanded, righthanded, and mixed-sense aspartate, corresponding to differing degrees of overlap.
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  • 102
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    Biopolymers 10 (1971), S. 2615-2617 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 103
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    Biopolymers 10 (1971), S. 2629-2634 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 104
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    Biopolymers 10 (1971), S. 2649-2649 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 105
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    Biopolymers 10 (1971), S. 11-20 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes a theoretical and experimental analysis of the binding of magnesium ions to yeast, ribosomes. In the theoretical considerations the interactions between charges located on a macroion are included. In the calculations these interactions result in a term, in which both the charge and the radius of the macroion are accounted for. It appears that on dissociation of the ribosomes both the charge and the radius change, but in such a way, that the term, which accounts for the electrostatic interactions, remains constant. As a consequence the dissociation can lie neglected in the analyses of the binding experiments. Our experiments indicate that two binding reactions between ribosomes and magnesium ions occur. The endpoints of these reactions correspond to about 0.40 and 1.0 equivalent magnesium per ribosomal phosphate, respectively. The pK values are about 3.8 and 2.2, respectively. The experimental results indicate that the effect, of monovalent cations can be explained as a pure ionic strength effect, though the binding of monovalent cations could not be excluded completely.
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  • 106
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    Biopolymers 10 (1971), S. 89-106 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Raman spectra of poly-γ-benzyl-L-glutamate, poly-L-leucine, poly-L-valine, and poly-L-serine are reported. For the α-helical polymers, the conformationally sensitive amide I, II, and III modes are observed in the Raman as, well as the infrared. For the β form, the Raman effect, supplies the infrared inactive inphase motion which is useful for the determination of a parallel or antiparallel chain alignment. Modes characteristic of the specific polypeptide are also observed which are insensitive to conformation.
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  • 107
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    Biopolymers 10 (1971), S. 47-68 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helical stability of a variety of DNA samples, ranging in base composition from 0 to 72 mole-% GC, has been studied by heat denaturation at neutral pH in increasing concentrations of LiCl, NaCl, KCl, CsCl, Li2SO4, and K2SO4. The variation of melting temperature with average base composition, dTm/dXGC, was found to decrease drastically in the concentrated salt media, e.g., from 41°C in 0.006M LiCl to 29°C in 3.2M LiCl, and from 39°C in 0.003M Li2SO4 to 18°C in 1.6M Li2SO4. At the same time, the thermal transition is much more cooperative in the concentrated salt solutions than at low ionic strength. Indeed, at limiting salt concentrations, the transition breadth seems to reach a minimum value irrespective of the compositional heterogeneity of the DNA samples. Attempts to correlate the observed decrease of dTm/dXGC with predicted changes in the enthalpy of melting, deduced from a simple theoretical treatment, experimental data on the binding of counterions and water to DNA, and experimental data on thermal denaturation, were unsuccessful. However, the strongly reduced composition dependence of the melting temperature can be understood in terms of a destabilizing effect of the concentrated salt media on GC-base pairs. It is suggested, though not proven, that the destabilization involves the displacement of water molecules from the DNA helix.
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  • 108
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    Biopolymers 10 (1971), S. 329-336 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal helix-coil transition of poly(γ-benzyl L-glutamate-co-ε-carbobenzoxy-L-lysine) copolypeptides was studied in solvent mixtures of different compositions. The cooperativity parameter v changes linearly with polymer (and solvent) composition, whereas the heat of the transition shows a very pronounced minimum as a function of polymer composition. This minimum cannot be due only or mainly to the solvent changes and must be attributed to the effect on the transition of the side chains of the polypeptides.
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  • 109
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-(l)-Menthyl D- and L-aspartates were prepared by a fusion reaction of N-phthalyl D- and L-aspartic anhydrides with l-menthol, followed by hydrazinolysis. The monomers were then polymerized to poly[β-(l)-menthyl D- and L-aspartates] by the N-carboxyanhydride method. These polymers were soluble in many organic solvents, such as diethyl ether, tetrahydrofuran, chloroform, n-bexane, and dioxane. From the results obtained by a study of the optical rotatory dispersions and circular dichroisms, poly [β-(l)-menthyl D-aspartate] was found to be a β form structure in solution. On the other hand, poly[β-(l)-menthyl L-aspartate] was a random-coil structure. These results suggest that the asymmetry of the l-menthyl chromophore in the side chain interacts with the polypeptide main chain and causes an extraordinary optical rotation.
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  • 110
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diffusion, sedimentation, and viscosity behavior of native DNA has been studied as a function of molecular weight absolutely determined by diffusion and sedimentation measurements between 106 and 20 × 106 Daltons. Only data for monodisperse subfractions of the polydisperse DNA samples investigated have been compared. They were derived by means of calculations based on individual sedimentation constant distribution and polymer parameters. The inconstancy of these parameters for the semi-rigid DNA molecules over the range of different sub-fractions of the polydisperse samples has been taken into account. A detailed description of the corresponding mathematical background as well as of the diffusion measurements has been given in the two preceding papers. For the homologous series of monodisperse native DNA molecules, three-parameter equations have been determined representing the s0-[η], s0-M, and [η]-M relations as well as the D0-s0 and D0-M interdependence over the entire molecular weight range of interest. Furthermore a simple equation is given describing the molecular weight dependence of the Mandelkern-Flory-Scheraga parameter β in terms of s0 and [η]. The asymptotic value β∞ has been determined, primarily by measurements at finite molecular weights, to be 2.39 × 106, resulting in β values near 2.50 × 106 at M = 108 Daltons. The hydrodynamic properties of our two calf thymus DNA samples of highest molecular weight proved to be influenced by residual protein interactions resulting in a more compact conformation. Further data are given demonstrating the influence of the individual polydispersity of the investigated samples on diffusion constant and molecular weight averages.
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  • 111
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titration of an aqueous solution of sodium poly-L-glutamate with a strong acid usually produces turbidity and precipitation before the equivalence point is reached. In 1M sodium p-toluenesulfonate and 1M sodium methylcyclohexanesulfonate aggregation was delayed for days to months. In very concentrated tetra-n-butylammonium chloride and bromide the polymeric acid dissolved and could be titrated with NaOH. However, potentiometric titration curves in these solutions did not yield information (by way of plots of apparent pK versus the degree of neutralization) about the helix-to-coil transition of the polymer. It was argued in addition that the apparent pK of a weak polyelectrolyte should not be calculated from titrations in concentrated salt solutions since it is a mixed or composite quantity. It contains not only the effect of the salt on the dissociation of the weak electrolyte but its effect on the activity coefficient of hydrogen ions as well.Circular dichroic spectra were therefore measured a t various degrees of neutralization of poly(L-glutamic acid) in a number of aqueous salt solutions and mixtures of organic solvents with water. It was found that the undissociated polymer in the concentrated methylcyclohexanesulfonate and quaternary ammonium halide solutions had the spectrum of a right-handed α helix. The n → π* band at 222 mμ was used as a measure of the fraction of polymer in the helical conformation. The value of - Δε for the undissociated polyacid in these organic electrolyte solutions was 11.4. By means of this value and a number of assumptions, the fraction of helix (fh) as a function of α, the degree of polyacid neutralization, was calculated for the different solvent mixtures. An empirical equation was used to describe the variation of fh with α, fh = 1/(1 + e-a+bα), in which b represents the degree of cooperativeness of the transition, and a is a measure of the effect of the medium on the onset of the transition. The values of b did not differ very much from one another, suggesting that the cooperativeness of the transition was not sensitive to changes in the medium. On the other hand, the value of a (or its equivalent, the value of α at the halfway point in the transition) was more dependent on the solvent. Comparisons of these results with those of some other workers were made by means of the empirical equation.
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  • 112
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    Biopolymers 10 (1971), S. 411-416 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 113
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    Biopolymers 10 (1971), S. 417-419 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 114
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    Biopolymers 10 (1971), S. 399-410 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of temperature on the binding of 9-aminoacridine and of proflavine to E. coli DNA in 10-3M NaCl solution has been determined by a spectrophotometric technique. The inadequacy of the expression normally used for the determination of the extent of binding is discussed with reference to measurements at temperatures above which dissociation of the double helix occurs. A method of determining the relative extents of binding to native and denatured DNA at elevated temperatures is described.
