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  • 1970-1974  (2,779)
  • 1890-1899
  • 1970  (2,779)
  • Polymer and Materials Science  (1,970)
  • Inorganic Chemistry  (809)
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  • 1970-1974  (2,779)
  • 1890-1899
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Ionic polysaccharides. IV. Free-rotation dimensions for disaccharide polymers. Comparison with experiment for hyaluronic acid (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 811-824 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The root-mean-square end-to-end distance has been calculated for a model allowing free rotation about glycoside bonds for the general case of polysaccharides having a disaccharide repeating unit. Numerical estimates are given for several naturally occurring structures based on an idealized pyranose unit in the C1 chair conformation. Extrapolation procedures which make use of the intrinsic viscosity [η] in good solvents to obtain unperturbed dimensions do not represent, data for hyaluronic acid very well, especially at low molecular weights. However, order-of-magnitude estimates suggest that this polymer behaves similarly to other polysaccharides, and probably has stiffer local structure than typical non-ionic synthetic polymers. A double logarithmic plot of the product of [η] and M̄w, the weight-average molecular weight, against the degree of polymerization in the range for M̄w of 104 to 2 × 104 permits a straight-line fit of available data for all the glycosaminoglycans, including heparin and the chondroitin sulfates, as well as sodium carboxymethyl cellulose. This result suggests similarity of short-chain hydrodynamic behavior of these polymers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090707
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  • 2
    Electronic Resource
    Electronic Resource
    The 4th Jerusalem symposium (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 875-875 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090711
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  • 3
    Electronic Resource
    Electronic Resource
    Masthead (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090801
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  • 4
    Electronic Resource
    Electronic Resource
    Diffusional boundary spreading in the ultracentrifuge (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 865-874 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A common approximation for deriving solutions to the Lamm equation is to neglect diffusion. This paper presents a singular perturbation technique that allows one to estimate the band spreading due to nonzero diffusion coefficient. We illustrate the general mathematical technique by its application to sedimentation when pressure effects are important. Comparison of the approximate solution with accurate numerical solutions shows that the relative errors are of the order of 1% both for concentration and concentration gradient for parameters of chemical interest.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090710
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  • 5
    Electronic Resource
    Electronic Resource
    Role of pH in charging of glycogen (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 891-896 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glycogen acquires a negative charge in both alkaline and acidic solutions and can move in an electrical field, its mobility being related to the degree of alkalinity or acidity. There is a slight increase in relative viscosity at both ends of the pH spectrum. These effects and the changes in nuclear magnetic resonance as a function of pH are interpreted.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090803
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  • 6
    Electronic Resource
    Electronic Resource
    Studies on the viscosity of solutions of bovine liver glutamate dehydrogenase and on related hydrodynamic models; effect of toluene on enzyme association (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 877-889 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The viscosity of bovine liver glutamate dehydrogenase solutions was studied at 10 and 20° C in 0.2.M sodium phosphate buffer at pH 7, in the concentration range 0.1-8 mg/ml. A method for the study of the viscosity of very dilute solutions of associating enzymes is described. It was found that the reduced specific viscosity ηsp/c of glutamate dehydrogenase continuously increases with increasing enzyme concentration, from about 4 ml/g at the lowest concentrations to about 16 ml/g at 8 mg/ml. In the presence of 10-3M GTP and 10-3M NADH the viscosity increase is much smaller and the results can be extrapolated to zero enzyme concentration to yield an intrinsic viscosity [η] = 3.2. The values of ηsp/c in phosphate buffer alone apparently extrapolate to the same value of [η], or to a value close to it. We also observe that, in the presence of toluene ηsp/c increases very much more with enzyme concentration: ηsp/c already equals 16 ml/g at a concentration of 0.75 mg/ml. These observations are in good agreement with the hypothesis that the active oligomer of glutamate dehydrogenase (MW = 312,000) associates with increasing enzyme concentration to form linear rodlike polymers of indefinite length. This association is strongly diminished by the addition of 10-3M GTP, 10-3M NADH. Toluene, on the other hand, promotes reversible association to linear polymers of very high molecular weight. The transverse and axial rotary frictional coefficients of macroscopic bodies, similar to a physical model for the structure of glutamate dehydrogenase recently advanced, were determined. Assuming that the viscosity of the model is equal to that of an ellipsoid of rotation with identical frictional coefficients, we calculate [η] = 3.26 ml/g according to Kuhn and 3.20 ml/g according to Simha, for the glutamate dehydrogenase oligomer, in good agreement with the result derived from the study of enzyme solutions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090802
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  • 7
    Electronic Resource
    Electronic Resource
    Surface chemistry of poly(β-beiizyl L-aspartate) (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 911-922 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular monolaycrs of poly(β-benzyl L-aspartate) spread at. an air-water interface have been studied. The results obtained both by direct observations on the monlayer and from examination of collapsed films with polarized infrared spectroscopy and electron diffraction are consistent with the presence of right handed α-helices in the mono-layer when the molecular weight is high. When 1% (v/v) isopropanol is present in the subphase the right-handed helix prevails, provided that the monolayer is first spread on water. Monolayers of low molecular weight polymer appear to form the crossed-β structure. Orientated collapsed films of high molecular weight polymer can be converted to the left-handed α-helical and to the ω-conformation, and the mechanisms are discussed. The surface chemistry of this polymer is compared with that of related polymers and a consistent pattern of behavior emerges.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090805
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  • 8
    Electronic Resource
    Electronic Resource
    Characterization of acid-denatured DNA by low-angle light scattering (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1017-1028 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low-angle light scattering results reported previously demonstrated that measurements on high molecular weight native DNA must be made at angles below 30° in order to obtain correct molecular weights. Earlier light-scattering data obtained on denaturated DNA at angles above 30° showed no change in molecular weight upon denaturation, even though other techniques clearly showed that strand separation occurred. This paper reports low-angle measurements on solutions of calf thymus and T7 DNA denatured under acidic conditions. The results demonstrate that a halving of molecular weight consistent with strand separation is detected by light scattering only when low-angle data are used to obtain correct molecular weights for native material. As expected from theoretical considerations, the scattering from denatured DNA is a linear function of sin2(θ/2), where θ is the angle of observation. This result shows that anticipated experimental artifacts have no significant effect on the low-angle measurements and demonstrates that the curvature in the scattering envelope observed for native DNA below 30° is an inherent property of the native molecule.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090905
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  • 9
    Electronic Resource
    Electronic Resource
    Kinetics for the transition between cis- and trans-helices in poly-L-prolineA preliminary report of this work was presented at the 156th National Meeting of the American Chemical Society, Atlantic City, New Jersey, September 1968. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1001-1016 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics for the cis-trans isomerization of long-chain poly-L-proline has been studied as a function of pressure, temperature, and solvent composition in the acetic acid + n-propanol solvent system. Our complete kinetic curves were fitted by Monte Carlo techniques, and rate constants for nucleation, growth, and termination were estimated. It was found that for the formation of a cis-helix, high pressure, low temperature, and increased acetic acid content of the solvent, lowered the rate of nucleation relative to growth. The inverse seems to be t rue for the formation of a trans-helix. Molecular models suggest that this behavior of the kinetic constants can be due to the exposure of peptide units to solvent in the transition state for trans nucleation, and the burying of peptide units in the transition state for cis nucleation. It is further suggested from our analysis of complete kinetic curves that at least one of the assumptions usually made in the analysis of relaxation kinetics is invalid for poly-L-proline.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090904
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  • 10
    Electronic Resource
    Electronic Resource
    X-Ray diffraction of ethylenediamine-amylose complex (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1039-1047 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solutions of amylose in ethylenediamine yield a crystalline film complex upon evaporation of solvent. The x-ray analysis indicates the presence of a tetragonal-shaped cell with a symmetry approximating that of space group P212121. The amylose sixfold helix has a diameter of 13.3 Å and a translation period of 8.0Å. Chemical and physical analyses support a complexing ratio of one ethylenediamine molecule to every two glucose units. The structure is nearly identical to any amylose-dimethyl sulfoxide complex previously examined. The square mode of packing arrangement appears to result from complexation between amylose chains. Such complexing indicates a much greater degree of amylose interaction than is observed in amylose complex structures having a hexagonal close-packing arrangement.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090907
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  • 11
    Electronic Resource
    Electronic Resource
    Potentiometric titration of poly-S-carboxymethyl-L-cysteine in aqueous NaCl solution (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1049-1058 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: pH titration measurements of poly- S-carboxymethyl-L-cysteine were undertaken in the aqueous Nacl solution in relation to the β form-random coil transition. The titration curves show a marked molecular weight dependence because of the shortened chain length of materials. Comparison of the optical rotatory dispersion parameter a0 with the titration curve reveals that the titration curve apparently reflects a β structure-random coil transition. The β form of this polymer is assumed to be an intramolecular β form, rather than a β structure stabilized by an intermolecular hydrogen bond, at least in the polymer concentration range considered here. The standard free energy change per amino acid residue for the transition from un-ionized random coil to un-ionized β form is estimated to be about -750 cal/mole residue in the range of 0.005-0.2M NaCl concentration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090908
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  • 12
    Electronic Resource
    Electronic Resource
    Oligonucleotide interactions. III. Circular dichroism studies of the conformation of deoxyoligonucleolides (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1059-1077 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism (CD) spectra of the four usual deoxymononucleosides, all sixteen deoxydinucleotides, and a number of trinucleotides have been measured. The dimer spectra are quite different from the sum of the spectra of their constituent monomers. This indicates the presence of base-stacked conformations analogous to those found for ribonucleoside diphosphates. The CD spectra of several deoxytrinucleotide diphosphates and single-strand f 1 DNA can be calculated fairly well by using a semi-empirical nearest-neighbor approach. There is little or no effect of terminal phosphate or of salt concentration on the optical properties of most deoxy oligomers. The possibility of simultaneous analysis of mixtures of deoxypurine or deoxypyrimidine sequence isomers has been examined. This seems to be a viable approach for the analysis of purine runs but cannot promise much success for pyrimidine runs.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090909
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  • 13
    Electronic Resource
    Electronic Resource
    Oligonucleotide interactions. IV. Conformational differences between deoxy- and ribodinucleoside phosphates (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1079-1103 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism spectra of all 16 ribodinudeoside phosphates containing the bases adenine, uracil, cytosine, and guanine have been measured at room temperature and neutral pH. These results are compared with the circular dichroism spectra of the corresponding deoxy compounds. From the optical properties it is clear that the geometry of the base-stacked conformation of ribo compounds must differ substantially from that of deoxy compounds. Because of this, it is not possible to draw firm conclusions about the relative extent of stacking in most ribo and deoxy compounds. The optical rotatory dispersion of about a dozen deoxy and ribodinucleoside phosphates has been studied as a function of temperature. These results confirmed the conclusions drawn earlier from measurements at a single temperature. Several dinucleoside phosphates containing a 2′ → 5′ phosphodiester bond have also been examined. These compounds have a substantial degree of base stacking at room temperature. The geometry of the stacked conformation is different from that of either the normal ribo dimer or the deoxy dimer. The role of the 2′-hydroxyl group in stabilizing base stacked geometries has been examined by studies on C-2′-O-methyl-pC. This compound has optical properties almost identical to those of CpC. This suggests that the effect of the 2′ hydroxyl is felt indirectly through its perturbation of the geometry of the sugar ring rather than directly by hydrogen bonding. It is not possible at present to identify precise conformational differences among deoxy-, ribo-and 2′ → 5′ ribodinucleoside phosphates.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090910
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  • 14
    Electronic Resource
    Electronic Resource
    Aggregation of poly-L-proline II (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1119-1124 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090912
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  • 15
    Electronic Resource
    Electronic Resource
