ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (5,504)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (5,504)
  • 1955-1959
  • 1975  (5,504)
Collection
Keywords
Publisher
Years
  • 1995-1999
  • 1980-1984
  • 1975-1979  (5,504)
  • 1955-1959
Year
  • 101
    Electronic Resource
    Electronic Resource
    Minimization of construction errors in bent-wire protein models (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 633-640 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two kinds of errors are found in protein models made with the tool of Rubin and Richardson. Global errors result from the accumulation of many errors too small to localize, while local errors are assignable to particular bends in the model. We here locate the sources of local errors, and show how to minimize both kinds of errors.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140315
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 102
    Electronic Resource
    Electronic Resource
    Helix-coil transition of poly(γ-benzyl-L-glutamate) in the dioxane-dichloroacetic acid mixture (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 641-648 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal helix-coil transition of four samples of poly(γ-benzyl-L-glutamate) in the dioxane-dichloroacetic acid (DCA) mixture was studied by optical rotatory dispersion method. The transition occurred at very high DCA content (97.5% by weight) in this system. The transition parameters have been evaluated by two methods based on the theories of Zimm and Bragg and of Nagai. The values of the helix initiation parameter and of the enthalpy of transition were found to be (4.4 ± 0.4) × 10-5 and 340 cal/mole, respectively. The range of validity and equivalence of the two methods is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 103
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975) 
    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.1975.360140401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 104
    Electronic Resource
    Electronic Resource
    Heat of interaction of DNA with polylysine and trilysine (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 675-677 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140319
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 105
    Electronic Resource
    Electronic Resource
    Raman studies of the crystalline, solution, and alkaline-denatured states of β-lactoglobulin (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 649-662 
    Details
    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 β-lactoglobulin in the crystalline, freeze-dried, and solution states are compared. The spectra of the freeze-dried and crystalline proteins were practically identical. The conformationally sensitive amide III line appearing at 1242 cm-1 increased in intensity 30% upon dissolution of the protein in water which is interpreted as a conformational change in the disordered chains of the protein. This result appears to be a phenomenon for globular proteins containing a large disordered chain fraction.The alkaline denaturation of β-lactoglobulin was studied. When the pH was increased from 6.0 to 11.0, the amide III line shifted from 1242 to 1246 cm-1, broadened, and decreased in intensity. This is consistent with the conversion of β-sheet regions in β-lactoglobulin to the disordered conformation, as has been proposed by other investigators. At pH 13.5 the amide III shifts to 1257 cm-1 characteristic of a completely disordered protein, indicating that any remaining “core” of β-sheet has been randomized.Several changes in the intensities of the tyrosine and tryptophan vibrations accompany the denaturation. As the pH is increased from 6.0 (native state) to 11.0 (denatured state) the intensity ratio of two tyrosine ring vibrations, I855 cm-1/I830 cm-1, decreases from 1.0:0.9 to 1.0:1.3. The same ratio for a copolymer consisting of 95% glutamic acid and 5% tyrosine at pH 7.0, where the polymer forms a random coil exposing the tyrosine to the aqueous environment, is 1.0:0.62. This ratio more closely resembles that corresponding to β-lactoglobulin at pH 6.0 (native state) than pH 11.0 (denatured state) suggesting that the average tyrosine in the denatured state may be in a more hydrophobic environment than in the native state. A time-dependent polymerization of the denatured protein reported by other investigators and observed by us may account for the change in the tyrosine environment.A tryptophan vibration appearing at 833 cm-1 in the spectrum of the native state becomes weak as the pH is increased to 11.0. The intensity of this line may also reflect the local environment of the tryptophan residue.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140317
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 106
    Electronic Resource