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  • 115
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    Biopolymers 10 (1971), S. 421-421 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 116
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    Biopolymers 10 (1971), S. 423-423 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 117
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quantum-mechanical calculations by the PCILO method on the conformation of amino acid residues of proteins have been extended to the valyl, leucyl, and isoleucyl residues. In distinction to the earlier “empirical” computations, the quantum-mechanical results indicate very similar energy contours for the stable conformations of the three residues. Their general outline is also similar to that of the alanyl residue, although reduced by about 25%. Contrary to the “empirical” computations, the present results predict that the region corresponding to the α-helix should be one of great stability for the three residues and in particular for the valyl residue. The quantum-mechanical results are in excellent agreement with the experimental conformations of the aliphatic residues in lysozyme and myoglobin. Their prediction as to the ready availability of the valyl residue in the α-helical conformation agrees moreover with Ptitsyn's statistical evaluation of the participation of this residue in the inner turns of the helical regions in six globular proteins. The maximum conformational space allowed for the aliphatic residues is somewhat smaller than that allowed for the aromatic ones, while the minimum conformational space (region of stability common to all the residues) is similar in both groups.
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  • 118
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    Biopolymers 10 (1971), S. 513-522 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil transition of DNA of various base compositions has been followed by measuring the heat capacity and the ultraviolet absorption as a function of temperature through the transition region. The results of these measurements indicate that the transition enthalphy ΔH for a given pH value and salt concentration depends considerably on the base composition of the various DNA samples. The values of the transition enthalpies vary from ΔH = 7.73 kcal/mole base pair (MBP) for 31% GC base pairs to ΔH = 8.52 kcal/MBP for 72% GC base pairs. The results of the heat capacity measurements are discussed in relationship to the theoretical models suggested by various authors. Some peculiarities of the measured heat capacity versus temperature curves are reported. The correlation between these peculiarities and the results of the transcription experiments of DNA is discussed.
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  • 119
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    Biopolymers 10 (1971), S. 711-719 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly-L-histidine (PLH) films at different degrees of protonation were produced mid subjected to infrared spectroscopic investigation (range 4000-650 cm-1). In addition, the N-deuterated film spectra were plotted. The amide II and III bands show that the peptide group is present in the trans form. The amide I and II bands show that at 0% and 50% protonation the PLH occurs as an α-helix and at 100% protonation as a random coil with some ranges in β structure. At 0% and 50% protonation, no hydration water is bound to the backbone. At 0% protonation all NH groups are linked to each other or to water molecules via hydrogen bonds. At 50% protonation NH+ċN bonds form between the imidazole rings. These protons are present in continuous energy level distribution. Such bonds with tunneling protons are extremely polarizable and between these bonds may act proton dispersion forces. The Cl- ions are bonded to the NH groups of the imidazole groups. The hydration water is bonded to the Cl-- ions and to the NH groups. At 100% protonation, hydration water is bonded also to the CO groups of the backbone. The NH groups of the backbone, like those of the rings, endeavor especially in the dry state to bond to the Cl- ions. This leads to a strong steric constraint of the random coil.
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  • 120
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    Biopolymers 10 (1971), S. 721-737 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational transition between the two helical forms I and II of poly-L-proline serves as an experimental model for the study of the kinetic, behavior of cooperative systems. The slow I ⇌ II conversion after a sudden perturbation of the solvent composition was followed polarimetrically. The dependence of the mean relaxation times on chain length and the degree of conversion was compared with Schwarz's theory. In addition, a description of the entire relaxation curves was possible in three special cases: all-or-nothing, small perturbations of the I ⇌ II equilibrium in long chains, and conversions which start off with molecules completely in one or the other conformational state. The mathematical model on which the theory is based contains only one more adjustable parameter than the equilibrium model, but it adapts to the experimental results surprisingly well. The present kinetic results and equilibrium measurements on this system are described by the same values of those parameters which are common to both models. The found value of the rate constant of the propagation step, i.e. the cis ⇌ trans isomerization of a peptide bond at an existing I-II junction, agrees with the rate of isomerization in N,N-dimethylacetamide reported in the literature. The rate of nucleation is up to 105 times smaller than the rate of propagation.
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  • 121
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    Biopolymers 10 (1971), S. 739-751 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of glycosaminoglycans and ganglioside in distilled water are described, showing two bands in the region of amide and carboxyl transitions. The first, negative hand is common to all polymers and the amino sugar derivatives. The characteristics of the second band depend upon polymer structure. Those containing 4-1-linked amino sugars show a second, positive, resolved band about 190 mμ, while those with 3-1-linked amino sugars show a second, negative band less resolved from the first usually ≤185mμ, but clearly centered at 188mμ for dermatan sulfate. Ultraviolet optical absorption from 300 to ∼183 mμ showed inflection regions around 190 mμ for most compounds.
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  • 122
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of γ-benzyl glutamate NCAs has been investigated. The results indicate that a coil-to-helix transformation is not responsible for the kinetic data. The results were rationalized by assuming formation of polymer aggregates coupled with the stereoselective adsorption of monomer onto growing polymer prior to reaction. From kinetic data a ratio of equilibrium constants for adsorption was determined. Independent data confirmed the assumption that adsorption of monomer onto polymer occurred. Equilibrium constants were evaluated, and their ratio was found to be comparable with that obtained from the kinetic data.
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  • 123
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    Biopolymers 10 (1971), S. 849-863 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A preliminary neutron-scattering study of wet-spun oriented NaDNA samples with various contents of H2O or D2O has been performed to obtain information about the hydration of NaDNA. The preferred orientation was in the direction of the crystallographic c axis. Perpendicular to this direction the samples could be regarded as poly-crystalline. It has been found that the preferred crystallite orientation was also reflected in the water structure. This fact, taken together with the small energy widths of the measured near-elastic peaks indicates that water molecules in the sample are relatively strongly bound to the DNA helix either directly or via other water molecules. Angular distribution measurements of elastically scattered neutrons were performed with the momentum transfer vector directed along and perpendicular to the DNA helix axis. Different Debye-Waller factors were obtained, indicating different water dynamics in the two directions. Comparison between the H2O and D2O measurements suggests that the difference is caused by motions of rotational nature. The shape of the frequency distribution function for the H2O molecules in the NaDNA sample was somewhat similar to that which has been measured in ice.
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  • 124
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    Biopolymers 10 (1971), S. 865-882 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The linear dichroism induced in a solution of electrically anisotropic molecules by a pulsed electric field has been studied. Equations have been obtained which express the dichroism as a function of dipole moment, excess polarizability, field strength, and the angle α between the dipole moment and the transition moment for the absorption band. These expressions have been related to the experimentally observed difference signal in such a way that when the dichroism is measured as a function of field strength the permanent moment, excess polarizability and angle a can be determined.Experiments have been carried out on tobacco mosaic virus (TMV), which is similar in its properties to the theoretical model. The polarizability anisotropy and rotary diffusion constant for the monomer and dimer of TMV have been obtained from these experiments. In addition to the molecular parameters mentioned above, the saturated electric dichroism of the virus was measured as a function of wave length and the presence of an n-π* transition in the tryptophan spectrum was indicated.Further experiments measuring dichroism as a function of pH demonstrated the general denaturation of the virus at high pH (10-11) but also the existence of a stable fraction which is not fragmented even at the high pH involved.