    The influence of single-strand breaks on the kinetics of denaturation of DNA (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1349-1360 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of single-strand breaks on the kinetics of the relaxation of DNA in a solution of low ionic strength has been investigated by a temperature jump method. The relaxation of DNA after a jump of 0.7 °C in the melting region has been monitored by measuring the extinction at 260 nm. For essentially monodisperse T4 DNA (M = 130 × 106) two distinct relaxation times have been observed, that depend markedly on the initial extent of denaturation 1 - θ. The larger relaxation time decreases from 450 sec to about 300 sec, the smaller one from 55 see to 30 when 1 - θ increases from 0.03 to about 0.8. The dependence of these relaxation times on the average number of single-strand breaks per molecule (p) appears to be very small up to p = 100. However, the relative contribution of the slow process decreases sharply when p increases from 0.6 to 30 and remains nearly constant for larger p. The observations are discussed in the light recent theories of the kinetics of denaturation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360091105
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  • 16
    Electronic Resource
    Electronic Resource
    Electro-optic scattering studies on deoxyribonucleic acid (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1361-1372 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements have been made of the intensity of light scattered from aqueous solutions of calf thymus DNA with and without the application of electric fields. For fields approaching 150 V/cm and frequencies below 2.5 KHz, changes (ΔI) of up to 10% in the residual scattered intensity were observed. In agreement with previous dielectric and electric birefringence measurements, a low frequency dispersion of ΔI was observed, from which a rotary diffusion constant (D) of 1200 s-1 was determined. Interpreting the electric field data in terms of the classical dipolar orientation theory led to values of 2.4 × 10-25 cm (7.4 × 10-14 esu) and 4.3 × 10-25 cm (13 × 10-14 esu) for the permanent dipole moment and the anisotropy of the electric polarisabilities respectively. Furthermore the permanent dipole moment was along the major molecular axis and the particles orientated in the field as rigid entities. The zero field data indicated a molecular shape which was not rodlike but corresponded to the Kratky-Porod “stiffness” parameter of x = 24 for the wormlike coil model. Although curved, the molecules appeared to orientate in low-intensity electric fields as rigid, but not rodlike molecules. The implications of this on recent discrepancies in D determined by two or more dynamic relaxation methods is briefly discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360091106
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  • 17
    Electronic Resource
    Electronic Resource
    Buoyant density and solvation of magnesium DNA (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1391-1402 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The buoyant density of T-4 DNA was determined by equilibrium sedimentation in a density gradient, of mixed solutions of cesium and magnesium chlorides and bromides. The preferential hydration was calculated from these data, allowing appropriately for the exchange equilibrium of DNA with Cs+ and Mg++ ions. The charge and intrinsic solvation of the counterions were found to have no appreciable effect on the hydration of the DNA, the extent of solvation depending only on the thermodynamic, activity of the water. Various reasonable hypotheses are discussed to account for these results.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360091108
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  • 18
    Electronic Resource
    Electronic Resource
    Studies on bacteriophage MS2. VIII. Evidence for dimer formation of MS2 RNA by reaction with formaldehyde at acidic pH (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1373-1389 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 27 SMS2 RNA with formaldehyde normally results in an unfolded, 13.4 S form. At acidic pH, however, and under the proper ionic conditions, a compact component sedimenting at 36-40 S was obtained. The molecular weight of this species corresponds to a dinner. The formaldehyde concentration was not critical, and approximately the same number of base pairs had been opened in the compact and in the unfolded form. Presumably dimers, which had been specifically formed under defined conditions, were stabilized by formaldehyde-induced crosslinks. Similar dimers were formed by 16 S and by 23 S ribosomal RNA, but not by tRNA.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360091107
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  • 19
    Electronic Resource
    Electronic Resource
    Volume changes accompanying thermal denaturation of deoxyribonucleic acid. II. Denaturation at alkaline pH (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 445-457 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The change in apparent molal volume φ of DNA on thermal denaturation in carbonate buffer at pH 11.0 has been determined by the dilatometric method. It was found that φ increases sigmoidally during the helix-coil transition. Several methods, including a colorimetric technique that closely simulates the conditions used in the dilatometric experiments, were employed to estimate the protons lost by the DNA during the transition. These measurements indicated that the extent of the proton loss depends on the counterion present, increasing in the order Li+ 〈 Na+ 〈 K+ 〈 Cs+. The major part of the volume changes observed during the denaturation is due to the volume changes expected to accompany the transfer of protons from the bases guanine and thym ne to carbonate ions. As has been previously reported for the denaturation of DNA at neutral pH, the volume change directly due to the change in shape of the polymer molecules is so small as to be experimentally undetectable.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090407
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  • 20
    Electronic Resource
    Electronic Resource
    Location of proline derivatives in conformational space. II. Theoretical optical activity (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 569-588 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of theoretical optical calculations with experimental data provides a check of the validity of the theory or provides conformational information. The theory was validated by studies in which the approximate conformation was located independently. These studies have shown that a theory restricted to the two lowest energy transitions for each chromophore gives qualitative agreement with experiment. On the other hand, for some of the proline derivatives, the theoretical treatment allows detailed conformational assignments. Both successes and failures in correlating theory with experiment are discussed. The results presented provide a basis for assessing the prospects for relating protein and polypeptide optical activity to their conformations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090503
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  • 21
    Electronic Resource
    Electronic Resource
    Ethidium bromide-DNA complex: Wavelength dependence of pyrimidine dimer inhibition and sensitized fluorescence as probes of excited states (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 639-653 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethidium bromide inhibits the formation of ultraviolet-induced pyrimidine dimers in DNA. The efficiency of dimer inhibition increases with increasing energy of the exciting photons. The efficiency of energy transfer from the DNA singlet to the dye singlet, as monitored by sensitized fluorescence, is independent of wavelength. The efficiency of singlet-singlet transfer agrees with that for dimer inhibition at photon energies corresponding to excitation of the lowest singlet state of DNA. Our results support a model in which dimers are formed both directly from the singlet state and also from the triplet state, with triplets arising from higher vibrational levels of the singlet.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090603
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  • 22
    Electronic Resource
    Electronic Resource
    Testing of A size criterion for DNA-hydrocarbon binding (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 689-696 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intercalation model of DNA-hydrocarbon binding appears reasonable, but rests on indirect evidence only. To test the model, a size criterion for binding has been proposed. The size criterion is based on the assumption that hydrophobic forces play a major role in the binding of hydrocarbons to DNA. It states that hydrocarbons which are small enough to intercalate into DNA and be well protected from contact with the medium, will be found to bind to DNA; those that are too large will not. We report results on the binding of fourteen polycyclic aromatic hydrocarbons to DNA. Predictions based on the size criterion were found to be valid in all cases tested.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090607
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  • 23
    Electronic Resource
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    Cooperative binding of adenosine by polyuridylic acid: A further analysis (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 697-715 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dialysis data of Huang and Ts'o for the cooperative binding of adensine to polyuridylic acid are analyzed here using a grand-partition function Ising model method similar to that originally employed for polyelectrolytes by Rice and Nagasawa. An appropriate modification permitting the treatment of the sliding degeneracy of the two polyuridylic acid strands is also included. In addition to the previously estimated stacking energy of about -6 kcal/mole one also obtains the free energy change F̄ for the transfer of a single adenosine molecule from a fixed site in solution to a fixed site on the polyuridylic acid. This binding energy falls in the range F̄ = -140 to +620 cal/mole, indicating that binding in the 1:2 (purine: pyrimidine) complex is either very weak or repulsive. The absence of any comparable cooperative stacking of adenosines in solution at the same concentration together with the likely repulsive character of the binding implies that the stacking energy must contain a significant contribution from other processes than simple stacking of adenosines. A generalization of the theory to treat multicomponent binding and longer-range interactions is effected, and the form applicable to simultaneous binding of both adenosine and guanosine by polyuridylic acid is presented.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090608
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  • 24
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    PMR chemical shifts of TFA in poly(γ-benzyl L-glutamate) solutions (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 739-744 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present communication describes a new way of studying helix-random coil transformations of polypeptide, poly-(γ-benzyl L-glutamate), in benzene-trifluoracetic acid (TFA) and chloroform-TFA systems. The difference between the PMR chemical shift of TFA with and without the polypeptide, measured as Δ, may be used to follow the conformational transition. This technique is particularly useful for concentrated solutions, where the PMR peaks of the polymer are so broad that no valuable information may be derived. As the TFA content increases in the system (at constant polymer concentration), Δ decreases normally whether the polymer is helical or random. However, Δ changes in a different way in the helix-random coil transition region, and actually increases with increasing TFA content. This peculiar behavior is explained in terms of the solvation of the helix and random coil structures.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090610
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  • 25
    Electronic Resource
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    NMR study of the slowly exchanging hydrogens of 640 Å steerskin collagen (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 745-748 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090611
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  • 26
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    Solution properties of synthetic polypeptides. VI. Helix-coil transition of poly-N5-(3-hydroxypropyl)-L-glutamine (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 717-738 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new procedure for evaluating u and σ characterizing σ-helix-forming polypeptides in solution was derived from Nagai's theory for the helix-coil transition of such polymers. Here u is the activity for helix formation from random coil, and σ is the helix initiation parameter. The necessary data are the helical content fN at fixed solvent and temperature as a function of N, where N is the degree of polymerization of the polypeptide sample. Such data were obtained from ORD measurements on a number of fractionated samples of poly-N5-(3-hydroxypropyl)-L-glutamine (PHPG) in mixtures of water and methanol covering the complete range of composition and at various termperatures (5-40°C). When analyzed in terms of the proposed procedure, they yielded values of σ which were in the range (3.2 ± 0.6) × 10-4, substantially independent of solvent composition and temperature. These values were much larger than those obtained recently for σ of poly(β-benzyl-L-aspartate) in m-cresol and in a mixture of chloroform and DCA. The data for [η] and s0 (limiting sedimentation coefficient) as functions of molecular weight indicated that the molecular shape of PHPG in pure methanol is essentially rodlike, whereas that in pure water is not entirely randomly coiled but rather may be regarded as an interrupted helix. These indications were consistent with the results from ORD measurements. When plotted against the corresponding values of fN, the values of [η] and [s0] for PHPG in mixtures of water and methanol of various compositions and temperatures formed smooth composite curves, and we attributed these phenomena to the fact that σ of PHPG was nearly constant under these solvent conditions. Here [s0] stands for a reduced limiting sedimentation coefficient which is equal to the inverse friction factor of the solute molecule.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090609
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  • 27
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    Electronic Resource
    Masthead (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090701
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  • 28
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    Interaction of nucleic acids. VI. Interaction of purine with nucleic acids (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 765-782 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction of purine with DNA, tRNA, poly A, poly C, and poly A. poly U complex was investigated. In the presence of purine, the nucleic acids in coil form (such as denatured DNA, poly A and poly C in neutral solutions, or tRNA) have lower optical rotations. In addition, hydrodynamic studies indicate that in purine solutions the denatured DNA has a higher viscosity and a decreased sedimentation coefficient. These findings indicate that through interaction with purine, the bases along the poly-nucleotide chain are unstacked and are separated farther from each other, resulting in increased assymmetry (and possibly volume) of the whole polymer. Thus, the de-naturation effect of purine reported previously can be explained by this preferential interaction of purine with the bases of nucleic acids in coil form through a hydrophobic-costacking mechanism. Results from studies on optical rotation and helix-coil transition show that the interaction of purine is greater with poly A than with poly C. The influence of temperature, Mg++ concentration, ionic strength, and purine concentration on the effect of purine on nucleic acid conformation has also been investigated. In all these situations the unraveling of nucleic acid conformation occurs at much lower temperatures (20-40°C lower) in the presence of purine (0.2-0.6M).