    Electronic Resource
    Condensed states of nucleic acids. II. Effects of molecular size, base composition, and presence of intercalating agents on the Ψ transition of DNAPart I: Cheng and Mohr (1974)5. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 663-674 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular dichroism spectroscopy has been used to investigate the influence of DNA molecular size, base composition, and the presence of intercalating agents upon the Ψ transition of DNA brought about by high concentrations of poly(ethylene oxide) and salt (Lerman (1971) Proc. Natl. Acad. Sci. (U.S.) 68, 1886-1890). A molecular weight of 0.15-3.0 × 106 daltons yields maximum formation of Ψ-DNA. Both the amplitude of the large negative CD band at 265 nm - a chief characteristic of the Ψ state - and the thermal stability of Ψ-DNA increase linearly with increasing mole fraction of guanine plus cytosine in the DNA sample. Either ethidium or proflavine, at concentrations where approximately one dye is bound per 5-10 nucleotide residues, can prevent the transition completely. Striking similarities between the Ψ-DNA produced by poly(ethylene oxide) + salt and the complexes formed between DNA and lysine-rich histone f1 suggest the presence of similar nucleic acid-nucleic acid interactions in both types of condensed phase.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140318
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 107
    Electronic Resource
    Electronic Resource
    Estimation of amino acid residue side-chain absorption in the infrared spectra of protein solutions in heavy water (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 679-694 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The values of maximum frequencies, intensities, and other spectral parameters of the main absorption bands of amino acid residue side-chain groups have been obtained in the 1500-1800-cm-1 region for solutions in heavy water at pD 1-12. It is shown that absorption of residues of asparagine, glutamine, aspartic and glutamic acids, arginine, and tyrosine must be taken into account in quantitative studies of the infrared spectra of polypeptide and protein solutions in heavy water. Examples of separating out the amide I band for ribonuclease A in heavy water are given.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 108
    Electronic Resource
    Electronic Resource
    Neutron-scattering spectroscopy of the α- and β- forms of poly-L-alanine. Motion of the methyl side chain (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 715-721 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Detailed inelastic, incoherent neutron-scattering (INS) spectra are presented for poly-L-alanine in both the α-helical and β-sheet form. Assignments are made from previous normal coordinate calculations. Of particular interest is the methyl torsion at 230 cm-1, which is the strongest peak in the spectrum and is independent of backbone conformation. The height of the potential barrier for methyl group rotation is calculated to be 14 kJ mol-1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 109
    Electronic Resource
    Electronic Resource
    Influence of the sugar configuration on the structure of RNA by conformational analysis of the ribose-phosphate unit (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 695-713 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformation of the ribose-phosphate unit for the four principal configurations of the sugar ring has been studied using the extended Hückel theory and the Lennard-Jones empirical potential. Initially, the oxygen atoms of the p3 and p5 groups were not taken into account. With this restriction, the energy of this residue with regard to the structure of RNA has been minimized for the rotational angles ψ and φ′.The equivalence of the sugar puckering C2′endo ≃ C3′exo and C3′endo ≃ C2′exo has been confirmed. We find that the role of the sugar configuration is important and that there is a difference in the rotations around the bond C3′-O3′ (φ′ angle) according to this configuration. The C3′endo sugar form seems to be energetically preferred for this residue of RNA.The oxygen atoms and the electrostatic interactions were then introduced into the empirical potential. The variation of the energy when varying φ′ for different positions of the p5 group was studied for the main C3′endo and C2′endo configurations of the sugar; in this condition the φ′ rotation is considerably restricted but the allowed regions continue to differ according to the configuration of the sugar considered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 110
    Electronic Resource
    Electronic Resource