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  • 125
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    Biopolymers 10 (1971), S. 2459-2490 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding of Mg ++ to polyadenylate (poly A), Polyuridylate(poly U), and their complexes, poly (A + U) and poly (A + 2U), was studied by means of a technique in which the dye eriochrome black T is used to measure the concentration of free Mg-. The apparent binding constant KX = [MgN]/[Mg++][N], N = site for Mg++ binding (the phosphate group of the nucleotide), was found to decrease rapidly as the extent of binding increased and, at low extents of binding, as the concentration of Na- increased in poly A, poly (A + U), and poly (A + 2U), and somewhat less so in poly U. Kx is generally in the range 104 〉 KX 〉 102. The cause of these dependences is apparently, primarily, the displacement of Na+ by Mg++ in poly U and poly (A + U) on the basis of the similarity of extents of displacement measured in this work and those measured potentiometrically. \documentclass{article}\pagestyle{empty}\begin{document}$$ \Delta H'{\rm v}.{\rm H}. = - R(\partial {\rm }\ln Kx/\partial 1/T)_\theta,\theta = \frac{{{\rm Mg}N}}{{N_t }} $$\end{document} was calculated and was found to approach zero as the concentration of Na+ increased. In poly U, poly (A + U), and poly (A + 2U) at low ΔH′ v.H. 〉 0, about + 2 kcal/“mole.” In poly A, also at low salt, ΔH′ v.H. ≈ -4 kcal/“mol” for the initial binding of Mg++, and increases to +2 kcal/“mol” at saturation. This enthalpic variation probably accounts for the anticooperativity in the binding of Mg++ not ascribable to the displacement of Na++.
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  • 126
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    Biopolymers 10 (1971), S. 2581-2590 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-resolution nuclear magnetic resonance spectra at 100 MHz have been obtained on poly-N-methyl-L-alanine in the chloroform-trifluoroacetic acid system under various conditions of solvent composition. Different spectra are observed for the CH3-Cα, Cα-H, and N-CH3 protons. On the basis of conformational analysis an interpretation of the NMR results was attempted.
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  • 127
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    Biopolymers 10 (1971), S. 2607-2614 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of optical rotatory dispersion and circular dichroism of RNA is described which leads to an estimate of the degree of base pairing. By the use of new standards for the double-helical parts of the molecule, based on data for two-stranded viral RNA species, a good fit between calculated and observed curves can be achieved. Where data are available the results of analyses of optical rotatory dispersion and circular dichroism in general show satisfactory consistency.
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  • 128
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    Biopolymers 10 (1971), S. 2625-2628 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 129
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    Biopolymers 10 (1971), S. 2645-2648 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Chemie in unserer Zeit 5 (1971), S. 19-23 
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    Chemie in unserer Zeit 5 (1971), S. 192-194 
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    Berichte der deutschen chemischen Gesellschaft 104 (1971) 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 21-30 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diastereomers of Nonactin Acid and Epimers of 2-Desmethylnonactin AcidNonactin acid 8a was prepared in only four reaction steps starting from the furan 3a. - In an attempt to prepare nonactin acid by intramolecular cyclisation of 13, the tetrahydropyran 15 was obtained in addition to the desired tetrahydrofuran 14. Treatment of 14 + 15 with sodium cyanide under the conditions of the Kolbe reaction led to the formation of the isomeric acids 16 + 17.
    Notes: Ausgehend von dem Furan 3a gelangt man in vier Reaktionsschritten zur Nonactinsäure 8a, einem 2.5-disubstituierten Tetrahydrofuran. - Beim Versuch der Darstellung von Nonactinsäure durch intramolekulare Cyclisierung von 13 entstand neben dem gewünschten Tetrahydrofuran 14 durch Ringerweiterung auch das Tetrahydropyran 15. Die Umwandlung von 14 + 15 mit Natriumcyanid nach Kolbe führte zu den stellungsisomeren Säuren 16 + 17.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 40-49 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Solvent Induced Shifts (ASIS) in the N.M.R. Spectra of tert-Butyl-, tert-Butoxy-and Nitro(tert-butyl)benzene DerivativesThe n.m.r. spectra of aromatic tert-butyl and tert-butoxy groups which are not separated in CCl4 may always be resolved in benzene and pyridine solution. In some cases (e. g. 15) assignements for these signals are obtained empirically from their solvent shifts. The signals of the aromatic protons in 2.6- and 3.4-dinitro-1-tert-butylbenzene show remarkable solvent effects (CCl4→C6D6) which cannot be explained by the 1:1 complex models. The shifts induced by aromatic solvents must originate rather from the time average over all orientations of the anisotropic molecules in the nearest solvent schell. The interpretation of such solvent shifts should be based on values derived from an absolute standard.
    Notes: In CCl4 nicht getrennte NMR-Signale für aromatisch gebundene tert.-Butyl- und tert.-Butyloxygruppen werden in Benzol und Pyridin stets aufgelöst und können in bestimmten Fällen (z. B. 15) an Hand der Lösungsmittelabhängigkeit empirisch zugeordnet werden. Die Ringprotonensignale bei 2.6- und 3.4-Dinitro-1-tert.-butyl-benzol zeigen beim Lösungsmittelwechsel CCl4→C6D6 sehr unterschiedliche und z. T. sehr starke Verschiebungen, die nicht mit dem Modell spezifischer 1:1-Komplexe erklärt werden können. Die Wirkung des aromatischen Lösungsmittels muß vielmehr durch das Zeitmittel über alle Orientierungen aller anisotroper Moleküle in der engsten Solvathülle zustandekommen. Auf die Verwendung eines absoluten Standards bei der Deutung von Lösungsmitteleffekten in der NMR-Spektroskopie wird hingewiesen.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 473-478 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 7-β-Neohesperidosyl-4′-(β-D-glucopyranosyl)naringenin, a Flavanone Triglycoside from Citrus FruitsThe glycoside 7-β-neohesperidosyl-4′-(β-D-glucopyranosyl)naringenin (3), isolated from the segments of Citrus paradisi Macf, by Mizelle et al., was synthesized by condensation of phloracetophenone 4-β-neohesperidoside (1) with 4-hydroxybenzaldehyde 4-β-D-glucopyranoside (2) and by cyclisation of the resulting chalkone glykoside. Dehydrogenation of the flavanone triglykoside undecaacetate and subsequent saponification leads to the formation of 7-β-neohesperidosyl-4′-(β-D-glucopyranosyl)apigenin (7), the first synthetic apigenin triglycoside.
    Notes: Das von Mizelle und Mitarbb. aus Citrus paradisi Macf. isolierte 7-β-Neohesperidosyl-4′-β-D-glucopyranosyl-naringenin (3) wurde durch Kondensation von Phloracetophenon-4-β-neohesperidosid (1) mit 4-Hydroxy-benzaldehyd-4-β-D-glucopyranosid (2) und Cyclisierung des entstandenen Chalkonglykosids synthetisiert. Durch Dehydrierung des Flavanontriglykosid-undecaacetats (3a) wurde nach Verseifen das 7-β-Neohesperidosyl-4′-β-D-glucopyranosyl-apigenin (7) als erstes synthetisches Apigenintriglykosid dargestellt.
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    Description / Table of Contents: Theoretical and Spectroscopic Investigations of Indigo Dyes, XI. Compounds with the Basic Chromophore of Thioindigo: Preparation and Properties of 3.4-Bis(alkylthio)hex-3-ene-2.5-dionesThe nucleophilic exchange of halogen in trans-3.4-dibromo- and -3.4-dichlorohex-3-ene-2.5-dione (4 and 5) with alkanethiols is studied. With bromine as leaving group substitution and reductive debromination leads to the formation of trans-3-methylthiohex-3-ene-2.5-dione (7a). With chlorine the expected trans-3.4-bis(alkylthio)hex-3-ene-2.5-diones (6a-c) are formed. These have the same structure and geometry as the basic chromophore of thioindigo, but they do not show the corresponding typical chemical and spectroscopic properties. They rather behave spectroscopically like β-alkylthio-α,β-unsaturated ketones. Conformation and spectroscopic properties of 6a-e are discussed with respect to the sterical requirements of the different groups at the sulfur atoms.