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090703
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  • 29
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    Configurational statistics of polysaccharide chains. Part II. CelluloseContribution No. 286 from Centre of advanced study in physics, University of Madras, India. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 783-790 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characteristic ratio of unperturbed cellulose chain was computed as a function of the angle τ at, the bridge oxygen atom and the degree of polymerization. Very high values of the order of 40 or more, depending on the angle at the bridge oxygen atom, have been obtained for this ratio, indicating that cellulose chains are highly extended. The average dimensions of cellulose chains are found to be sensitive even for small changes in the angle at the bridge oxygen, and these chains attain the character of a random coil in very high molecular weight range (degree of polymerization greater than 2000). The large differences in the unperturbed dimensions of cellulosic chains observed in different solvents have been attributed to the possible small changes in the angle τ caused by specific solvent, interactions.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090704
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  • 30
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    Effect of side-chain hydrophobic bonding on the stability of homopolyamino acid α-helices: Conformational studies of poly-L-leucine in waterPresented before the Division of Biological Chemistry at the 154th National Meeting of the American Chemical Society, Chicago, Illinois, September 1967. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 749-764 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational properties of block copolymers of poly-L-leucine in water have been examined. The degree of polymerization of the poly-L-leucine block was 11 and 21, respectively, for samples prepared by the Merrifield procedure, and 56 for a sample prepared by the polymerization of leucine N-carboxyanhydride. The optical rotatory dispersion parameter b0 was used to obtain the helix content θh at various temperatures. Application of the Lifson-Roig theory gave the following parameters for the transition of a residue from a coil to a helical state: v = 0.05-0.011, ΔH = +100 cal/mole, ΔS = +0.70-1.00 e. u. These parameters, as well as those for other polyamino acids, are accounted for by hydrophobic bonds involving the nonpolar side chains in the helical and randomly coiled forms. From the data for poly-L-alanine and theoretical values of the thermodynamic parameters for hydrophobic bond formation, the parameters for formation of a polyglycine helix are computed. By separating the contributions of the backbone, it is possible to obtain a set of thermodynamic parameters for the side-chain contributions of a number of polyamino acids. Increased size of the nonpolar side chain (with a larger contribution from hydrophobic bonding) makes a larger contribution to the stability of the α-helix which is reflected, among other ways, in a higher helix content at given temperature.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090702
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  • 31
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    Polymerization of amino acid derivatives by polymer catalysts. V. Polymerization of DL-β-phenylalanine N-carboxyanhydride by several poly(N-alkylamino acid) diethylamides (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 791-797 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of DL-β-phenylalanine N-carboxyanhydride (NCA) initiated by poly(N-benzylglycine)diethylamide (DEA) and poly(N-methyl-DL-alanine)DEA has been investigated. As previously reported, polysarcosine DEA, poly-N-ethylglycine DEA, and poly-N-n-propylglycine DEA showed marked accelerations in the polymerization of DL-β-phenylalanine NCA as compared with the polymerization initiated by low molecular weight, amines having similar base strength. However, this phenomenon (the chain effect) was not observed with the two polymer catalysts studied in the present investigation With poly-N-methyl-DL-alanine DEA, adsorption of DL-β-phenylalanine NCA onto the polymer chain takes place, though not so effectively as with other polypeptides, so the absence of chain effect was ascribed to a reduced flexibility of the polymer chain. With poly(N-benzylglycine)DEA, the reactivity of terminal base group was found to be much lower than that of other polymer catalysts. However, the absence of the chain effect would be attributed to the rigidity of polymer chain of poly-N-benzylglycine DEA due to the bulkiness of the N-benzyl group.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090705
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  • 32
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    Ionic polysaccharides. III. Dilute solution properties of hyaluronic acid fractions (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 799-810 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular weights by osmometry (M̄n), light scattering (M̄w), and sedimentation-diffusion (MsD) were determined for selected fractions and unfractionated samples of hyaluronic acid in the molecular weight range 3 × 104-1.7 × 106. For the determination of MsD from the sedimentation coefficient s, a calibration procedure based on the data of Laurent, Ryan, and Pietruszkiewicz gave the following relations in 0.2M NaCl: log (s-1)0 = 14.681 - 0.413 log MsD and log D0 = -3.828 - 0.568 log MsD, where subscript, zero refers to zero concentration and D is the diffusion coefficient. The average Mandelkern-Flory parameter β in 0.2M NaCl is 3.0 × 106. Data for the intrinsic viscosity [η] may be fitted for M 〉 105 by [η] = K′Ma, where K′, a are in 0.2M NaCl, 0.0228, 0.816; in 0.5M NaCl, 0.0318, 0.777; in 0.1 M HCl, 0.0279, 0.763, respectively. Below M = 105, [η] appears to fall below the values calculated, possibly due to non-Gaussian behavior of short chains. The second virial coefficient A2 in 0.5M NaCl approaches the ideal Donnan value, decreasing slightly with increasing molecular weight. The friction parameter P is about 20% smaller than that of uncharged polymers of similar dimensions. The flexible coiling nature of this polymer is confirmed.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090706
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  • 33
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    Sedimentation of ribosomal ribonucleic acid from ribonuclease treated and untreated ribosomes (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 843-864 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formation of a slowly sedimenting form of 23-S ribosomal RNA from E. coli has been investigated by analytical ultracentrifugation and thermal denaturation in aqueous solution and in formamide. Evidence is presented that the slow form of 23-S arises as a result of nucleate damage to the RNA in the 50-S ribosome. The 30-S ribosome (and 16-S RNA), is unaffected. The slow form of 23-S RNA cannot be demonstrated under conditions of complete denaturation in formamide, but only by partial denaturation in aqueous solution of low ionic strength (〈 0.01M Na). Apparent maintenance of the integrity of 23-S RNA in formamide after nuclease treatment suggests that this may not be a simple linear molecule. An alternative model is suggested containing a circular element in the structure.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090709
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  • 34
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    Mechanochemical study of wet-spun lithium-DNA fibers (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 825-842 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uniform LiDNA fiber specimens of nearly 20 m length have been prepared with a wet-spinning method developed by the author. Samples immersed in the spinning bath (80% ethyl alcohol containing 0.4M LiCl) have been subjected to mechanochemical study involving stretching, relaxation, and contraction measurements. A special technique was developed to transfer the sample from the Teflon-coated cylinder used in spinning to the sample column of the mechanochemical apparatus without stretching or removing the sample from the spinning bath. Force-strain curves of samples consisting of two fiber bundles showed an initial region of low slope followed by a region of high slope and a second region of low slope up to rupture. Some thicker specimens showed an aging effect which abolished the initial low-slope region and was interpreted as indicative of crystallization. Force-strain curves of two-bundle samples showed a strong influence of temperature with a complete loss of tensile strength of the LiDNA fibers in the spinning bath at about 55°C. Furthermore, samples at zero strain exhibited a contractile force when subjected to temperatures above about 40°C; the contractile process was pronounced with samples kept above 48°C. On contraction these samples obtained a zero-force length 20-30% of the original. These data are taken as evidence for a helix-to-coil transition occurring in the DNA, the low melting temperature being caused by the chemical influence of the ambient aqueous alcohol-LiCl bath.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090708
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  • 35
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    Low-angle light-scattering studies on alkali- and heat-denatured DNA (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1029-1038 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular weight of native DNA is shown to decrease by at least a factor of two on denaturation by heat or alkali. This result is obtained only if low-angle (〈30°) light-scattering measurements are used. High-angle measurements (〉30°) do not reveal a decrease in molecular weight on denaturation due to the incorrect value for native DNA. The dn/dc value for both native and denatured DNA is 0.166 ml/g ± 0.003 ml/g. Methods are described for the clarification of native and denatured DNA solutions for light scattering by the use of membrane filters.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090906
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  • 36
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    Electric dichroism studies: Interaction of trifluoroacetic acid with poly(gamma;-benzyl L-glutamate) (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 991-1000 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electric dichroism studies on poly(γ-benxyl L-glutamate) show that the addition of small amounts (up to 5%) of trifluoroacetic acid causes complete disappearance of dichroism in contrast to the electric birefringence, which drops to an observable plateau at 20% of its initial value. This loss of dichroism cannot be explained simply by a decrease in the effective dipole moment of the benzyl ester side chains, and the nature of this interaction is explored by nuclear magnetic resonance and infrared spectral studies. Theories of the helix-coil transition which require an initial protonation of the helix backbone to form a more flexible rod consisting of helical segments interrupted by regions of random coil are shown to be inadequate to describe the changes in poly(γ-benzyl L-glutamate) effected by small amounts of trifluoroacetic acid. Rather, trifluoroacetic acid in small amounts interacts with the ester carbonyl oxygen in the side chain, either by hydrogen bonding or protonation, before there is evidence of any effect on the backbone or of loss of helix content.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360090903
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  • 37
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    Raman spectra of poly-L-lysines (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1229-1237 
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    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-L-lysine hydrochloride and poly-∊-carbobenzoxy-L-lysine in the solid state have been obtained and are consistent with the presence of an α-helical structure. The Raman spectrum of poly-L-lysine in aqueous solution suggests the presence of random coil structures.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360091003
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  • 38
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    Backbone and side-chain conformations of amino acids and amino acid residues in peptidesContribution No. 288 from the Centre of Advanced Study in Biophysics, University of Madras, Guindu Campus, Madras-25, India. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1249-1252 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360091005
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  • 39
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    Masthead (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360091101
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  • 40
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    Conformational studies of linear β-D-1,4′-mannan and galactanContribution No. 289 from the Centre of Advanced Study in Physics, University of Madras, Madras, India. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1239-1247 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nonbonded interaction energy of disaccharides, mannobiose and galactobiose and polysaccharides mannan and galactan have been computed as a function of dihedral angles (φ,ψ). The conformation (40°, -20°) has been preferred for the mannan chain from nonbonded interaction energy considerations. The O5…O3′ type of intramolecular hydrogen bond has been found to be possible in the above conformation. Comparison of the allowed region of mannan with those of cellulose and xylan indicates that the monomer unit, in mannan chain has slightly higher freedom of rotation than that of cellulose and less than that of xylan. As in cellulose and mannan, the freedom of rotation of the monomer units in β-1,4′ galactan is highly restricted. Unlike mannan (which prefers an extended conformation) the β-1,4′ galactan prefers a helical conformation similar to amylose. Just as in amylose the O2…O3′ type hydrogen bond between contiguous residues is also possible in β-1,4′ galactan.
    Additional Material: 7 Ill.
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  • 41
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    Perspectives report: Melting of DNA: Its study and application as a research methodWe are delighted to include this article in Biopolymers since it includes the important Russian literature in this area. The Editors. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1253-1306 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 23 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1970.360091102
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  • 42
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    Critical comparison of the experimental optical activity of helical polypeptides and the predictions of the molecular exciton model (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1475-1502 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The predictions of the presently accepted molecular exciton model for the optical activity of helical polypeptides are in reasonable agreement with experimental spectra in the accessible wavelength range. However, crucial verification requires the detect of a significant negative rotatory hand just below the accessible range. A computer-oriented method is utilized to obtain information concerning the inaccessible range. Optical rotatory dispersion computed by evaluation of the Kronig-Kramers integral transform from the experimentally determined circular dichroism of several helical homopolypeptides in solution are compared with the experimentally determined optical rotatory dispersion. Computed and experimental curves are congruent within an uncertainty approaching that of the experimental technique, whatever the polypeptide sample lot, side chains, and solvent. It is shown that t his agreement is not a computational or experimental artifact. These results can be interpreted in two ways: (1) that the predicted band does not exist, and (2) that the perturbation of the predicted band is being negated by other inaccessible bands in the vacuum ultraviolet. Arguments are presented to show that the first of these two possibilities is more probable.
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    URL: http://dx.doi.org/10.1002/bip.1970.360091209
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  • 43
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    Electrophoretic charge of a cylindrical macroion in aqueous 1 : 1 electrolyte (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1511-1530 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential problem is formulated for rodlike macroions and reduced to a single dimensionless equation with appropriate boundary conditions. A method of solution based on piecewise linearization of the potential equation is detailed and compared with two other approaches. It is suggested that the present method yields improved estimates of macroion charges. Some numerical results are included, and the relation between electrophoretic charge and macroion charge is considered.
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    Darstellung und Eigenschaften von Fluormethyl-dialkyl-aminen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 104-111 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of FluoromethyldialkylaminesFluoromethyldialkylamines (3a-f) are prepared from N,N-acetals (aminals) by cleavage with carboxylic acid fluorides or l-fluoro-2,4-dinitrobenzene. They are low-boiling liquids and are characterized by a covalent carbon-halogen bond. Their reactivity is similar to that of the analogous carbimonium chlorides, bromides and iodides.
    Notes: Fluormethyl-dialkyl-amine (3a-f) werden durch Spaltung von Aminalen mit Carbonsäurefluoriden oder l-Fluor-2.4-dinitro-benzol gewonnen. Sie sind niedrigsiedende, durch eine kovalente Kohlenstoff-Halogen-Bindung charakterisierte Flüssigkeiten und zeigen ähnliche Reaktionsfähigkeit wie die analogen Carbimoniumchloride, -bromide oder -jodide.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030117
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    Heterosubstituierte Fulvene, IV Im 5-Ring unsubstituierte 6.6-Diamino-fulvene (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 133-146 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Fulvenes, IV In the 5-Membered Ring Unsubstituted 6,6-DiaminofulvenesAlkylation of tetrasubstituted thioureas with methyl iodide leads to S-methyl isothiuronium iodides 3, which have been transformed to 6,6-diaminofulvenes 1 by condensation with cyclopentadienyl sodium. Some compounds of type 1 are also obtainable from the reaction between cyclopentadiene and chloroformamidinium chlorides 4 in the presence of triethylamine. I.r., u.v., and n.m.r. spectra of 1 and 3 are discussed.
    Notes: Tetrasubstituierte Thioharnstoffe lassen sich mit Methyljodid in die S-Methyl-isothiuroniumjodide 3 überführen, die ihrerseits mit Cyclopentadienylnatrium die 6.6-Diamino-fulvene 1 bilden. Einzelne Vertreter von 1 sind auch aus Cyclopentadien und Chlorformamidinium-chloriden 4 in Gegenwart von Triäthylamin zugänglich. Die IR-, UV- und NMR-Spektren von 1 und 3 werden diskutiert.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030120
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  • 46
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    Über Vinylsulfonyl-methylide (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 183-192 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: VinylsulfonylmethylidsThe preparation of dimethylsulfonio-(vinylsulfonylphenylsulfonylmethanide) (5), triphenyl-phosphonio-(vinylsulfonylphenylsulfonylmethanide) (6) and triphenylphosphonio-(vinyl-sulfonylbenzoylmethanide) (8) is described. The u. v. spectra of 5 and 6 are similar to the u.v. spectrum of the bis(phenylsulfonyl)methane anion (9). Because of the interaction of the SO2-groups with the ylide carbanions, the SO2-stretching frequencies compared to those of vinylsulfonylphenylsulfonylmethane (4) are shifted 20 -30/cm to lower wave numbers. This interaction causes a higher electron density in the vinyl groups of the ylids compared to 4, as shown by n. m. r. measurements. The mass spectra of 5, 6 and 8 are discussed.
    Notes: Die Synthese von Dimethylsulfonio-[vinylsulfonyl-phenylsulfonyl-methanid] (5), Triphenyl-phosphonio-[vinylsulfonyl-phenylsulfonyl-methanid] (6)undTriphenylphosphonio-[vinyl-sulfonyl-benzoyl-methanid] (8) wird beschrieben. Die Elektronenspektren von 5 und 6 sind mit dem UV-Spektrum des Bis-phenylsulfonyl-methan-Anions (9) vergleichbar. Durch Wechselwirkung der SO2Gruppen mit den Ylidcarbanionen werden die SO2-Valenzschwingungsfrequenzen im Vergleich zu Vinylsulfonyl-phenylsulfonyl-methan (4) um 20 - 30/cm zu kleineren Wellenzahlen verschoben. Diese Wechselwirkung bedingt eine höhere Elektronendichte in den Vinylgruppen der Ylide als bei 4, was NMR-spektroskopisch nachweisbar ist. Die Massenspektren von 5, 6 und 8 werden diskutiert.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19701030125
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    Umsetzungen von Cyclopentadienonen mit aliphatischen Diazoverbindungen, 6 Versuche mit „Indanocyclon“ (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 173-182 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyclopentadienones with Aliphatic Diazo Compounds, 6 Experiments with „Indanocyclone“„Indanocyclone“ 3, prepared from ninhydrin (1) and dibenzylketone (2), reacts with an ethereal diazomethane solution to form an 1 :1-adduct 4a and two isomeric 1 : 2-adducts, presumably 12 and 13. Elimination of N2 from 4a leads to the formation of the cyclopropane 7, the fluorenone 6 and, by way of phenyl migration, the new cyclone 8a; elimination of N2 from 12 and 13 leads to undefined products. 5 is converted via its hydrazone into the diazo compound 10. Ring enlargement of 6 with diazomethane produces the phenanthrene 9.Reaction of diazoethane with 3 gives the instable 1 :1-adduct 4b, which yields the new cyclone 8b by N2-elimination and phenyl migration. 8b also forms an 1 :1-adduct (11?). Phenyl diazomethane adds to 3 giving a rather stable 1 :1-adduct 14, the isomeric 16 and the epoxide 15. Elimination of N2 from 14 yields the fluorenone derivative 17, which upon treatment with excess diazomethane undergoes ring enlargement to form the phenanthrene derivative 18.