    Studies on cyclic peptides. II. Synthesis of cyclic peptides containing sarcosine (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 723-731 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclic peptides containing sarcosine, cyclo-(Pro-Sar-Gly)2, cyclo-(Sar-Sar-Gly)2, cyclo-(Sar4), and cyclo-(Sar6) have been synthesized by the cyclization of the p-nitrophenyl ester of linear peptides. The tert-butoxycarbonyl group was used as the Nα-protecting group, which was removed by acid. Benzyl ester was used to protect the C-terminal. tert-butoxycarbonylpeptide was obtained by the stepwise elongation of the peptide bond by the carbodiimide method. Deblocking and cyclization of the linear peptides gave the cyclic peptides.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 111
    Electronic Resource
    Electronic Resource
    Studies on cyclic peptides. III. The specific interaction of cyclic peptides with benzene and an application of the solvent-induced nmr shift to the conformational analysis of cyclo-(Pro-Sar-Gly)2 (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 733-747 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction between cyclic peptides [cyclo-(Sar4), cyclo-(Pro-Sar-Gly)2, cyclo-(Sar-Sar), and cyclo-(Sar-Gly)] with benzene has been investigated by nmr spectroscopy. The experiment with cyclo-(Sar4) showed that benzene interacted preferentially with the trans peptide bond in a similar manner to the dimethylformamide-benzene interaction. The solvent-induced nmr shift was then applied to the conformational analysis of cyclo-(Pro-Sar-Gly)2 with the aid of the molecular model. The major conformation was proved to possess the C2 symmetry with internally hydrogen-bonded glycine residues, in which all peptide bonds were trans. The interaction of cyclo-(Sar-Sar) and cyclo-(Sar-Gly) with benzene was also studied. The association constant was 0.115-kg solution per mole of cyclo-(Sar-Sar) and 0.089-kg solution per mole of cyclo-(Sar-Gly) in chloroform.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 112
    Electronic Resource
    Electronic Resource
    Investigation of the thermal unfolding of secondary and tertiary structure in E. coli tRNAfMet by high-resolution nmrThe results presented here were taken from the Ph.D. Thesis of K.L.W., submitted December, 1973. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 749-762 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The high-resolution (300 MHz) proton nmr spectrum of E. coli tRNAfMet has been examined in 0.17M NaCl, with and without Mg2+, and at various temperatures. In light of recent studies of other E. coli tRNA and fragments of tRNAfMet, some low field (11-15 ppm) resonances previously assigned to secondary structure base pairs are reassigned to a tertiary structure A14-S4U8 base pair and a protected uridine residue in the anticodon loop. These two resonances and other low field resonances which are assigned to secondary structure base pairs are used to monitor the thermal unfolding of the molecule. In the absence of Mg2+ the tertiary structure base pair is present only to ∼45°C, but in the presence of Mg2+ it remains until at least 70°C. Analysis of the temperature dependence of other low field resonances indicates that the melting of the dihydrouridine stem occurs more or less simultaneously with the loss of tertiary structure. The observation of the resonance from the A14-S4U8 base pair proves that tertiary structure is present in this molecule below 40°C, even in the absence of Mg2+.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 113
    Electronic Resource
    Electronic Resource
    Relaxation kinetics of the triple-stranded helix ⇄ coil transition at short chain length. A model including the staggering of chains (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 763-780 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relaxation kinetics of a staggering zipper model are presented, in which the formation of helical nuclei is regarded to be rate-limiting and in which the sliding of strands along the helices is prohibited. Instead a realignment of staggered chains is only possible via complete uncoiling. While maintaining the third order of the initial reaction as in an all-or-none mechanism, the model predicts a large range of relaxation times, which contribute to the mean relaxation time according to the stability of the individual species and which are weakly coupled in the range of small amounts of helical content. The model can easily be compared to experimental results and agrees well with relaxation data obtained from a triple-helical peptide fragment of collagen. It may be readily expanded to other multistranded helix ⇄ coil transitions with steady-state formation of the individual species and it suggests that the fraying of the helix ends is hidden by the fast-relaxation times due to the equilibration of the shortest helical species.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140408
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 114