    Notes: Der Austausch der beiden Halogenatome von trans-3.4-Dibrom- und -3.4-Dichlor-hexen-(3)-dion-(2.5) (4 und 5) gegen Alkylmercaptane wird untersucht. Mit Brom als Abgangsgruppe erfolgt neben einfachem Austausch quantitativ eine reduktive Entbromierung zu trans-3-Methylmercapto-hexen-(3)-dion-(2.5) (7a), während mit Chlor als Abgangsgruppe zweifacher Austausch zu trans-3.4-Bis-alkylmercapto-hexen-(3)-dionen-(2.5) (6a-e) stattfindet. Diese zeigen nicht die spektroskopischen und chemischen Eigenschaften, die man für dieses - in der Verknüpfung ihrer funktionellen Gruppen dem Thioindigogrundchromophor entsprechende - System erwartet, sondern sie verhalten sich wie einfache β-alkylmercapto-α,β-ungesättigte Ketone. Die Abhängigkeit der Konformation und der spektroskopischen Eigenschaften von der Größe der Alkylreste am Schwefel wird diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 549-557 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, LIV. Chemical Properties of Tris(2.2-dimethylhydrazino)boraneIn contrast to the ready cleavage of BN-bonds in tris(dialkylamino)boranes by BCl3, (BH3)2, HCl or CH3J the prefered reactions of these acids with tris(2.2-dimethylhydrazino)borane (1) are additions. Due to the greater basicity of the dimethylamino group as compared to the NH moiety, additions occur at the group (CH3)2N before the group NH is attacked. Solvolysis of B[NH—N(CH3)2]3 (1) by H2O or C2H5OH yields (CH3)2 N—NH2 and B(OH)3 or B(OC2H5)3, respectively, but no mixed compounds XnB[NH—N(CH3)2]3 n are formed in these reactions or by ligand exchange with B(OCH3)3 or B[N(CH3)2]3. 1 is stable up to 280° at higher temperature condensation with formation of N.N-dimethylhydrazine occurs.
    Notes: Während die Verbindungen BCl3, (BH3)2, HCl und CH3J die B N-Bindungen von Tris(dialkylamino)-boranen spalten, lagern sie sich an Tris(2.2-dimethyl-hydrazino)-boran (1) an. Dabei erfolgt zunächst Addition an die stärker basische Dimethylaminogruppe, danach reagiert auch die schwächer basische NH-Gruppe. Solvolysen von 1 mit H2O und C2H5OH oder Komproportionierungen mit B(OCH3)3 oder B[N(CH3)2]3 führen nicht zu gemischten Verbindungen XnB[NH—N(CH3)2]3 n(X—OH, OR, N(CH3)2). Im Vergleich zu Tris(alkylamino)-boranen ist 1 thermisch sehr stabil. Erst oberhalb 280° spaltet sich N,N-Dimethylhydrazin ab.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 605-638 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: o- and p-(Dicyanomethylene)quinocyclopropenes. Synthesis, Mechanisms of Formation and Propertieso- and p-quinocyclopropenes of the benzene, naphthalene, anthracene, phenanthrene, and fluorene series (9, 12-15, 29, 30b, 37, 38) are prepared a) by thermolysis of 1:1 adducts of 3-ethoxy-1.2-diaryl-cyclopropenylium cations 6 and arylmalodinitrile anions, b) by reaction of diarylcyclopropenones with arylmalodinitriles in acetic anhydride. The reaction mechanisms suggested by isolation of intermediates are discussed. - Polarography of the quinocyclopropenes shows reversible formation of a radical cation in a one-electron step. This is in agreement with calculations according to the simple HMO model, which give satisfactory correlations with polarography, u. v. and i. r. spectroscopical data.
    Notes: o- und p-Chinocyclopropene der Benzol-, Naphthalin-, Anthracen-, Phenanthren- und Fluorenreihe (9, 12-15, 29, 30b, 37, 38) werden dargestellt a) durch Thermolyse von 1:1-Addukten aus 3-Äthoxy-1.2-diaryl-cyclopropenylium-Kationen 6 und Arylmalodinitril-Anionen, b) durch Reaktion von Diarylcyclopropenonen und Arylmalodinitrilen in Acetanhydrid. Die sich aus der Isolierung von Zwischenprodukten ergebenden Reaktionsmechanismen werden diskutiert. - Durch polarographische Untersuchungen wird festgestellt, daß die Chinocyclopropene reversibel im Einelektronenschritt in ein Radikal-Kation übergehen. Dies wird durch Rechnungen nach dem einfachen HMO-Modell bestätigt, die befriedigende Korrelationen mit den polarographischen sowie UV- und IR-spektroskopischen Daten ergeben.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 665-667 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 668-670 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 71-74 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Bromination of Hydrocarbons in Liquid BromineThe bromination of aliphatic hydrocarbons in liquid bromine in the presence of catalytic amounts of hydrobromic acid is described. Hydrocarbons with neighbouring tertiary carbon atoms and tetraalkylated ethylenes give definite bromination products. From the corresponding hydrocarbons were obtained 1.4-Dibromo-2.3-bis(bromomethyl)but-2-ene (1), 1.4.5-Tribromo-2.3-bis(bromomethyl)pent-2-ene (2), 1.4.5-Tribromo-2.3-bis(bromomethyl)-hex-2-ene (3), 1.4.5-Tribromo-2-bromomethyl-3-(α.β-dibromoethyl)pent-2-ene (4), and 1.4.5.8-Tetrabromo-Δ4a(8a)-octalin (5).
    Notes: Bei der Bromierung in flüssigem Brom in Gegenwart katalytischer Mengen Bromwasserstoffsäure bilden aliphatische Kohlenwasserstoffe mit benachbarten tertiären Kohlenstoffatomen und tetraalkylierte Äthylene definierte Bromierungsprodukte. Im einzelnen werden 1.4-Dibrom-2.3-bis-brommethyl-buten-(2) (1), 1.4.5-Tribrom-2.3-bis-brommethyl-penten-(2) (2), 1.4.5-Tribrom-2.3-bis-brommethyl-hexen-(2) (3), 1.4.5-Tribrom-2-brommethyl-3-[α.β-dibromäthyl]-penten-(2) (4) und 1.4.5.8-Tetrabrom-Δ4a(8a)-octalin (5) aus den entsprechenden Kohlenwasserstoffen erhalten.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 110-130 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Four-Centre π-Systems, III. Colour, Solvatochromy and Reduction Potentials of (1.4-Diazabutadiene)molybdenum TetracarbonylsMolybdenum tetracarbonyl complexes of the =N=C=C=N-system (1,4-diazabutadiene=DAB) show an intense, low energy electronic transition, which is antiparallel to the ground state dipole moment; its solvent dependance is measured for 33 mostly new compounds and shows directly the amount of metal-ligand interaction, and thus of π-backbonding. The π-delocalisation of metal-D-electrons strongly depends on the substituents of the DAB-system, but the complex ground state has still molybdenum in the valence state 0. The competing mesomeric, inductiv and steric effects of the DAB ligands can be separated, too, by polarographic reduction potentials of complexes and ligands. The results can be understood in terms of simple perturbation theory.
    Notes: Molybdäncarbonyl-Komplexe des =N=C=C=N-Systems (1.4-Diaza-butadien=DAB) zeigen eine antiparallel zum Grundzustandsdipolmoment gerichtete intensive farbgebende Elektronenanregung, deren an dreiunddreißig meist neuen Verbindungen untersuchte Solvatochromie direkte Aussagen über die Größe der Metall-Ligand-Termwechselwirkung und damit über die π-Rück bindung gestattet. Die Delokalisierung der Metall-D-Elektronen ist abhängig von den Substituenten des DAB-Systems, der Komplexgrundzustand enthält aber formal 0-wertiges Molybdän. Die konkurrierenden induktiven, mesomeren und sterischen Effekte der DAB-Liganden sind in den polarographischen Reduktionspotentialen der Komplexe und Liganden selbst ebenfalls genau abgrenzbar, bestätigen die Solvatochromie-untersuchungen und lassen sich im Rahmen einfacher Störungstheorie widerspruchsfrei deuten.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 138-144 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reductive Silylation of NaphthaleneThe reaction of naphthalene with trimethylchlorosilane and sodium has been found to afford 1.4-bis(trimethylsilyl)-1.4-dihydro- and 1.2-bis(trimethylsilyl)-1.2-dihydronaphthalene (1, 2), whereas potassium reacts to give mainly 1.2.3.7-tetrakis(trimethylsilyl)-1.2.3.4-tetrahydro-naphthalene (3) besides 1.2.4-tris(trimethylsilyl)-1.4-dihydro-(4) and 1.2.4-tris(trimethylsilyl)-1.2-dihydronaphthalene (5). The configuration has been determined by n.m.r. spectroscopy.