    Notes: Das aus Ninhydrin(l)und Dibenzylketon(2) erhältliche, Indanocyclon‘ 3 gibt mit ätherischer Diazomethanlösung ein 1 :1-Addukt 4a und zwei isomere 1 : 2-Addukte, vermutlich 12 und 13. 4a zerfällt unter N2-Abspaltung zum Cyclopropanderivat 7, zum Fluorenonderivat 6 und unter Phenylwanderung zum neuen Cyclon 8a; 12 und 13 geben bei der N2-Abspaltung keine definierten Produkte. Aus 5 wird über sein Hydrazon die Diazoverbindung 10 und mit Diazomethan unter Ringerweiterung das Phenanthrenderivat 9 erhalten.Mit Diazoäthan entsteht aus 3 das instabile I :1-Addukt 4b, das bei der N2-Abspaltung unter Phenylwanderung das Cyclon 8b bildet; dieses gibt erneut ein Diazoathan-Addukt (11?).Mit Phenyldiazomethan liefert 3 ein ziemlich stabiles 1 :1-Addukt 14 und sein Isomeres 16 sowie das Epoxid 15. Bei der N2-Abspaltung entsteht aus 14 das Fluorenonderivat 17, das mit Diazomethan zum Phenanthrenderivat 18 ringerweitert wird.
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    URL: http://dx.doi.org/10.1002/cber.19701030124
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    Orthoamide, X Reaktionen vinyloger Amidacetale, Aminalester und Amidaminale (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 222-235 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, X: Reaction of Vinylogous Amide Acetals, Aminalesters and Amide AminalsDerivates of vinylogous orthoformic acid amides react with Grignard compounds to give l,3-bis(dimethylamino)-l-alkenes (4-7), with methylene active compounds to give derivates of N.N-disubstituted 4-amino-l,3-butadienes (17  - 29) and with primary aromatic amines to form vinylogous, N,N,N′-trisubstituted amidines (31-36, 38-40).
    Notes: Vinyloge Orthoameisensäureamid-Derivate geben mit Grignard-Verbindungen 1.3-Bis - dimethylamino-alkene-(l) (4-7), mit methylenaktiven Verbindungen N.N-disubstituierte 4 - Amino-butadien-(l.3)-Derivate (17-29) und mit primären aromatischen Aminen vinyloge N.N.N′-trisubstituierte Amidine (31-36, 38-40).
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030130
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    Masthead (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030201
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  • 50
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    Über Pyrimidine, VIII Darstellung und Eigenschaften von Uracil-carbaldehyd-(4)-hydrazon Der erste Innerkomplex eines Pyrimidins mit Kupfer (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 17-22 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrimidines, VIII Synthesis and Properties of Uracil-4-carbaldehyde Hydrazone. The First Inner Orbital Complex of a Pyrimidine with CopperUracil-4-carbaldehyde (1) reacts with stoechiometric amounts of hydrazine to yield the azine 2. Under mild conditions (30 per cent hydrazine, room temperature) the azine is cleaved to uracil-4-carbaldehyde hydrazone (3). This cleavage by hydrazine is typical for the azomethine group in position 4 of the uracil ring. In aqueous or aqueous-alcoholic solution 3 reacts readily with aliphatic, aromatic and heterocyclic aldehydes to form mixed azines in good yield. With copper(II)-acetate 3 yields in aqueous solution a new type of symmetrical inner orbital complex in which the ratio of pyrimidine to copper is 2 :1. The crystalline and insoluble paramagnetic complex 13 presumably has a planar structure. Substitution of the amino group, even with a methyl group, prevents complex formation. 13 is decomposed by mineral acids to the respective copper salt and azine 2. In analogy to 1 2-thiouracil-4-carb-aldehyde forms the corresponding hydrazone 12.
    Notes: Uracil-carbaldehyd-(4) (1) liefert mit stöchiometrischer Menge Hydrazin das symmetrische Azin 2, welches unter milden Bedingungen (30proz. Hydrazin, Raumtemperatur) zum Uracil-carbaldehyd-(4)-hydrazon (3) gespalten wird. Die schonende Hydrazinolyse ist spezifisch für die Azomethingruppe in 4-Stellung des Uracilrings. 3 liefert in wäßriger bzw. Wäßrig-alkoholischer Lösung mit aliphatischen, aromatischen und heterocyclischen Aldehyden in guter Ausbeute gemischte Azine. Mit Kupfer(II)-acetat bildet 3 einen neuartigen symmetrischen Innerkomplex der Art Pyrimidin : Kupfer = 2:1. Analog zu Uracil-carb-aldehyd-(4) (1) erhält man aus 2-Thio-uracil-carbaldehyd-(4) mit Hydrazin das entsprechende Hydrazon 12.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030104
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    Die Kristallstruktur des 1.2.3.4.4a.9a-Hexahydro-4a.9-propano-carbazolium-hydrobromids (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 46-49 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure of l,2,3,4,4a,9a-hexahydro-4a,9-propanocarbazolium HydrobromideThe crystal structure of the title compound has been determined by X-ray structure analysis. From these results a twist angle of 64.5° of the orbital of the nitrogen is derived.
    Notes: Auf röntgenographischem Weg wurde die Kristallstruktur der Titel-Verbindung bestimmt. Aus den so erhaltenen Ergebnissen resultiert ein Verdrillungswinkel des Orbitals am Stickstoff von ϕpH = 64.5°.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030109
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  • 52
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    Bildungsenthalpie von Wolframhexafluorid und Wolframpentafluorid (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 76-81 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Enthalpy of Formation of Tungsten Hexafluoride and Tungsten PentafluorideThe heat evolved on combustion of tungsten and tungsten pentafluorid in fluorine was measured in a bomb calorimeter. The enthalpies of formation calculated from these values were found to be ΔH°298(WF6, g) = -411.7 ± 0.5 kcal mol-1 and ΔH°298 (WF5, c) -346.1 ± 2.6 kcal mol-1.
    Notes: Die Verbrennungswärmen von Wolfram und Wolframpentafluorid in Fluor wurden in einem Bombenkalorimeter gemessen. Die aus den Meßdaten errechneten Bildungsenthalpien betragen ΔH°298(WF6, gas) -411.7 ± 0.5 kcal Mol-1 und ΔH°298(WF5, fest) -346.1 ± +2.6-1.0 kcal Mol1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030113
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    Anorganische Ringe, III Cyclische Silyl-alkylidenphosphorane (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 97-103 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Inorganic Small Ring Compounds, III Cyclic Silyl-alkylidene PhosphoranesA simple method has been deviced for the synthesis of silyl-substituted alkylidene phosphoranes of the type F. Two members of this series, [(CH3)3PCSi(CH3)2]2 (1) and [( PCSi(CH3)2]2 (2), were prepared from methylene trimethyl and methylene tri-n-butyl phosphorane, resp., and dimethyl dichlorsilane and characterized by means of chemical analysis and n. m. r. spectroscopy. The pathway of the reactions is discussed and a possible mechanism confirmed by an independent preparation of the most likely intermediates. Among these the difunctional open-chain ylid 4, (CH3)3P= CH=Si(CH3)2=CH = P(CH3)3, is of special interest.
    Notes: Ein einfaches Darstellungsverfahren ermöglicht die Synthese von Silyl-alkylidenphosphoranen mit viergliedrigem Ringsystem des Typs F. Zwei Vertreter dieser Reihe, [(CH3)3PCSi(CH3)2]2 (1) und [(n-C4H9)3PCSi(CH3)2]2 (2), wurden aus Trimethyl-methylen- bzw. Tri-n-butyl-methylen-phosphoran und Dimethyldichlorsilan in guten Ausbeuten erstmals hergestellt und analytisch und NMR-spektroskopisch charakterisiert. Der Reaktionsablauf der Synthese wird diskutiert und durch die getrennte Darstellung möglicher Zwischenprodukte belegt. Unter letzteren ist das offenkettige difunktionelle Ylid 4, (CH3)3P=CH  -  Si(CH3)2  -  CH - P-(CH3)3, von Bedeutung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030116
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    Heterosubstituierte Fulvene, V Im 5-Ring negativ substituierte 6.6-Diamino-fulvene (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 147-155 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Fulvenes, V 6,6-Diaminofulvenes with Electronegative Substituents in the 5-Membered RingCondensation of tetramethyl chloroformamidinium chloride (5) with methoxycarbonyl-, bis(methoxycarbonyl)-, and cyanocyclopentadienyl salts leads to the correspondingly substituted 6,6-bis(dimethylamino)fulvenes 6, 7 and 8. Vilsmeier formylation of 6,6-bis(dimethyl-amino)fulvene yields the diformyl derivatives 9 and 11. Structure elucidation of the fulvenes obtained is based on spektroscopic data; the temperature dependence of the n.m.r. spectra is discussed.
    Notes: Tetramethyl-chlorformamidinium-chlorid (5) bildet mit Methoxycarbonyl-, Bis-methoxy-carbonyl- und Cyan-cyclopentadienylsalzen die im 5-Ring entsprechend substituierten 6.6-Bis-dimethylamino-fulvene 6, 7 und 8; Vilsmeier-Formylierung des 6.6-Bis-dimethylamino-fulvens liefert zwei Diformyl-Derivate 9 und 11. Die Strukturzuordnung der erhaltenen Fulvene erfolgt spektroskopisch; die Temperaturabhängigkeit der NMR-Spektren wird diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030121
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    Über Verbindungen mit Urotropin-Struktur, XLVI Synthese des 6-Thia-1.3-diaza-adamantan-Ringsystems (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 205-209 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Compounds with Urotropin Structure, XLVI Synthesis of the 6-Thia-l,3-diazaadamantane Ring System.A synthesis of the hitherto unknown 6-thia-l,3-diazaadamantane ring system starting from N-benzenesulfonyl-diallylamine (1), is described. The first stage of the synthesis is the sulfurdichloride addition to 1, resulting in Nbenzenesulfonyl-2,6-bis(chloromethyl)thiomorpho-line (2).2 was converted with alkali into N-benzenesulfonyl-2,6-dimethylenethiomorpholine (6) and subsequently oxidized to the sulfone 7. Addition of benzylamine followed by removal of the benzyl and the benzenesulfonyl groups yielded 9-thia-3,7-diazabicyclo[3.3.l]nonane 9,9-dioxide (11), which reacted with formaldehyde to produce 6-thia-l,3-diazaadamantane 6,6-di-oxide (12).
    Notes: Ausgehend von Benzolsulfonsäure-diallylamid (1) wird das bisher noch unbekannte 6-Thia-1.3-diaza-adamantan-Ringsystem synthetisiert, wobei im ersten Schritt die Schwefeldichlorid-Addition an 1 zu 4-Benzolsulfonyl-2.6-bis-chlormethyl-thiomorpholin (2) erfolgt. 2 wurde mit Alkali in 4-Benzolsulfonyl-2.6-dimethylen-thiomorpholin (6) und durch anschließende Oxydation in das Sulfon 7 übergeführt. Benzylamin-Addition an 7 und anschließende Abspaltung des Benzyl- und Benzolsulfonyl-Restes führte zum 9-Thia-3.7-diaza-bicyclo[3.3.1]-nonan-9.9-dioxid (11), das mit Formaldehyd das 6-Thia-s-l.3-diaza-adamantan-6.6-dioxid (12) lieferte.
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    URL: http://dx.doi.org/10.1002/cber.19701030128
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    Orthoamide, XII Synthese von O.N- bzw. N.N-Acetalen der Acylisocyanate aus Amidacetalen bzw. einem Aminal-tert.-butylester und N-Halogen-carbonsäureamiden, Halogenharnstoffen und N-Chlor-urethan (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 245-255 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XII: Synthesis of Acyl Isocyanate O,N- or -N,N-Acetals from Amide Acetals or from an Aminal tert-Butylester and N-Halogencarbonamides, Halogen Ureas and N-ChlorourethanesDimethylformamide dialkylacetals (2) and aminal-tert-butylester 5 [bis(dimethylamino)-tert-butoxymethane] react with N-halogen carboxylic acid amides, halogen ureas and N-chlorourethanes to give acyl isocyanate-O,N -or -N,N-acetals (isoureas 3 or guanidines 6, respectively).
    Notes: Dimethylformamid-dialkylacetale (2) und Aminal-tert.-butylester 5 (Bis-dimethylamino-tert.-butyloxy-methan) bilden mit N-Halogen-carbonsäureamiden, Halogenharnstoffen und N-Chlor-urethan Acylisocyanat-O.N- bzw. -N.N-acetale (Isoharnstoffe 3 bzw. Guanidine 6).
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    URL: http://dx.doi.org/10.1002/cber.19701030132
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    Orthoamide, XIII Untersuchungen zum Reaktionsmechanismus der elektrophilen Substitution des Formyl-H-Atoms bei Orthoameisensäureamid-Derivaten (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 256-264 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XIII Studies on the Mechanism of Electrophilic Substitution of the Formyl-H Atom in Ortho Formic Acid AmidesOrtho formic acid amides and N-halogen carboxylic acid amides, halogen ureas or N-chloro urethanes primarily react to give adducts; these form ylides in the presence of bases. The ylides react by an intramolecular SE1- or SNi-mechanism to give O,N-acetals of the corresponding acyl isocyanates (isoureas).
    Notes: Bei der Umsetzung von Orthoamiden mit N-Halogen-carbonsäureamiden, -harnstoffen und N-Chlor-urethan wurden Primär-Addukte nachgewiesen. Diese bilden in Gegenwart von Basen Ylide, welche über einen intramolekularen SE1- oder SNi-Mechanismus C-N-Knüpfung eingehen unter Bildung von O.N-Acetalen der entsprechenden Acylisocyanate (Isoharnstoffe).
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    URL: http://dx.doi.org/10.1002/cber.19701030133
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    Borazide, X Aminoazidoborane und Alkoxyazidoborane (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 281-288 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Boron Azides, X Aminoazidoboranes and AlkoxyazidoboranesThe bis(dialkylamino)azidoboranes l a and 1b, the dialkylaminodiazidoboranes 2a and 2 b, diethylaminoazidophenylborane (3), and the dialkoxyazidoboranes 4 a and 4 b are formed from chloroboranes, chlorine being substituted by the N3-group with LiN3 or Bu3SiN3, respectively, as substitution agents. The monoazidoboranes 1, 3, and 4 are decomposed in a kinetically controlled manner at a noticeable rate only beyond 250° C; hydrolysis of the polymeric material gives the amines Et2NNH2 (from 1b), PhNH2 (from 3) and CH3ONH2 (from 4 a), respectively, indicating a rearrangement process during the thermolysis. The saltlike compounds (NH4N4 and (Et2NH2)N3, respectively, are the main products from the decomposition of the diazidoboranes 2a and 2b at 210°. The thermal decomposition of la in cyclohexene yields under participation of the solvent the diazadiborete derivative 6. From the photolytic decomposition of 1a and 1b, respectively, trisaminoboranes (as dismutation products) and the tetraaminodiazadiboretes 10 a and 10 b (as rearrangement products) are isolated.
    Notes: Die Bis(dialkylamino)azidoborane l a und l b, die Dialkylaminodiazidoborane 2 a und 2 b, Diäthylaminoazidophenylboran (3) und die Dialkoxyazidoborane 4 a und 4 b erhält man aus den entsprechenden Chlorboranen durch Azidierung mit LiN3 bzw. (im Falle von 4a) mit Bu3SiN3. Die Monoazidoborane 1, 3 und 4 zerfallen in kinetisch kontrollierbarer Weise mit nennenswerter Geschwindigkeit erst oberhalb 250°; neben N2 erhält man harzige Produkte, aus denen sich durch Verseifung die aus einer Umlagerungsreaktion hervorgegangenen Amine Ät2NNH2 (aus l b), PhNH2 (aus 3) bzw. CH3ONH2 (aus 4a) freimachen lassen. Der thermische Zerfall der Diazidoborane 2a und 2b bei 210° liefert neben N2 die salzartigen Azide (NH4)N3 bzw. (Nät2H2)N3. Der thermische Zerfall von l a in Cyclohexen führt unter Beteiligung des Lösungsmittels zum Diazadiboret-Derivat 6. Tetraaminodiazadiborete 10 a und 10 b sind neben Trisaminoboranen die Hauptprodukte des photolytischen Zerfalls von l a und l b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030136
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    Notiz über das intermediäre Auftreten von Tetrafluorbenz-in bei der Pyrolyse von SilbertetrafluorphthalatIII. Mitteil. über Reaktionen von Perfluordicarbonsäuren; II. Mitteil.: 1. c. (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 313-314 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wir berichteten vor einiger Zeit über die Pyrolyse von Silbertetrafluorphthalat (1) und äußerten die Vermutung, daß als Hauptprodukt isolierte Octafluorbiphenylen seine Bildung dem intermediären Auftreten des Tetrafluorbenz-ins verdankte. Um diese Vermutung zu bestätigen, wurde die Pyrolyse von 1 in Gegenwart eines potentiellen Benz-in-Abfängers durchgeführt. In Anlehnung an McNelis setzten wir dafür Tetraphenylcyclopentadienon (Tetracyclon) (2) ein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030141
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    Notiz zur Pyridon-Synthese von J. Thesing (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 322-324 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030145
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  • 61
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    Eine neue Methode zur Synthese von Peptiden: Aktivierung der Carboxylgruppe mit Dicyclohexylcarbodiimid unter Zusatz von 1-Hydroxy-benzotriazolen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 788-798 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Method for Synthesis of Peptides: Activation of the Carboxyl Group with Dicyclohexylcarbodiimide using 1-hydroxybenzotriazoles as Additives1-Hydroxybenzotriazole and a number of substituted 1-Hydroxybenzotriazoles are suitable additives in the synthesis of peptides using the dicyclohexylcarbodiimide method1). The glc-racemisation test described by Weygand and coworkers2) was used to determine the influence of these additives on the racemisation during peptide synthesis. The newly employed additives decrease racemisation, prohibit the formation of N-acylurea and afford peptides in excellent yield and a high state of purity.
    Notes: 1-Hydroxy-benzotriazol sowie verschiedene kernsubstituierte 1-Hydroxy-benzotriazole eignen sich als Zusätze bei der Dicyclohexylcarbodiimid-Methode zur Synthese von Peptiden. Ihr Einfluß auf die Racemisierung bei Peptidsynthesen wurde unter Anwendung des gaschromatographischen Racemisierungstests von Weygand u. Mitarbb.2) untersucht. Die neuen Zusätze senken die Racemisierung, verhindern die N-Acyl-harnstoffbildung und führen in hoher Ausbeute zu sehr reinen Peptiden.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030319
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  • 62
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    Die Stereochemie sigmatroper 1.5-Wasserstoffverschiebungen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 426-439 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Stereochemistry of Sigmatropic 1,5-Hydrogen ShiftsAt 250° (S)-cis,trans-3-methyl-7-deutero-octa-4,6-diene (5) rearranges by a non-catalysed first order reaction to a mixture of (R)-trans,cis-3-methyl-7-deutero-octa-3,5-diene (3) and (S)-cis,cis-3-methyl-7-deutero-octa-3,5-diene (4). Therefore the sigmatropic 1,5-hydrogen shift proceeds in this system preferentially by way of a suprafacial transition state, which is at least 8 kcal/mol lower in energy than the antarafacial one.
    Notes: (S)-cis,trans-3-Methyl-7-deutero-octadien-(4.6) (5) lagert sich bei 250° in einer nichtkatalysierten Reaktion erster Ordnung in ein Gemisch aus (R)-trans,cis-3-Methyl-7-deutero-octadien-(3.5) (3) und (S)-cis,cis-3-Methyl-7-deutero-octadien-(3.5) (4) um. In diesem System durchläuft die sigmatrope 1.5-Wasserstoffverschiebung damit bevorzugt einen suprafacialen Übergangszustand, der um mindestens 8 kcal/Mol gegenüber dem antarafacialen Übergangszustand begünstigt ist.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030213
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    Die katalytische Hydroaluminierung ungesättigter Verbindungen, I. Die katalytische Hydroaluminierung von Hexadien-(1.5) (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 855-862 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Catalytic Hydroalumination of 1,5-HexadieneThe hydroalumination of 1,5-hexadiene normally yields (cyclopentylmethyl)dialkylaluminium instead of the expected dimetallated hexane derivative. Titanium tetrabutoxide catalyses the reaction and favours the formation of the dimetallated product. - When the reaction is carried out in the absence of a catalyst but in the presence of electron donors such as ethers or tertiary amines, the two-fold hydroaluminated product is also formed exclusively. In such cases the reaction velocity is, however, drastically reduced. Titanium tetrabutoxide has now been found to act as an extraordinarily effective catalyst for this reaction, even in the presence of complex-forming agents. Certain amines or tetrahydrothiophene even intensify the catalytic activity of the titanium (IV) compound.
    Notes: Die Hydroaluminierung von Hexadien-(1.5) führt normalerweise nicht zu dem erwarteten dimetallierten Hexanderivat, sondern zum Cyclopentylmethyl-dialkyl-aluminium. Titantetrabutylat katalysiert die Reaktion und lenkt sie in Richtung des dimetallierten Produktes. Bei Durchführung der Reaktion ohne Katalysator, jedoch in Gegenwart von Elektronendonatoren wie Äthern oder tertiären Aminen wird ebenfalls ausschließlich das zweifach hydroaluminierte Reaktionsprodukt gebildet. Die Reaktionsgeschwindigkeit wird dabei allerdings drastisch vermindert. Titantetrabutylat katalysiert nun die Reaktion auch bei Anwesenheit der Komplexbildner außerordentlich wirksam. Durch einige tertiäre Amine oder auch durch Tetrahydrothiophen wird die katalytische Aktivität der Titan (IV)-Verbindung sogar noch verstärkt.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030327
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    Hydrazin-Reaktionen, X Untersuchungen an inversionsisomeren 1-Chlor-und 1-Amino-aziridinen Abhängigkeit der 1H-C-14N-Kopplung von der Konformation des freien Elektronenpaares (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 486-495 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrazine Reactions, X Studies on Inversion-isomeric 1-Chloro-and 1-Aminoaziridines. Dependence of the 1H-C-14N-Coupling on the Konformation of the free Electron PairThe 1H-C-14N coupling depends on the conformation of the nitrogen lone-pair electrons. In 1-chloroaziridine for protons „cis“ to the nitrogen lone-pair electrons great values were found and for „trans“ protons smaller ones. The AA' BB'-system in the n.m.r. spectrum of 1-chloroaziridine is unsymmetrical. Irradiating of 14N frequency gives decoupling of 14N from other nuclei and the spectrum becomes symmetrical. In 1-amino-2-phenylaziridine the isomer with phenyl and amino group in „trans“ position is favoured. The variation of chemical shift in benzene solution of 1-amino- and 1-chloroaziridines are discussed.
    Notes: Die 1H-C-14N-Kopplung ist von der Konformation des freien Elektronenpaares abhängig und besitzt im 1-Chlor-aziridin für zum freien Elektronenpaar„cis“-ständige Protonen große, für „trans“-ständige kleine Werte. Das AA' BB'-System des NMR-Spektrums von 1-Chloraziridin ist daher unsymmetrisch und zeigt erst beim Einstrahlen der 14N-Frequenz infolge Spinentkopplung Symmetrie. 1-Amino-2-phenyl-aziridin liegt bevorzugt als das Inversionsisomere vor, in dem Phenyl- und Aminogruppe „trans“ zueinander stehen. Die Signalverschiebungen von 1-Amino-und 1-Chlor-aziridinen in Benzol werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030218
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  • 65
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    Die Struktur des Sphaerophysins (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 534-538 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Structure of SphaerophysineSphaerophysine-formerly described as 1 or 2- is shown by n.m.r. and mass spectrometry to have structure 3 (N-(4-aminobutyl)-N-(3-methyl-2-butenyl)-guanidine). Dihydro-3 (7) has been synthesised.
    Notes: Sphaerophysin wurde bisher als 1-Isopentenylamino-4-guanidino-butan 1 oder 2 angesehen. Wir zeigen anhand von NMR- und Massenspektren sowie durch Synthese der Dihydro-verbindung, daß es die Struktur 3 eines N[4-Amino-butyl]-N-[3-methyl-buten-(2)-yl]-guanidins hat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030223
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    Heterosubstituierte Acetylene, XXV C2-Kettenverlängerung von Aldehyden und Ketonen mit Inaminen: Die Synthese substituierter Acrylamide (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 564-572 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Acetylenes, XXV Chain-Extension of Aldehydes and Ketones by two Carbon Atoms with Ynamines: Synthesis of Substituted AcrylamidesThe addition of ynamines to carbonyl groups, especially of aldehydes and ketones, leads to derivatives of acrylamides by reduction of which with lithiumaluminiumhydride and hydrogenation amines are available. The stereochemistry of the condensation has been investigated. cis- acrylamides are stereospecifically obtained by a kinetically controlled reaction from aldehydes.
    Notes: Die Addition von Inaminen an Carbonylverbindungen, insbesondere Aldehyde und Ketone. Führt zu Acrylamidderivaten, aus denen mit Lithiumaluminiumhydrid und durch Hydrierung Amine erhältlich sind. Die Stereochemie der Addition wurde untersucht: Aus Aldehyden entsteht kinetisch gesteuert und stereospezifisch das cis-Acrylamid.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030227
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    Modellversuche zur oxydativen Phosphorylierung, XIII Notiz über Hämin als Oxydationsmittel bei der Synthese von Adenosintriphosphat mittels Tocopherol oder Thioglykolsäure (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 648-651 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030238
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  • 68
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    Polycyclische Kohlenwasserstoffe durch Cycli-Alkylierung, IV. Cycli-Alkylierungen von Benzol und teilhydrierten mehrkernigen Aromaten mit 1.2-Bis-brommethyl-cyclohexan (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 659-662 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycyclic Hydrocarbons by Cycli-alkylation, IV. Cycli-alkylations of Benzene and Partially Hydrogenated Polycyclic Aromatic Hydrocarbons with 1.2-Bis(bromomethyl)cyclohexaneThe reactions of benzene and partially hydrogenated aromatic hydrocarbons such as tetrahydronaphthalene and symm. octahydrophenanthrene with a mixture of cis- and trans 1.2-Bis (bromomethyl)cyclohexane in the presence of aluminiumchloride lead to the partially hydrogenated polycyclic hydrocarbons 2-6; the dehydrogenation with Pd/C yields the corresponding aromatic compounds.
    Notes: Die Reaktionen von Benzol and teilhydrierten Aromaten, wie Tetrahydronaphthalin und symm. Octahydrophenanthren, mit einem Gemisch aus cis- und trans-1.2-Bis-brommethyl-cyclohexan in Gegenwart von Aluminiumchlorid führen zu den partiell hydrierten polycyclischen Kohlenwasserstoffen 2-6, deren Dehydrierung mit Pd/C die entsprechenden Aromaten ergibt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030302
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    Reaktionen mit Phosphinalkylenen, XXV. Eine neue Synthese von α.β-ungesättigten Carbonsäuren (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 685-693 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Alkylidenetriphenylphosphoranes, XXV. A New Synthesis of α.β-Unsaturated Carboxylic AcidsThe reaction between alkylidenetriphenylphosphoranes (1) and α-bromo-or α-iodocarboxylic esters (2) (ratio 2:1) gives rise to the formation of α,β-unsaturated carboxylic esters (4), triphenylphosphine and phosphonium salts. The mechanism and the sterochemistry of this reaction are discussed.