    Notes: Bei der reduktiven Silylierung von Naphthalin mit Natrium und Trimethylchlorsilan werden vorwiegend nur 1.4-Bis-trimethylsilyl-1.4-dihydro- und 1.2-Bis-trimethylsilyl-1.2-dihydronaphthalin (1, 2) gebildet. Ersetzt man jedoch das Natrium durch Kalium, so erhält man 1.2.4-Tris-trimethylsilyl-1.4-dihydro- (4) sowie 1.2.4-Tris-trimethylsilyl-1.2-dihydro-naphthalin (5) und vor allem 1.2.3.7-Tetrakis-trimethylsilyl-1.2.3.4-tetrahydro-naphthalin (3). - Die Aufklärung der Konfiguration erfolgte NMR-spektroskopisch.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 168-172 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of 4-Chloro- and 4-Bromo-2H-chromenes and of 3-Bromo-2H-chromenesDehydrobromination of trans-3,4-dihalochromans yields the 4-halo-2H-chromenes 1-4. Dehydration of cis-3-bromo-4-hydroxychromans leads to the 3-bromo-2H-chromenes 5 and 6.
    Notes: Durch Abspaltung von Bromwasserstoff entstehen aus den trans-3.4-Dihalogen-chromanen die entsprechenden 4-Halogen-2H-chromene 1-4. Die 3-Brom-2H-chromene 5 und 6 erhält man durch Dehydratisierung der cis-3-Brom-4-hydroxy-chromane.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 210-219 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinylogous Acyl Compounds, IX. Hydrolysis of Vinylogous Carbonamidium SaltsThe hydrolysis of vinylogous carbonamidium salts 10 in aqueous sodium hydrogen carbonate solution does not lead - as hitherto supposed - to meso-(2-acylvinyl)acylacetaldehydes 8, but to bis(2-acylvinyl)ethers 11. The structure of these compounds results from n. m. r. and i. r. spectra and is confirmed by independent synthesis.
    Notes: Die Hydrolyse vinyloger Carbonamidiumsalze 10 in wäßriger Natriumhydrogencarbonat-Lösung führt nicht - wie bisher angenommen - zu meso-[2-Acyl-vinyl]-acylacetaldehyden 8, sondern zu Bis-[2-acyl-vinyl]-äthern 11. Die Strukturzuordnung dieser Verbindungen gründet sich auf NMR- und IR-spektroskopische Befunde sowie auf eine unabhängige synthese.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 160-167 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1.2.3-Tricarbonyl Compounds, V. Hydrate-forming 1.2.3-Tricarbonyl Compounds as Dienophiles in Diels-Alder ReactionsThe 1.2.3-tricarbonyl compounds 5-8 react as dienophiles and add isoprene or 2.3-dimethylbuta-1.3-diene to yield the spiro-dihydropyranes 9-16. I.r., mass, and n.m.r. spectra are discussed.
    Notes: Cyclische 1.2.3-Tricarbonylverbindungen (vgl. 5-8) reagieren als Dienophile mit Isopren und 2.3-Dimethyl-butadien-(1.3) unter Bildung der Spiro-dihydropyrane 9-16. Die IR- und Massenspektren der Reaktionsprodukte sowie die NMR-Spektren von 9 und 10 werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 205-209 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbiological 11β-Hydroxylation of 3β-Hydroxy-5α.6α-epoxysteroidsSome 3β-Hydroxy-5α,6α-epoxysteroids are hydroxylated specifically in 11β-position without formation of by-products by the fungus Curvularia lunata.
    Notes: Eine Reihe von 3β-Hydroxy-5α.6α-epoxy-steroiden wird mit dem Pilz Curvularia lunata ohne Bildung von Nebenprodukten spezifisch in 11β-Stellung hydroxyliert.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 248-258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isoquinolines, II. 3.3-Dialkyl-3.4-dihydroisoquinolines from Alkyl-aryl-cyclopropanesUnder the conditions of the Graf-Ritter reaction alkyl-aryl-cyclopropanes 8 react with nitriles 2 via dialkyl-benzyl-carbonium ions 1 to give 3.3-dialkyl-3.4-dihydroisoquinolines 3. The effect of the substituents R1, R2, and R3 in 8 on the reaction is discussed.
    Notes: Alkyl-aryl-cyclopropane 8 reagieren unter den Bedingungen der Graf-Ritter-Reaktion über Dialkyl-benzyl-carboniumionen 1 mit Nitrilen 2 zu 3.3-dialkylsubstituierten 3.4-Dihydroisochinolinen 3. Der Einfluß der Substituenten R1, R2 und R3 in 8 auf den Reaktionsverlauf wird besprochen.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 270-278 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Aromatic Erythrina-Alkaloids, XVIII. Concerning the Existence of trans-ErythrinanesWolff-Kishner reduction of the 6α-bromo-ketolactam 2 affords, among other products, the 6β-hydroxyerythrinane-8-one 8. This is the first compound of the trans-erythrinane series.
    Notes: Bei der Wolff-Kishner-Reduktion des 6α-Brom-ketolactams 2 entsteht neben anderen Produkten auch das 6β-Hydroxy-erythrinanon-(8) 8, der erste Vertreter der trans-Erythrinan-Reihe.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 320-332 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ionization of Organomagnesium Compounds, IV. Formation of Carbanions from Organomagnesium Compounds by Means of Hexamethyl-phosphortriamideStepwise addition of hexamethylphosphortriamide (HMPT) to the solutions of benzyl-like organomagnesium compounds in diethylether results in drastic changes which can be observed spectroscopically. First, the absorption maxima are shifted to longer wave lengths in an apparently continuous manner, until two equivalents of the strongly donating cosolvent have been added. Further addition of HMPT leads to ionization of the C—Mg-bonds. This can be seen from the development of new bands characteristic of the carbanions, as represented by the alkali metal derivatives.
    Notes: Der Zusatz von Hexamethylphosphorsäuretriamid (HMPT) zu den ätherischen Lösungen von benzylartigen Organomagnesium-Verbindungen führt zu drastischen, spektral beobachtbaren Veränderungen. Zunächst tritt eine scheinbar kontinuierliche Verschiebung der Absorptionsmaxima nach längeren Wellen ein, bis zwei Äquivalente des starken Donor-Solvens zugesetzt sind. Weitere Zugabe von HMPT führt zur Ionisation der C—Mg-Bindungen und Freisetzung der betreffenden Carbanionen, die sich durch das Aufkommen der (von den Alkalimetall-Verbindungen bekannten) Carbanion-Banden zu erkennen gibt.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 343-343 
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    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 350-351 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Topics: Chemistry and Pharmacology
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 391-401 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of Small Rings, 23. Carbenacyclopentadienes and Alkynes. - Photochemical Synthesis of Benzindenes and SpirocyclopropenesPhotolysis of phenyl-substituted diazocyclopentadienes 3 in alkynes leads via the intermediate carbenacyclopentadienes to the formation of 1H-benz[e]indenes 5. 5c was degraded to the known compound 3-phenyl-2.3-dihydro-1H-benz[e]indene (8). - On irradiation 3a, f in dimethyl acetylenedicarboxylate yield the spiro[2.4]heptatrienes 9 instead of 5. 9a was rearranged by further irradiation to the benz[e]indene 5f. - The mechanism of the benzindene formation is discussed.