    Notes: Triphenylphosphinalkylene (1) reagieren mit α-Brom-oder α-Jod-carbonsäureestern (2) im Molverhältnis 2:1 zu α.β-ungesättigten Carbonsäureestern (4), Triphenylphosphin und Phosphoniumsalzen. Der Mechanismus und die Stereochemie dieser Reaktion werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030306
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    Umlagerungsreaktionen, V. Eine kinetische Studie zum Mechanismus der Wolff-Umlagerung (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1463-1476 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement Reactions, V. A Kinetic Study on the Mechanism of the Wolff-RearrangementFor the thermal Wolff-rearrangement in the presence of nucleophiles such as alcohols or amines, the nitrogen evolution is measured as a function of the nucleophile concentration. With triphenylacetyldiazomethane and diacyldiazomethanes no influence of benzyl alcohol or aniline on the decomposition constants was found, whereas with phenylbenzoyldiazomethane, 2-oxo-1-diazocyclohexane and -dodecane a linear increase with the nucleophile concentration is observed. Benzyl alcohol, aniline and N-methylaniline are more active than pyridine, benzylamine or polar compounds such as nitrobenzene or bromobenzene. This acceleration is evidently a consequence of proton activity of the nucleophiles and not of an addition according to 2 → 3. The same effect is also observed with diazo compounds which cannot undergo the Wolff-rearrangement.
    Notes: Für die thermische Wolff-Umlagerung in Gegenwart von Nucleophilen (Alkohole, Amine) wird die Geschwindigkeit der Stickstoffentwicklung in Abhängigkeit von der Nucleophil-Konzentration gemessen. Bei Triphenylacetyl-diazomethan (7) sowie Diacyl-diazomethanen wird kein Einfluß von Benzylalkohol oder Anilin auf die Zersetzungskonstanten beobachtet, bei Phenyl-benzoyl-diazomethan, 2-Oxo-1-diazo-cyclohexan und -dodecan dagegen ein linearer Anstieg mit der Nucleophil-Konzentration. Benzylalkohol, Anilin und N-Methyl-anilin sind wirksamer als Pyridin, Benzylamin oder rein polare Zusätze wie Nitro- und Brombenzol. Diese Beschleunigung ist offenbar eine Folge der Protonaktivität der Nucleophile und nicht einer Einlagerung gemäß 2 → 3. Sie tritt auch bei Diazoverbindungen auf, die zur Wolff-Umlagerung nicht befähigt sind.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030518
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    Synthetische Arbeiten in der Reihe der aromatischen Erythrina-Alkaloide, XIII. Ein direkter Weg zum 15.16-Dimethoxy-cis-erythrinan-dion-(1.8) (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1512-1521 
    Details
    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, XIII. A Direct Course to cis-15,16-Dimethoxyerythrinane-1,8-dioneThe enollactam 5 is obtained from ethyl dihydroresorcinol-2-acetate via the diketalamide 16. Cyclisation by heating with phosphoric acid yields the ketolactam 6; the overall yield of the five steps synthesis is 20%.
    Notes: Aus Dihydroresorcin-2-essigester wird über das Diketalamid 16 die Cyclisierungsvorstufe 5 gewonnen. Sie liefert beim Erhitzen mit Phosphorsäure das Ketolactam 6 mit einer Ausbeute von 20% über 5 Stufen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030522
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    Arylidenisophorone Darstellung und Eigenschaften eines halochromen Polymethinsystems (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1168-1173 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arylidene Isophorones Preparation and Properties of a Halochromic Polymethine SystemIsophorone (1) and araldehydes condense to give aryliden-isophorones 2-19. The yellow ary-dien-one systems of 2-19 form red polymethine cations like 21. Compounds of vinylogous carbonic acid structure yield red polymethine anions like 22. Differences between cation and anion are spectroscopically small with 6 relative to benzaurin (20).
    Notes: Aus Isophoron (1) und Araldehyden erhält man die Arylidenisophorone 2-19. Das gelbe Aryl-dien-on-System in 2-19 addiert leicht Protonen zu roten Polymethin-Kationen wie 21; vinyloge Carbonsäuren wie 6 bilden durch Dissoziation rote Polymethin-Anionen (22).Kation und Anion von z. B. 6 sind einander spektroskopisch ähnlicher als die analogen Salze des Benzaurins (20).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030419
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    Heterosubstituierte Acetylene, XXX. Ein neuer Mechanismus der nucleophilen Halogensubstitution an Acetylendreifachbindungen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1216-1224 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Acetylenes, XXX1). A new Mechanism of Nucleophilic Halogen Substitution at Acetylene Triple BondsThe combination of nucleophilic and directiospecific addition in β-position to halogen 1) (except fluorine) with subsequent onium rearrangement is proposed as a new mechanism of nucleophilic halogen substitution at the acetylene triple bond. The reactions of chloro-tertbutyl-acetylene (1) with phenolate and thiophenolate are described as examples. The β-adducts 2,5 und 6 are formed directiospecifically. 5 and 6 give rise photochemically and thermally to the thermodynamically more stable isomer 8 in which the chlorine atom and the thioether residue have migrated and changed their C-atoms. All thioether isomers produce the tert-butylethinyl-thioether 10 upon elimination of HCl.
    Notes: Die Kombination von nucleophiler directiospezifischer Addition in β-Stellung zum Halogen1) (außer Fluor) mit anschließender Onium-Umlagerung 2) und Halogen-Anion-α-Eliminierung wird als neuer Mechanismus der nucleophilen Halogensubstitution an der Acetylendreifachbindung vorgeschlagen. Als Beispiel für diese Reaktionsschritte werden die Umsetzungen von Chlor-tert.-butyl-acetylen (1) mit Phenolat und mit Thiophenolat beschrieben. Directiospezifisch entstehen die β-Addukte 2,5 und 6. Thermisch und photochemisch bildet sich aus 5 und 6 das thermodynamisch stabilere Isomere 8, in welchem Chlor und der Thioätherrest unter Vertauschung der C-Atome gewandert sind. Alle Thioäther-Isomeren liefern bei der HCl-Abspaltung den tert.-Butyläthiny-thioäther 10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030425
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    Übergangsmetall-Carben-Komplexe, XIX. Zur Synthese von Cyclopropanderivaten mit Übergangsmetall-Carbonyl-Carben-Komplexen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1273-1278 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbene Complexes, XIX. Synthesis of Cyclopropane Derivatives with Transition Metal Carbonyl Carbene ComplexesPhenyllmethoxycarbenepentacarbonylchromium(0) (1b) reacts on warming with trans-methyl crotonate (2) stereospecifically to give the isomeric methyl 2-methoxy-3-methyl-2-phenycyclopropane-1-carboxylates (3a, b) via transfer of the carbene ligand. The configuration of the isomers was determined by analysis of the 1H n.m.r. spectra.
    Notes: Phenylmethoxycarben-pentacarbonyl-chrom(0) (1b) reagiert bei erhöhter Temperatur unter Übertragung des Carbenrestes mit trans- Crotonsäure-methylester (2) stereospezifisch zu den isomeren 2-Methoxy-3-methyl-2-phenyl-cyclopropan-carbonsäure-(1)-methylestern (3a, b). Die Konfiguration der Isomeren wurde durch Analyse der 1H-NMR-Spektren bestimmt.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030430
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    Berichtigung (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1306-1306 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030435
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    Masthead (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030501
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    Photochemie Kleiner Ringe, 19. Photolyse von Spiro-pyrazolen zu Cyclopropabenzolen und ihre Reaktionen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1334-1346 
    Details
    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, 19. Photolysis of Spiro-pyrazoles to Cyclopropabenzenes and their ReactionsPhotolysis of cyclopentadiene-spiro-pyrazoles (9) in benzene yields 1 H-cyclopropabenzenes (10) in a novel reaction. The latter compounds can be rearranged thermally to benzofuranes (11). Degradation reactions of diphenylcyclopropabenzene 10c to give 2′-p-terphenylylacetic acid (14c) together with the spectroscopic data prove the structure of the cyclopropabenzenes.  -  The formation of 10 from 9 involves n→π*-excitation, followed by ring enlargement to indazoles (24) which eliminate nitrogen in a familiar manner. The excited states of 9 and 24 are triplets.
    Notes: Die Photolyse von Cyclopentadien-spiro-pyrazolen (9) in Benzol liefert in einer neuartigen Reaktion 1 H-Cyclopropabenzole (10). Diese können thermisch in Benzofurane (11) umgelagert werden. Abbaureaktionen des Diphenyl-cyclopropabenzols 10c zu p-Terphenylyl-(2′)-essigsäure (14c) zusammen mit den spektroskopischen Daten beweisen die Struktur der Bicyclen 10.  -  Die Bildung von 10 aus 9 verläuft über eine n→π*-Anregung, gefolgt von einer Ringerweiterung zu Indazolen (24), die in bekannter Weise Stickstoff eliminieren. Die Anregungszustände von 9 und 24 sind Tripletts.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030505
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    Abfangreaktionen Kurzlebiger Radikale, VII. Zum stereochemischen Verlauf radikalischer Additionen an konjugierte Diene: Hydrostannierung und Isomerisierung von Pentadien-(1.3) (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1372-1382 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Short-Life Radicals, VII. The Stereochemical Route of Free-Radical Additions to Conjugated Dienes: Hydrostannation and Isomerization of Penta-1,3-dieneThe radical addition of Me3SnH and Et3SnH to both of the pure stereoisomers of penta-1,3-diene proceeds by a highly stereospecific mechanism, whereby an extremely high configurational stability of the intermediate allyl radicals 9 is indicated. Besides 1,2- and 1,4-adducts small amounts of 4,1-adducts are formed: altogether 6 of the 8 possible isomers 1-8 are obtained. At 80° the cis-diene reacts 2.6 or 2.9 times faster than the trans-isomer. At 20° and 40° only the transoid conformation is involved in the reaction of cis-isomer, whereas in the case of the trans-diene both cisoid and transoid configurations are involved. The attack of organotin radicals at C-4 (that is, at the internal C=C double bond) is much more readily reversible than that at C-l and leads (primarily) to cis-trans-isomerization of the diene; this is highly dependent on the molar ratio of diene to hydride. By means of capillary gas chromatography it was possible to observe each stage of the addition and isomerization processes.
    Notes: Die beiden Stereoisomeren von Pentadien-(1.3) addieren (CH3)3SnH und (C2H5)3SnH radikalisch hochgradig stereospezifisch, woraus eine beträchtliche Konfigurationsstabilität der intermediär auftretenden Allylradikale 9 folgt. Neben 1.2- und 1.4- entstehen wenig 4.1-Addukte, insgesamt 6 der 8 möglichen Isomeren 1-8. Das cis-Dien reagiert bei 80° 2.6 bzw. 2.9 mal schneller als das trans-Isomere. Bei 20° und 40° ist nur die transoide Konformation des cis-Isomeren beteiligt, beim trans-Dien dagegen sowohl cisoide als auch transoide. Der Angriff von Stannylradikalen an C-4, also an der mittelständigen C=C-Gruppe, ist weit stärker reversibel als derjenige am endständigen C-l und bedingt so (hauptsächlich) eine cis-trans-Isomerisierung des Diens. Diese hängt stark vom Molverhältnis Dien : Hydrid ab. Mittels Kapillar-GC konnten Additionen und Isomerisierung in jedem Stadium verfolgt werden.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030509
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    Nachweis und Darstellung metallierter Nitroaromaten (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1412-1419 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Identification and Preparation of Metalated NitroarenesPhenyllithium is unable to metalate nitrobenzene in THF, but instead is oxidized quantitatively to phenol at low temperatures. With 2-bromo-1-nitrobenzene and its methyl homologues a bromo-lithium exchange is effected to give high yields of the deeply coloured title compounds. They are stable only below -100° and are trapped as carboxylic acids with carbon dioxide. The halogen-metal exchange competes with the reduction of the nitro group, the latter reaction being favoured at higher temperatures and in solvents of low polarity. The redox reactions at the nitro group predominate with 3-and 4-bromo-1-nitrobenzene even under optimum conditions.
    Notes: Nitrobenzol wird durch Lithiumorganyle nicht metalliert. Dagegen oxydiert es Phenyllithium in Tetrahydrofuran(THF) schon bei tiefer Temperatur quantitativ zu Phenol. Der Brom-Lithium-Austausch an 2-Brom-1-intro-benzol und seinen Methylhomologen führt in hohen Ausbeuten zu den unterhalb von -100° stabilen, tieffarbigen Titelverbindungen, die man durch Carboxylierung nachweist. Die mit dem Halogen-Metall-Austausch konkurrierende Reduktion der Nitrogruppe tritt bei höherer Temperatur und in weniger polaren Lösungsmitteln stärker hervor; sie überwiegt bei 3- und 4-Brom-1-nitro-benzol auch unter optimalen Bedingungen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030513
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    Untersuchungen an Diazoverbindungen, VII. Vergleichende kinetische Untersuchungen zur thermischen Stabilität aliphatischer Diazoverbindungen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1477-1485 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Diazo Compounds, VII. Comparative Kinetic Investigations on the Thermal Stability of Aliphatic Diazo CompoundsThe thermal stabilities of 16 aryl-, carbonyl-, sulfonyl-, phosphinyl- and phosphono-substituted diazomethanes are compared. From kinetic measurements on the decomposition of the diazo compounds in mesitylene the comparison values τ100, T 0.1 and k100 as well as the activation energy Ea of the N2-elimination were determined (see table 1). The following series of substituents with increasing stabilizing effect was derived:C6H5 〈 C6H5CO 〈 CH3CO 〈 Aryl-SO2 〈 (C6H5)2PO 〈 C2H5OCO 〈 (C2H5O)2PO 〈 H Carbonyl diazo compounds are thermally less stable than their PO-analogs (see figure 1), because of the mesomerism C ↔ D resulting from the interaction of the CO- and CN2-groups.
    Notes: Die thermischen Stabilitäten von 16 aryl-, carbonyl-, sulfonyl-, phosphinyl- und phosphono-substituierten Diazomethanen werden verglichen. Aus der Zersetzungskinetik in Mesitylen werden die Vergleichsgrößen τ100, T0.1 bzw. k100 sowie die Aktivierungsenergie Ea der N2-Abspaltung bestimmt. (s. Tab. 1). Eine Stabilisierungsreihe für die folgenden Substituenten wird abgeleitet: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm C}_{\rm 6} {\rm h}_{\rm 5} {\rm 〈 C}_{\rm 6} {\rm H}_{\rm 5}{\rm CO 〈 CH}_{\rm 3} {\rm CO 〈 Aryl - SO}_{\rm 2} {\rm 〈 (C}_{\rm 6} {\rm H}_{\rm 5} {\rm)}_{\rm 2} {\rm PO 〈 C}_{\rm 2} {\rm H}_{\rm 5} {\rm OCO 〈 (C}_{\rm 2} {\rm H}_{\rm 5} {\rm O)}_{\rm 2} {\rm PO 〈 H} $$\end{document}Carbonyl-diazoverbindungen sind thermisch instabiler als ihre PO-Analogen (s. Abbild.), bedingt durch mesomere Wechselwirkungen zwischen CO- und CN2-Gruppe gemäß C↔D.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030519
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    Synthetische Arbeiten in der Reihe der aromatischen Erythrina-Alkaloide, XIV. Übertragung der Glyoxylester-Synthese auf Dihydroresorcin (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1522-1535 
    Details
    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, XIV. Application of the Glyoxylester Synthesis to DihydroresorcinolThe monocycloketal 7 of dihydroresorcinol yields, via glyoxylester synthesis, the condensation product 10. On treatment with dilute phosphoric acid, 10 hydrolyses to give the partially hydrogenated ketoisatin derivative 14a which is stabilised by conjugation and cannot be cyclised. In the presence of crystalline phosphoric acid 10 forms a violet cation, Pictet-Spengler cyclisation of which leads to a mixture of stereoisomeric spiroisoquinolines (22). From the mixture two racemates are isolated, the n. m. r. analysis of which permits the assignment of cis- and trans-configurations according to the formulae 22A and 22B.
    Notes: Aus dem Monocycloketal 7 des Dihydroresorcins wird auf dem Weg der Glyoxylestersynthese die Cyclisierungsvorstufe 10 gewonnen. Sie hydrolysiert unter der Einwirkung von verdünnter phosphorsäure zu dem Partiell hydrierten Ketoisatin-Derivat 14a, das durch Konjugation stabilisiert und nicht cyclisierbar ist. Mit kristalliner Phosphorsäure entsteht aus 10 ein violettes Kation, das durch Ringschluß nach Pictet-Spengler zu einem Gemisch stereoisomerer Spiroisochinoline 22 abreagiert. Nach Auftrennung in zwei Racemate wird durch NMR-Analyse die sterische Zuordnung zur cis- und trans-Reihe entsprechend den Formulierungen 22A und 22B ermittelt.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19701030523
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    Zur Darstellung von Bioxazolylen-(2.2′) und Bithiazolylen-(2.2′) sowie von Arylen-bis -oxazolyl-(2)- und Arylen-bis-thiazolyl-(2)-Derivaten (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1572-1577 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of 2,2′-Bisoxazolyls and 2,2′ -Bisthiazolyls, of Arylene-bis-2-oxazolyl and Arylenebis-2-thiazolyl DerivativesThe reaction of desylamine hydrochloride with carboxylic acid chlorides and dicarboxylic acid chlorides yields ms- (acylamino) desoxybezoins (2a, b) and amides of N, N′ -bis-desyldicarboxylic acids (2c,-f), respectively. These compounds are converted by condensation with phosphorus pentachloride to derivatives of oxazole (3) and by condensation with phosphorus pentasulfide to derivatives of thaizole(4).
    Notes: Durch Umsetzung von Desylaminhydrochlorid mit Carbonsäurechloriden bzw. mit Dicarbonsäuredichloriden gelangt man zu ms-Acyalmino -desoxybenzoinen (2a, b) bzw. zu N. N′-Bis-desyl- dicarbonsäurediamiden (2c-f). Diese lassen sich mit Phosphorpentachlorid zu Oxazolderivaten 3, mit Phosphorpentasulfid zu Thiazolderivaten 4 kondensieren.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030527
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    Monosaccharide mit stickstoffhaltigem Ring, XXXVIII. Darstellung und Dimerisierung von 5-Benzylamino-1.2.-O-isopro-pyliden-5-desoxy-L-ido-hexodialdo-1.4(β)-3.6(α, β)-difuranose (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1631-1636 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monosaccharides Containing Nitrogen in the Ring, XXVIII. Synthesis and Dimerization of 5-Benzylamino-1,2-O-isopropylidene-5-deoxy-L-ido-hexodialdo-1,4(β)-3,6(α,β)-difuranoseSelective hemihydrogenation of 5-benzylamino-1,2-O-isopropylidene-5-deoxy-β-L-idofuranuronic acid nitrile (1) yields 5-benzylamino-1,2-O-isopropylidene-5-deoxy-L-ido-hexodialdo-1,4(β)-3,6(α,β)-difuranose (2), which can be dimerized to 5. 5 represents a symmetrical heptacyclic system of five- and six-membered rings containing a central piperazine ring.
    Notes: Selektive Halbhydrierung des 5-Benzylamino-1.2-O-isopropyliden-5-desoxy-β-L-idofuranuron-säurenitrils (1) liefert 5-Benzylamino-1.2-O-isopropyliden-5-desoxy-L-ido-hexodialdo-1.4(β)-3.6(α, β)-difuranose (2), die zu 5 dimerisiert werden kann. In 5 liegt ein symmetrisches heptacyclisches Ringsystem mit zentralem Piperazinring vor.
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    URL: http://dx.doi.org/10.1002/cber.19701030533
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    Monosaccharide mit stickstoffhaltigem Ring, XXVII. Pyrolytische Umlagerung von 4-Amino-4-desoxy-L-xylose in 4-Amino-4-desoxy-L-lyxose (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1621-1630 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monosaccharides Containing Nitrogen in the Ring, XXVII. Pyrolytic Rearrangement of 4-Amino-4-deoxy-L-xylose to 4-Amino-4-deoxy-L-lyxosePyrolysis of the periodate degradation product 2 results in the rearrangement of the L-xylo-to the L-lyxo-configuration and the formation of 4-amino-4-N, 5-O-carbonyl-2,3-O-isopropy-liden-4-deoxy-α-L-lyxofuranose (5). Free 4-amino-4-deoxy-L-lyxose is formed from 5 via the bisulfite adduct 13, which exists as an equilibrium mixture of the pyrrolidine-forms 14 ⇋ 15 ⇋ 18 The bis-pyrrolidine-form 18 predominates under anhydrous conditions. The dimeric structure of 18 is established by mass spectra of the pentaacetate 16 and the TMS-ether 17.
    Notes: Durch Pyrolyse des Perjodat-Spaltproduktes 2 erfolgt Umlagerung der L-xylo-in die L-lyxo-Konfiguration, und es wird 4-Amino-4-N.5-O-carbonyl-2.3-O-isopropyliden-4-desoxy-α-L-lyxofuranose (5) erhalten. Aus 5 ist über das Schwefligsäure-Addukt 13 freie 4-Amino-4-desoxy-L-lyxose darstellbar, die im Gleichgewicht der Pyrrolidin-Formen 14 ⇋ 15 ⇋ 18 vorliegt. Die Bis-Pyrrolidin-Form 18 überwiegt stark in der wasserfreien Substanz. Die dimere Struktur von 18 ergibt sich aus den Massenspektren des Pentaacetats 16 und des TMS-Äthers 17.
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    URL: http://dx.doi.org/10.1002/cber.19701030532
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    Masthead (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030601
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    Reaktionen an N-Halogenphosphoranyliden-thiophosphoryldihalogenidamiden (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1664-1673 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with N-Halogenphosphoranyliden-thiophosphoryldihalogenide AmidesThe reaction of S=PX2N=PF3 (X=F, Cl) with Si—N-compounds afforded the new compounds 1-11. It was proved that substitutions occurred only at the -N=PF3 group and that isomeric compounds were not formed. The reaction of S=PCl2N=PF3 and S=PFClN=PF3 with excess PF3Cl2 resulted in the formation of S=PCl2N=PFCl2 (12). The compounds 1, 2 are cleaved with water-free HBr at the P—N-bond to form the compounds 13, 14. The reaction of SPF2N=PF3 with amines yielded various products. The compounds 1-12 are much more stable towards hydrolysis than the starting compounds. 1H-, 19F-n.m.r., i.r., and mass spectra are reported and partially discussed.
    Notes: Durch Umsetzung von S=PX2N=PF3 (X=F, Cl) mit Si-N-Verbindungen erhielten wir die neuen Verbindungen 1-11. Wir konnten wahrscheinlich machen, daß die Substitutionen an der - N = PF3-Gruppe erfolgen und daß die isomeren Verbindungen dabei nicht ent-stehen. Die Reaktion von S=PCl2N=PF3 oder S=PFClN = PF3 mit überschüssigem PF3Cl2 führt zu S=PCl2N=PFCl2 (12). Die Verbindungen 1, 2 lassen sich mit wasserfreiem HBr an der P —N-Bindung spalten, wobei die Verbindungen 13, 14 entstehen. Die Umsetzung von S=PF2N=PF3 mit Aminen ergibt verschiedene Produkte. Die Verbindungen 1-12 sind gegen Hydrolyse stabiler als die Ausgangsverbindungen. 1H-, 19F-NMR-, IR- und Massenspektren werden mitgeteilt und teilweise diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030603
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    Glykoside von Aminozuckern, II. Zur Synthese von 2-Amino-2-desoxy-α-D-glucopyranosiden (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1792-1796 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosides of Amino Sugars, II. Synthesis of 2-amino-2-deoxy-α-D-glucopyranosidesThe synthesis of glycosides and disaccharides of 2-amino-2-deoxy-D-glucose has been explored using trifluoroacetyl as the N-blocking group. Because of its high tendency for neighboring group participation only β-D-glycosides were formed. The corresponding α-disaccharide could be obtained as the main product when employing 2.4-dinitrophenyl as the N-protecting group.
    Notes: Die N-Trifluoracetyl-Schutzgruppe wurde zur Synthese von Glykosiden und Disacchariden der 2-Amino-2-desoxy-D-glucose benutzt. Sie zeigte eine hohe Tendenz zur Nachbargruppen-beteiligung unter Bildung von -β-D-Glykosiden. Das entsprechende α-Disaccharid wurde als Hauptprodukt bei Verwendung der N-2.4-Dinitrophenyl-Schutzgruppe erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030614
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    Isolierung, Struktur und Synthese von 5.6.7.4′-Tetrahydroxy-3′-methoxy-flavon (Batatifolin), einem neuen Flavon aus Mikania batatifolia D.C. (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1822-1827 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isolation, Structure, and Synthesis of 5,6,7,4′-Tetrahydroxy-3′-methoxyflavone (Batatifoline), a new Flavone from Mikania batatifolia D.C.The flavone batatifoline has been isolated from Mikania batatifolia D. C. (Compositae). Its structure has been confirmed as 5,6,7,4′-tetrahydroxy-3′-methoxyflavone (1) by synthesis of the isomers 1 and 5,6,3′,4′-tetrahydroxy-7-methoxyflavone (5, Pedalitine).
    Notes: Aus Mikania batatifolia D. C. (Compositae) wurde das Flavon Batatifolin isoliert und ihm durch Synthese der Isomeren 5.6.7.4′-Tetrahydroxy-3′-methoxy-flavon (1) und 5.6.3′.4′-Tetra-hydroxy-7-methoxy-flavon (5, Pedalitin) die Struktur 1 zugeordnet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030618
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    Polyacetylenverbindungen, 175. Synthese und Biogenese von Anthemis-Thioäthern (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1886-1893 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyacetylenic Compounds, 175. Synthesis and Biogenesis of Anthemis-thioethersThe configurations of four isomeric naturally occuring thioethers are established by synthesis and a detailed analysis of the n. m. r. spectra. By feeding of 3H-labelled 1-4 the biogenesis of a phenylthioether is further confirmed.
    Notes: Die Konfigurationen von vier natürlich vorkommenden Thioäthern werden durch Synthese und eine eingehende Analyse der NMR-Spektren sichergestellt. Durch Verfütterung von 3H-markierten 1-4 wird die Biogenese eines Phenylderivates weiter gesichert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030627
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  • 90
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    Racemisierung bei Peptidsynthesen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2024-2033 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Racemization in Peptide SynthesesVarious gaschromatographic racemization tests indicate, that 3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine as additive to DCCD decreases racemization in the DCCD-method to a minimum, compared with a series of N-hydroxy-compounds. It is also possible to prepare the intermediate activated esters without racemization. Addition of weak tertiary bases has a favourable effect on the yield and racemization in the preparation of N-acylpeptide-N-hydroxysuccinimide esters by the DCCD-method.