    Notes: Die Photolyse phenyl-substituierter Diazo-cyclopentadiene 3 in Alkinen führt über die Carbena-cyclopentadiene zu 1H-Benz[e]indenen 5. 5c wurde zum bekannten 3-Phenyl-2.3-dihydro-1H-benz[e]inden (8) abgebaut. - Die Bestrahlung von 3a, f in Acetylendicarbonester ergab jedoch nicht 5, sondern die Spiro[2.4]heptatriene 9. 9a wird durch weitere Belichtung in das Benz[e]inden 5f umgelagert. - Der Mechanismus der Benzinden-Bildung wird diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 421-428 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Michael Additions with Ethyl β-Arylacrylates: The Synthesis of 3-Aryl-2.2-bis(ethoxycarbonyl)-5-pyrrolidonesThe Michael reaction of ethyl β-arylacrylates with diethyl acetaminomalonate followed by cyclisation directly yielded the 3-aryl-2.2-bis(ethoxycarbonyl)-5-pyrrolidones (4).
    Notes: β-Aryl-acrylsäure-äthylester werden mit Acetamino-malonsäure-diäthylester nach Michael unter nachfolgender Cyclisierung direkt zu 3-Aryl-2.2-bis-äthoxycarbonyl-pyrrolidonen-(5) (4) umgesetzt.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 461-472 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Chalcogen Compounds Diphenyldithiophosphinato Complexes of Vanadium(III), Vanadium(IV) and Molybdenum(VI)The preparation and properties of the compounds [(C6H5)2PS2]2MoO2 (3), [(C6H5)2PS2]2-VO (4) and [(C6H5)2PS2]3 V (5) are described. Their vibrational and electronic spectra are reported. The parameters 10 Dq = 13 200/cm and B = 395/cm were calculated from the electronic spectrum of the vanadium(III) compound.
    Notes: Die Darstellung und Eigenschaften der Verbindungen [(C6H5)2PS2]2MoO2 (3), [(C6H5)2PS2]2-VO (4) und [(C6H5)2PS2]3 V (5) werden beschrieben. Die Schwingungs- und Elektronenspektren werden mitgeteilt und letztere mit der Kristallfeldtheorie interpretiert. Für die Vanadin(III)-Verbindung lassen sich aus den Übergängen ν1(3T1g→3T2g) und ν2(3T1g(F) → 3T1g(P)) die Werte für 10 Dq 13200/cm und B 395/cm berechnen.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 513-518 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reaction of Boron-Nitrogen Compounds with Excited Carbon Atoms Generated in an ArcThe interaction of carbon vapor from a carbon are with dimethylaminoborane, (CH3)2N—BH2 (1), yields as the main reaction product (dimethylamino)methylborane, (CH3)2 N—BH—CH3 (3), which combines with the starting material to form the four-membered ring compound 5. Other compounds formed in this reaction are (dimethylamino)dimethylborane, (CH3)2N—B(CH3)2 (2), and dimethylaminborane, (CH3)2NH—BH3, as well as the previously unknown compound (CH3)2N—BH—O—BH—N(CH3)2 (6), which could be isolated.
    Notes: Die Reaktion von im Lichtbogen erzeugten Kohlenstoffatomen mit Dimethylaminoboran, (CH3)2N—BH2 (1), ergibt als Hauptreaktionsprodukt das Dimethylamino-methylboran, (CH3)2N—BH—CH3 (3), das sich mit dem Ausgangsmaterial zur Vierringverbindung 5 umsetzt. Weiterhin findet man Dimethylamino-dimethylboran, (CH3)2N—B(CH3)2 (2) und Dimethylamin-boran, (CH3)2NH—BH3. Schließlich kann die bisher noch nicht bekannte Verbindung (CH3)2N—BH—O—BH—N(CH3)2 (6) isoliert werden.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 528-532 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Simple Pathway to Azide-Bridged Palladium and Platinum(II) ComplexesSalts of azide-bridged dimeric cations are prepared in quantitative yields by reaction of the monomeric diazido complexes (Ph3P)2 M(N3)2 with nitrosyl- or triethyloxonium salts, and diethyl sulfate, respectively.
    Notes: Salze der azidverbrückten dimeren Kationen entstehen in praktisch quantitativer Ausbeute durch Umsetzung der monomeren Diazidokomplexe (Ph3P)2 M(N3)2 mit Nitrosyl- oder Triäthyloxonium-Salzen bzw. mit Diäthylsulfat.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 558-576 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, LV. Intramolecular Hydrogen Bonding in (2.2-Dimethylhydrazino)boranesN. m. r. spectroscopic investigations on (2.2-dimethylhydrazino)boranes demonstrate the presence of intramolecular hydrogen bonds in these compounds, and this is further proved by comparison with isopropylaminoboranes. The planar configuration of B[NH—N(CH3)2]3 and B2[NH—N(CH3)2]4 is determined by this bonding. The N—H … N bond energy has been estimated as ∼2.5 kcal/mole from the temperature dependence of the n. m. r. spectra. Intermolecular association is indicated in the compounds R2B—NH—N(CH3)2. - The basicity towards the acid CDCl3 decreases in the isopropylaminoborane series for (2.2-dimethylhydrazino)boranes the series has been found confirming the effects of intramolecular hydrogen bonding.
    Notes: Kernresonanzspektroskopische Untersuchungen an (2.2-Dimethyl-hydrazino)-boranen belegen durch Vergleich mit Isopropylamino-boranen intramolekulare Wasserstoffbrückenbindungen. Diese sind insbesondere für B[NH—N(CH3)2]3 und B2[NH—N(CH3)2]4 konfigurationsbestimmend. Ihre Bindungsenergie beträgt ∼2.5 kcal/Mol. In R2B—NH—N(CH3)2 erfolgt Assoziation über intermolekulare N—H … N-Bindungen, die in Lösung leicht aufbrechen. - Basizitätsbestimmungen mit der Referenzsäure CDCl3 ergeben die Reihe für die Isopropylamino-borane, jedoch für die (2.2-Dimethyl-hydrazino)-borane in Übereinstimmung mit den durch intramolekulare Wasserstoffbrückenbindungen bewirkten Effekten.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 4-10 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of Thioamides and their Derivatives, XI. N.M.R-Spectroscopic Studies and the Mechanism of Isomerization of Thioamide anionsIn the n. m. r. spectra of thioformamide anions 2 a larger trans long-range coupling constant is observed than in the spectra of the corresponding thioformamides 1. In spite of this spectral evidence indicating that 2 has the stronger partial double bond character, 2 isomerizes faster than 1. This suggests that isomerization proceeds via an inversion mechanism, an assumption which is verified by the steric effects of o-substituents in thioformanilide anions 4. On the other hand, in the case of thioformanilides 3 a rotation mechanism is observed.
    Notes: In den NMR-Spektren von Thioformamid-Anionen 2 wird eine größere trans-Fernkopplungskonstante als in den entsprechenden Thioformamiden 1 gefunden. Trotz des daraus zu folgernden größeren Doppelbindungscharakters wird bei 2 eine schnellere Isomerisierung als bei 1 beobachtet. Der dadurch nahegelegte Inversionsmechanismus wird durch den sterischen Einfluß von o-Substituenten in den Thioformanilid-Anionen 4 belegt, während für die Thioformanilide 3 ein Rotationsmechanismus gefunden wird.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 50-58 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions with Carbodiimides, 1. Influences of Substituents in the Cycloaddition of Ketenes to CarbodiimidesCarbodiimides and ketenes yield 4-imino-2-azetidinones (1-14) in a cycloaddition reaction. Aliphatic carbodiimides show higher reactivity than aromatic carbodiimides. In mixed aliphatic-aromatic substituted carbodiimides, therefore, preferentially one of the C=N bonds undergoes reaction. The structures of the resulting compounds were confirmed by chemical transformations, i.r., and n.m.r. spectra.
    Notes: Carbodiimide gehen mit Ketenen Cycloadditionen zu 4-Imino-azetidinonen-(2) (1-14) ein. Aliphatisch substituierte Carbodiimide sind reaktiver als aromatisch substituierte. Bei aliphatisch-aromatisch substituierten Carbodiimiden gelingt es daher, bevorzugt eine der beiden C=N-Doppelbindungen zur Reaktion zu bringen. Die Konstitutionen der 4-Iminoazetidinone-(2) ergeben sich aus IR- und NMR-Spektren in Verbindung mit chemischen Umwandlungen.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 75-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Higher Ring Systems with the Structural Characteristics of the Diamond-type Lattice, 1. Enamine Formation and Ring Fusion in the Case of Bicyclo[3,3,1]nonane-3,7-dioneBicyclo[3.3.1]nonane-3.7-dione can be condensed with pyrrolidine to form 1.3-dipyrrolidino-2-oxaadamantane. From this system the mono- and bis-pyrrolidinoenamine of bicyclo[3.3.1]-nonane-3.7-dione (3,5) can be obtained. The reaction of the bis-enamine 3 with ethyl bromomethylacrylate leads to the pentacycle 4.