    Notes: Durch Anwendung mehrerer gaschromatographischer Racemisierungstests wurde gefunden, daß bei der DCCD-Methode1) aus einer Reihe von N-Hydroxyverbindungen als Zusatz zum DCCD das 3-Hydroxy-4-oxo-3.4-dihydro-1.2.3-benzotriazin die Racemisierung am wirkungsvollsten senkt. Auch eine racemisierungsfreie Voraktivierung ist mit dieser Verbindung möglich. Bei der Herstellung von N-Acyl-peptid-[N-hydroxy-succinimidestern] nach der DCCD-Methode wirkt sich ein Zusatz schwacher tert. Basen günstig auf Ausbeute und Racemisierung aus.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030704
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  • 91
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    Ionen, II. Wittig-Olefinierung mit Phosphoniumfluoriden (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2077-2083 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ions, II. Wittig Olefination with Phosphonium FluoridesPhosphonium fluorides are available by ion exchange and can be used for the Wittig reaction without an auxiliary base.
    Notes: Phosphoniumfluoride sind durch Ionenaustausch zugänglich und gehen ohne Hilfsbase die Wittig-Reaktion ein.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030709
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  • 92
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    Phosphororganische Verbindungen, 65. Die selektive Abspaltung von Allylgruppen aus Allylphosphonium-, -arsonium- und -sulfoniumsalzen und aus Allylsulfonen durch „Cyanolys“ (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2718-2728 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Phosphorus Compounds, 65. The Selective Elimination of Allyl Groups from Allylphosphonium, -arsonium and -sulfonium Salts and from Allyl sulfones by CyanolysisKCN cleaves allylphosphonium, -arsonium, and -sulfonium salts to give methacrylonitrile and tertiary phosphines, tertiary arsines or thioethers, respectively. Phosphonium and arsonium salts with four different ligands can be built up by alternate cyanolysis and quaternization. Allylammonium salts do not undergo the reaction, nor do allylphosphine oxides and dialkyl allylphosphonates. On the other hand, ally sulfones react with KCN to afford good yields of methacrylonitrile and sulfinic acids.
    Notes: KCN spaltet Allylphosphonium-, -arsonium- und -sulfoniumsalze in Methacrylnitril und tertiäre Phosphine, tertiäre Arsine und Thioäther auf. Durch alternierende Cyanolyse und Quartärisierung können Phosphonium- und Arsoniumsalze mit vier verschiedenen Liganden aufgebaut werden. Allylammoniumsalze, Allylphosphinoxide und -phosphonsäureester können nicht gespalten werden. Dagegen liefern Allylsulfone mit KCN in guten Ausbeuten Methacrylnitril und Sulfinsäuren.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030903
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  • 93
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    Stereochemie und Solvolyse einiger 3.4-disubstituierter Chromane (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2768-2774 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry and Solvolysis of some 3,4-Disubstituted ChromansReduction of 3-bromachromanone-(4) and of 3-bromo-2,6- dimethylchromanone-(4) yields the cis-3-bromo-4- hydroxychromans 1 and 2 which we converted to the trans-3,4-dihalogenochromans 8-11. Hydrolysis of 8-11 produces the trans-3-bromo-4-hydroxychromans 3 and 4; Solvolysis with alkohols yields the trans -3-bromo-4-alkoxychromans 5-7; by reaction with phenol we got the 3-bromo-4-arylchroman 12.
    Notes: Reduktion von 3-Brom-chromanon-(4) und 3-Brom-2.6 - dimethyl-chromanon-(4) liefert die 3c-Brom-4r -hydroxy-chromane 1 und 2, welche in die 3t.4r-Dihalogen-chromane 8-11 umgewandelt wurden. Die Hydrolyse von 8-11 ergibt die 3t-Brom- 4r-hydroxy-chromane 3 und 4; die Solvolyse mit Alkoholen führt zu den 3t- Brom-4r-alkoxy-chromanen 5-7; bei der Umsetzung mit Phenol haben wir dagegen das 3-Brom-4-aryl-chroman 12 erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030908
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  • 94
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    Rotationsbehinderung um die Arsen- und Antimon-Stickstoff-Bindung (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2784-2793 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hindered Rotation about the Arsenic and Antimony Nitrogen BondProton n. m. r. of aminoarsines and aminostibines of the type [(CH3)3C]2El-N[M(CH3)3]2 (El = As, Sb; M = Si, Ge) has been measured as a function of temperature. At 35° 4a, 4d, and 6c possess gauche-configuration with hindered rotation about the El—N bond. The corresponding ΔG≠ -values are 〉 23.2 kcal/Mol for 4a, 22.8 kcal/Mol for 4d and 19.6 kcal/ Mol for 6c. Comparison of 4a, 4d, and 6c with 6a, 6b, 7, and 8 supports the hypothesis that steric interactions and not (p→d)π-bonds between the El-N bond cause this hindered rotation. The proton n. m. r. spectra of 4b, 4c, 4e, and 5 give evidence that in the case of 4b, 4c, and 4e rotamers with different population are formed at 35°, whereas in the case of 5 only one rotamer is formed at 35°.
    Notes: Temperaturabhängige 1 H-NMR-Untersuchungen an Aminoarsinen und Aminostibinen des Typs [(CH3)3C]2El-N[M(CH3)3]2(El = As, Sb; M = Si, Ge) zeigen, daß 4a, 4d und 6c bei 35° in der gauche-Form mit rotationsgehinderter El-N-Bindung vorliegen. Die entsprechenden ΔG≠-Werte betragen für 4a 〉 23.2 kcal/Mol, für 4d 22.8 kcal/Mol und für 6c 19.6 kcal/Mol. Die Hypothese, daß diese Rotationsbehinderung auf sterische und nicht auf (p→d)π-Wechselwirkung zurückzuführen ist, wird durch die Vergleichssubstanzen 6a, 6b, 7 und 8 erhärtet. Für 4b, 4c, 4e und 5 geben die 1H-NMR-Spektren einen Hinweis darauf, daß 4b, 4c und 4e bei 35° Rotamere unterschiedlicher Population, 5 ausschließlich ein Rotameres bildet.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030911
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  • 95
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    Substituierte Rheniumcarbonylchloride mit sauerstoffhaltigen Liganden (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2836-2844 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substituted Rheniumcarbonyl Chlorides with Ligands Containing OxygenPolymeric [Re(CO)3Cl]x is extremely reactive even toward very weak ligands containing oxygen. Thus monomeric and dimeric compounds have been obtained with aliphatic alcohols. The resulting complexes contain sp3-hybridized oxygen-metal bonds. Compounds of the same type are also form ed with ethers such as diisopropylether and dioxane. With monodentate ketones predominantly complexes of the dimeric type [Re(CO)3LKetCl]2 have been obtained. Only with acetone has a monomeric compound Re(CO)3L2Cl been isolated. 1,2- and 1,3- diketones generally act as bidentate ligands yielding stable 5- or 6-membered ring complexes, which, however, are not innercomplexes, as they contain only Re-O-π-bonds. -The Structure of the compounds has been elucidated by i. r. and mass spectra as well as by molecular weight measurements.
    Notes: Polymeres [Re(CO)3Cl]x ist selbst gegenüber sehr schwachen sauerstoffhaltigen Liganden äußerst reaktiv. So wurden mit aliphatischen Alkoholen ein- und zweikernige Verbindungen, z. B. Re(CO)3L′AlCl (L′Al = HOC2H4OH) bzw. [Re(CO)3LAlCl]2 (LAl = i-C3H7OH, i-C4H9OH), erhalten. Die Bindung erfolgt über sp3-hybridisierten Sauerstoff an das Metall. Komplexe des gleichen Typs entstehen auch mit äthern, wie Diisopropyläther und Dioxan. Mit monofunktionellen Ketonen wurden vorwiegend Komplexe vom zweikernigen Typ [Re(CO)3LKetCl]2 mit „ylid“-artiger Bindung der Liganden an das Metallatom gebildet. Lediglich mit Aceton wurde eine einkernige Verbindung Re(CO)3L2Cl isoliert. 1.2- und 1.3- Diketone fungieren im allgemeinen als zweizählige Liganden unter Ausbildung stabiler Fünf-bzw. Sechsring-Chelatkomplexe, die jedoch nicht Innerkomplexe sind, d. h. nur Re-O-π-Bindungen enthalten. -Die Struktur der Verbindungen wurde durch IR-Spektren, Massenspektren und Molgewichtsbestimmungen sichergestellt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030918
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  • 96
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    Ketosylamin-Umlagerung bei der Umsetzung von D-threo-Pentulose (D-Xylulose) mit α-Aminosäuren (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2873-2876 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ketosylamine Rearrangement of D-threo-Pentulose (D-Xylulose) with α-Amino Acids1)D-threo-Pentulose (1) reacts with glycin (2a), L-α-alanine (2b) or L-valine (2c) to give mixtures of the D-xylose-and D-lycxose-amino acids, from which the D-xylose-amino acids (4a-c) can be obtained pure by chromatography. 2-L-α-alanino-2-desoxy-D-lyxose (5b) and 2-D-valino-2-deoxy-D-lyxose (5c) are obtained by crystallization. The reaction of D-xylulose and glycine is investigated quantitatively.
    Notes: D-threo-Pentulose (1) reagiert mit Glycin (2a), L-α-Alanin (2b) oder L-Valin (2c) zum Gemisch der D-Xylose-und D-Lycxose-Aminosäuren, aus dem sich durch Säulenchromatographie die D-Xylose-aminosäuren (4a-c) rein gewinnen lassen. 2-L-α-Alanino-2-desoxy-D-lyxose (5b) und 2-L-Valino-2-desoxy-D-lyxose (5c) werden durch Kristallisation erhalten. Die Reaktion der D-Xylulose (1) mit Glycin (2a) wird quantitativ verfolgt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030925
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    Direkte Photolyse von Kohlenoxidsulfid in Alkoholen und Acetonitril in Gegenwart von Olefinen. Reaktionen von Triplett-Schwefelatomen mit Norbornen in Äthanol und 1.4-Dioxan (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2894-2901 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Direct Photolysis of Carbonyl Sulfide in Alcohols and Acetonitrile in the Presence of Olefins. Reactions of Triplet Sulfur Atoms with Norbornene in Ethanol and 1, 4-DioxanePhotolysis of COS in methanol as well as in acetonitrile in the presence of cyclohexene or 1-octene gives rise to the formation of the corresponding episulfides due to the addition of triplet sulfur atoms, S(3P). With norbornene, however, episulfide formation ist not observed; only diastereomeric dinorbornyl sulfides 1a and 1b are obtained if the reaction is carried out in ethanol, whereas norbornyl 1,4-dioxanyl sulfide (5) is produced in addition to 1 a and 1 b, if 1,4-dioxane is used as solvent. The mode of formation of these compounds is discussed.
    Notes: Die COS-Photolyse führt in Methanol wie auch in Acetonitril in Gegenwart von Cyclohexen bzw. Octen-(1) zur Bildung der Episulfide durch Reaktion von S(3P)-Atomen mit den Olefinen. Mit Norbornen dagegen wird keine Episulfidbildung beobachtet; die COS-Photolyse in äthanol liefert ausschließlich die beiden diastereomeren Dinorbornylsulfide 1a und 1 b, während in 1.4-Dioxan außerdem noch [Norbornyl-(2)]-[1.4-dioxanyl]-sulfid (5) entsteht. Die Bildungsweisen dieser Verbindungen werden diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030928
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    Phosphororganische Verbindungen, 67. Notiz über die reduktive Umwandlung von Carbonsäuren in ihre Aldehyde (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2984-2986 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030936
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  • 99
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    Polyacetylenverbindungen, 178. Über die Inhaltsstoffe von Grindelia-Arten (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2245-2251 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyacetylenic Compounds, 178. Constituents of Grindelia SpeciesThe investigation of further Grindelia species shows the presence of some new C10-acetylenic compounds (1-3, 8, 9, 13, 14, 22, 23) representing biogenetical relationships in this genus. Feeding experiments furnish more details of the biogenesis of the C10-compounds.
    Notes: In weiteren Grindelia-Arten werden einige neue C10-Acetylenverbindungen (1-3, 8, 9, 13, 14, 22, 23) nachgewiesen, die die biogenetische Beziehung in dieser Gattung aufzeigen. Fütterungsversuche zeigen weitere Einzelheiten über die Biogenese der C10-Verbindungen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030729
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    Beiträge zur Chemie des Siliciums und Germaniums, XI. Darstellung und Untersuchung neuer Jodderivate des Disilans, Trisilans und n-Tetrasilans (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 3028-3033 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Chemistry of Silicon and Germanium, XI. Preparation and Investigation of New Iodine Derivatives of Disilane, Trisilane, and n-TetrasilaneDisilane (Si2H6), trisilane (Si3H8), and n-tetrasilane (n-Si4H10) react with elementary iodine in solution to give partially iodated silanes. The isomer-free compounds have been isolated by gaschromatography in preparative amounts and have been examined by n.m.r. spectroscopy.
    Notes: Bei der Umsetzung von Disilan (Si2H6), Trisilan (Si3H8) und n-Tetrasilan (n-Si4H10) mit elementarem Jod in einem Lösungsmittel wurden teiljodierte Silane gewonnen. Isomerenreine Produkte wurden gaschromatographisch in präparativen Mengen isoliert und NMR-spektroskopisch untersucht.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701031004
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