    Notes: Bicyclo[3.3.1]nonandion-(3.7) (1) kann mit Pyrrolidin zum 1.3-Dipyrrolidino-2-oxa-adamantan (2) kondensiert werden. Aus diesem System sind das Mono- und Bis-pyrrolidin-Enamin des Bicyclo[3.3.1]nonandions-(3.7) (3.5) erhältlich. Über das Bis-Enamin 3 kann mit α-Brom-methyl-acrylsäure-äthylester der Pentacyclus 4 auf gebaut werden.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 92-109 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Copper(I)-diazabutadiene Halides1,4-Diazabuta-1,3-dienes react with cuprous halides to form strongly coloured, monomeric 1:1 adducts 2-11, 16-20, 24, 25, containing copper with threefold coordination. This coordination number determines the spectroscopic behaviour. While diazabutadiene complexes of other metals in low oxidation states show a long-wavelength absorption with strong metal-to-ligand CT character, in the copper complexes 2-11, 16-20, 24, 25 the metal terms are about equally important in the ground and excited state without showing the typical solvatochromism and the extremely high intensity of the chromogenic transition.
    Notes: 1.4-Diaza-butadiene-(1.3) bilden mit Kupfer(I)-halogeniden stark farbige, monomere 1:1-Komplexe 2-11, 16-20, 24, 25 mit dreifach koordiniertem Kupfer. Diese Koordination bestimmt das elektronenspektroskopische Verhalten. Während in Diazabutadien-Komplexen anderer Metalle in niedrigen Oxydationsstufen die längstwellige Absorption sehr starken Metall-Ligand-charge-transfer-Charakter hat, fehlt hier bei etwa gleich starker Beteiligung von Metalltermen im Grundzustand und angeregten Zustand die typische Solvatochromie und die extrem hohe Intensität des farbgebenden Übergangs.
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 145-149 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and N.M.R. Spectra of Trimethyl(allylidene)- and -(benzylidene)phosphoraneThe title compounds (1 and 2) have been prepared in a pure state for the first time. Their 1H n. m. r. spectra could be completely analysed and the data obtained are taken as evidence for a delocalisation of the ylidic carbanionic charge into the π-system.
    Notes: Trimethyl-allyliden- und -benzyliden-phosphoran (1 und 2) wurden erstmals rein dargestellt. Die 1H-NMR-Spektren ließen sich vollständig analysieren und im Sinne einer Delokalisierung der negativen Ladung in das π-System deuten.
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  • 187
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Organophosphorus CH-acidic Compounds with Schiff Bases in the Presence of Acid and Alkaline Catalysts, V. Reaction of Esters of Propylbenzylphosphinic Acid in the Presence of Sodium AmideThe reaction of esters 1 of propylbenzylphosphinic acid with Schiff bases 2 in the presence of sodium amide has been studied. In ether at -33° esters of (2-arylamino-1,2-diarylethyl)-propylphosphinic acids (3 and 4) are obtained in 20-81% yields. In ether at 10° and in liquid ammonia small amounts of trans-olefins (5) are formed along with the adducts 3 and 4 (the yields of which decrease). The reactivity of 1 is compared with that of the esters of benzyl-phosphonic acid, and the mechanism of the reaction of 1 with 2 is discussed.
    Notes: Bei der Umsetzung der Propyl-benzyl-phosphinsäureester 1 mit Schiffschen Basen 2 in Gegenwart von Natriumamid entstehen in Äther bei -33° Ester der [2-Arylamino-1.2-diaryläthyl]-propyl-phosphinsäuren (3 und 4) in 20-81 proz. Ausbeute. In Äther bei 10°, in geringem Umfang auch in flüssigem Ammoniak, bilden sich neben den verringert auftretenden Addukten 3 und 4 auch noch trans-Olefine (5). Die Reaktionsfähigkeit von 1 im Vergleich zu den Benzylphosphonsäureestern sowie der Mechanismus ihrer Umsetzung mit 2 werden diskutiert.
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  • 188
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 220-227 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: cis- and trans-3.3′-Dimethoxy-5.5′-di-tert-butyldiphenoquinone-(4.4′)The two geometric isomers of 3.3′-dimethoxy-5.5′-di-tert-butyldiphenoquinone-(4.4′) (1) were isolated. The configurational assignment was made on the basis of n.m.r. spectra and the X-ray diffraction pattern from single crystals. The free enthalpy of activation for the cis/trans-isomerisation was determined. -p-Diphenoquinones with different substituents in both rings, which were needed as model compounds, could be prepared for the first time.
    Notes: Die beiden geometrischen Isomeren des 3.3′-Dimethoxy-5.5′-di-tert.-butyl-diphenochinons-(4.4′) (1) wurden isoliert. Die Konfigurationszuordnung gelang anhand der NMR-Spektren sowie von Einkristall-Röntgenaufnahmen. Die Freie Aktivierungsenthalpie der cis/trans-Isomerisierung wurde bestimmt. -p-Diphenochinone mit verschiedenen Substituenten in beiden Ringen, als Vergleichssubstanzen benötigt, konnten erstmals dargestellt werden.
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  • 189
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 290-300 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reductive Rearrangements of the Retrobenzilic Acid Type Induced by Lewis Acids, VI. Crossing ExperimentsBy a series of crossing experiments the reductive retrobenzilic acid rearrangements of 5,5-diaryldithiohydantoins (1) and 4,4-diaryl-2-imidazoline-5-thiones (3), induced by aluminium chloride and yielding the corresponding 4,5-diaryl-4-imidazoline-2-thiones (2) and 4,5-diarylimidazoles (4), respectively, were shown to proceed intramolecularly.
    Notes: Durch eine Serie von Kreuzungsversuchen wird der intramolekulare Verlauf der durch Aluminiumchlorid ausgelösten reduktiven Retrobenzilsäure-Umlagerung von 5.5-Diaryl-dithiohydantoinen (1) und 4.4-Diaryl-Δ2-imidazolin-thionen-(5) (3) zu 4.5-Diaryl-Δ4-imidazolin-thionen-(2) (2) bzw. 4.5-Diaryl-imidazolen (4) erwiesen.
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  • 190
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 348-349 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 191
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 353-359 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Are Absolute Asymmetric Photosyntheses Possible?The addition of carbenes, generated from diazoalkanes by circularly polarized light, to trimethylethylene (1) yielded optically inactive cyclopropanes. Attempts to obtain a chiral photochemical cyclodimerisation of cyclopent-1-en-3-one (4) or to reproduce two absolute asymmetric photosyntheses described earlier also failed. Thus such syntheses appear to be questionable.
    Notes: Mit zirkular polarisiertem Licht aus Diazoalkanen erzeugte Carbene lieferten bei der Reaktion mit Trimethyläthylen (1) optisch inaktive Cyclopropane. Ebenso negativ verliefen Versuche, eine chirale photochemische Cyclodimerisierung von Cyclopenten-(1)-on-(3) (4) zu erzielen oder zwei früher beschriebene absolute asymmetrische Photosynthesen zu reproduzieren. Die Möglichkeit derartiger Synthesen scheint damit in Frage gestellt.
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  • 192
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 360-364 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1:1-Complexes of Mercuric Halides with MethyldiphenylstibineThe complexes [HgX2·SbCH3(C6H5)2]2 mit X=Cl (5), Br (6), J (7) precipitated on combination of equimolar amounts of the components in methanol or acetone solution. Dimeric, halogen-bridged structures for these complexes have been derived from infrared spectra (300-33/cm). The ligand methyldiphenylstibine (4) has been obtained in 89% yield by reaction of dijodomethylstibine (3) with phenylmagnesium bromide.
    Notes: Die Komplexe [HgX2·SbCH3(C6H5)2]2 mit X=Cl (5), Br (6), J (7) fallen bei der Vereinigung äquimolarer Mengen der Komponenten in Methanol- oder Aceton-Lösung aus. Dimere, halogenverbrückte Strukturen dieser Komplexe werden aus Infrarotspektren (300-33/cm) abgeleitet. Der Ligand Methyldiphenylstibin (4) wird durch Reaktion von Dijodmethylstibin (3) mit Phenylmagnesiumbromid in 89 proz. Ausbeute erhalten.
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  • 193
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 407-411 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of α-Halocarbonyl Compounds with the Guanidine System. II. Reaction of ω-Bromoacetophenone with Anilinoguanidineω-Bromoacetophenone reacts with anilinoguanidine to give 2-amino-1-anilino-4-phenylimidazole (1a). On treatment with boiling hydrochloric acid 1a undergoes benzidine-like rearrangement yielding 2-amino-4(5)-phenyl-5(4)-[p-aminophenyl]-imidazole (6).
    Notes: ω-Brom-acetophenon reagiert mit Anilino-guanidin zu 2-Amino-1-anilino-4-phenyl-imidazol (1a), das durch siedende Salzsäure benzidinartig in 2-Amino-4(5)-phenyl-5(4)-[p-amino-phenyl]-imidazol (6) umgelagert wird.
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  • 194
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 429-439 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Stereoselective Synthesis of cis-3-Aryl-2-ethoxycarbonyl-5-pyrrolidonescis-3-Aryl-2-ethoxycarbonyl-5-pyrrolidones (6) are obtainable from 3-aryl-2,2-bis(ethoxy-carbonyl)-5-pyrrol idones(1) via their dicarboxy-derivatives (3) or their half-esters (5) by moderate stereoselective decarboxylation.
    Notes: Aus 3-Aryl-2.2-bis-äthoxycarbonyl-pyrrolidonen-(5) (1) lassen sich über die Dicarboxy-Verbindungen (3) oder über die Halbester (5) durch mäßig stereoselektive Decarboxylierung cis-3-Aryl-2-äthoxycarbonyl-pyrrolidone-(5) (6) gewinnen.
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  • 195
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 456-460 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Chemical Synthesis of 2.4-Dithiopyrimidine Nucleoside-5′-mono- and -polyphosphatesThe synthesis of 2-thiothymidine-5′-phosphate (3), 2.4-dithiothymidine-5′-triphosphate (8c), 2.4-dithiouridine-5′-diphosphate (7a), 2.4-dithioribothymidine-5′-diphosphate (7b), and 2.4-dithiouridine-5′-triphosphate (8a) is reported. The behaviour in paper chromatography and paper electrophoresis as well as the phosphate content have been used as criteria of the purity.
    Notes: 2-Thio-thymidin-5′-phosphat (3), 2.4-Dithio-thymidin-5′-triphosphat (8c), 2.4-Dithio-uridin-5′-diphosphat (7a), 2.4-Dithio-ribothymidin-5′-diphosphat (7b) und 2.4-Dithio-uridin-5′-triphosphat (8a) wurden synthetisiert. Als Reinheitskriterien dienen das Verhalten in Papierchromatographie sowie Papierelektrophorese und der Phosphatgehalt.
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  • 196
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 519-523 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: E.S.R. Investigation of the Dinaphtho[2.3-c:2′.3′-h]phenothiazinyl Radical8H-Dinaphtho[2.3-c : 2′.3′-h]phenothiazine (1), obtained by reaction of di-2-anthrylamine with sulfur, yields the stable free radical 4 by dehydrogenation. For the solid state a free radical content of 85% has been determined by e. s. r. Solutions of 4 gave a complex e. s. r. spectrum which is discussed in connection with Hückel calculations.
    Notes: Das aus 2.2′-Dianthrylamin durch Umsetzung mit Schwefel zugängliche 8H-Dinaphtho-[2.3-c: 2′.3′-h]phenothiazin (1) liefert bei der Dehydrierung das stabile freie Radikal 4. Der Radikalgehalt beträgt im Kristall nach ESR-Messungen 85%. Lösungen von 4 liefern ein linienreiches ESR-Spektrum, das im Zusammenhang mit Hückel-Rechnungen diskutiert wird.
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  • 197
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 544-548 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: SO3-Insertion into Organopentacarbonylrhenium(I) CompoundsThe hitherto unknown sulfonato complexes CH3SO3ReI(CO)5 (4), C6H5SO3ReI(CO)5 (5), and p-CH3—C6H4SO3ReI (CO)5 (6) are obtained according to equation (1) by insertion of SO3 into the metal-carbon bond of CH3Re(CO)5 (1), C6H5Re(CO)5 (2), and p-CH3—C6H4Re(CO)5 (3). The composition and the structure of these compounds result from 1H n. m. r., mass, and i. r. spectroscopic investigations.
    Notes: Durch Einschiebung von SO3 in die Metall-Kohlenstoff-Bindung von CH3Re(CO)5 (1), C6H5Re(CO)5 (2) und p-CH3—C6H4Re(CO)5 (3) gelingt gemäß Gl. (1) die Darstellung der noch unbekannten Sulfonato-Komplexe CH3SO3ReI(CO)5 (4), C6H5SO3ReI(CO)5 (5) und p-CH3—C6H4SO3ReI(CO)5 (6). Die Zusammensetzung und Struktur dieser Verbindungen wurde mit Hilfe von 1H-NMR-, massen- und IR-spektroskopischen Untersuchungen ermittelt.
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  • 198
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 577-592 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Peroxides, IX. Preparation and Thermolysis of tert-Butyl α-Aryloxy- and α-ArylthioperacetatesEleven tert-butyl α-aryloxyperacetates and four tert-butyl α-arylthioperacetates were prepared and characterized by spectra and analyses. The products and rates of their thermolyses are explained by a homolytic fragmentation mechanism. The rates are predominantly influenced by a polar effect. This is supported by the observation of Hammett relations in both series (σ = -1.1 and -1.3).
    Notes: 11 α-Aryloxy-peressigsäure-tert.-butylester und 4 α-Arylmercapto-peressigsäure-tert.-butylester wurden synthetisiert und durch Spektren und Elementaranalysen charakterisiert. Die Thermolyse dieser Peroxide erfolgt durch homolytische Fragmentierung. Ihre Geschwindigkeit gehorcht in beiden Reihen der Hammett-Beziehung mit σ = -1.1 bzw. -1.3 und unterliegt somit einem polaren Effekt.
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  • 199
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 653-660 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Preparation of Fluorocyclotriphosphazenes with Phosphazene Side ChainsFluorocyclotriphosphazenes with phosphazene side chains were prolonged by the alternating reactions of hexamethyldisilazane and phosphorus pentachloride (1-8). The compounds formed contain up to six alternating (PN) bonds. Reactions of heptamethyldisilazane and methylamine give 9 and 10. Substitution reactions with the higher ring compounds yield 11-14. The properties of these substances are described and their structures could be likely prooved on the basis of 31P and 19F n. m. r. investigations. The compounds are further characterized by analysis and i. r. spectra.
    Notes: Fluorcyclotriphosphazene mit Phosphazenseitenkette werden durch alternierende Reaktionen mit Hexamethyldisilazan und Phosphorpentachlorid verlängert (1-8). Dabei entstehen Verbindungen, die bis zu sechs alternierende (PN)-Bindungen enthalten (7, 8). Umsetzungen mit Heptamethyldisilazan und Methylamin ergeben 9 und 10. Substitutionen an höheren Ringverbindungen führen zu 11-14. Die Eigenschaften dieser Substanzen werden beschrieben und ihre Struktur durch 31P- und 19F-NMR-Untersuchungen wahrscheinlich gemacht. Die Verbindungen werden weiterhin durch Analysen und IR-Spektren charakterisiert.
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  • 200
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    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 661-664 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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