    Electronic Resource
    Electronic Resource
    Spécificité de l'interaction DNA-platine dosage du platine, pH métrieUne communication préliminaire de cet article a été faite au Second International Symposium on Platinum Coordination Complexes in Cancer Chemotherapy, 16-18 avril 1973, Université d'Oxford, Angleterre. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 781-799 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Interaction between the sodium salt of a DNA extracted from salmon sperm (41% GC) with [Pt(NH3)4]Cl2, [Pt(NH2—(CH2)2—NH—(CH2)2—NH2Cl]Cl, cis-Pt(NH2—(CH2)2—NH2)Cl2, cis-Pt(NH3)2Cl2, trans-Pt(NH3)2Cl2, K[Pt(C2H4)Cl3], and K2[PtCl4) indicates at least three types of complexation. A correlation is found between the change of pH and the number of platinum atoms fixed per (AT + GC) unit. The first binding site is located on the G-C pairs (guanine-cytosine), most likely the N-7(G) site, as it was shown in a previous study of the guanosine-platinum salts. The fixation of the second platinum atom by the pair (AT + GC) takes place with liberation of protons. In the case of the complexes cis-Pt(NH2—(CH2)2—NH2)Cl2, cis-Pt(NH3)2Cl2, and trans-Pt(NH3)2Cl2 the second interaction seems to involve simultaneously the N-7(A) and the N-1(G) and N-3(C) sites. This latter intercrosslink between guanine and cytosine obviously liberates protons and the decrease of pH is related in this case to the trans effect of the platinum compounds. The first two platinum atoms in the reaction of K2PtCl4] or the Zeise salt, K[Pt(C2H4)Cl3] with DNA are fixed on the G-C pairs. A maximum of six platinum atoms per (AT + GC) unit were fixed in this case. Preliminary experiments with a DNA extracted from bacteria Micrococcus lysodeikticus (72% GC) give similar results.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140409
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 115
    Electronic Resource
    Electronic Resource
    Optical property of bovine plasma albumin between 2 and 82 eVA part of this work was presented at the 4th International Conference on Vacuum Ultraviolet Radiation Physics, Hamburg, Germany (July 1974). (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 839-847 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical constants of bovine plasma albumin in the form of a dry solid film have been determined in the 2-82 eV region of photon energy. The extinction coefficient k was obtained by transmission measurements on thin films on a calcium fluoride substrate and on ultrathin films of polystyrene supported by mesh screen. The refractive index n was determined by a Kramers-Kronig analysis using the measured values of k. The complex dielectric function ε and the energy-loss function -Im(1/ε) for charged particles were derived from the data of n and k. The result for k exhibit, in addition to the well-known absorptions at 4.4, 5.5, and 6.4 eV, a small peak at 7.6 eV, a shoulder around 9.7 eV, and a strong peak at 14.0 eV. A prominent peak at 22.7 eV in the energy-loss function exhibits a large degree of collective nature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140412
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 116
    Electronic Resource
    Electronic Resource
    Equilibrium studies on neutral red-DNA bindingA preliminary account of this work was presented in September, 1974, at the 168th National ACS Meeting in Atlantic City, New Jersey. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 825-837 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spectrophotometric binding studies were undertaken on the interaction of neutral red with native and heat-denatured, sonicated, calf thymus DNA in a 0.2M ionic strength buffer containing Tris-sodium acetate-potassium chloride at 25°C. The pKA of neutral red was found to be 6.81. At pH 5 the binding of protonated neutral red was complicated even at low concentration ratios of dye to DNA. In the pH range 7.5-8.5 the tight binding process could be studied and it was found that both protonated and free base species of neutral red significantly bind with DNA having association constants (in terms of polynucleotide phosphate) of 5.99 × 103 M-1 and 0.136 × 103 M-1, respectively, for native DNA and 7.48 × 103 M-1 and 0.938 × 103 M-1, respectively, for denatured DNA. The pKA value of the neutral red-DNA complexes were 8.46 for native DNA and 7.72 for denatured DNA. These results are discussed in terms of possible binding mechanisms.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140411
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 117
    Electronic Resource
    Electronic Resource
    Variations thermiques, entre 1 et 300°K, de la chaleur specifique de la L-alanine, tri(L-alanine), et de la poly(L-alanine) sous formes α et β (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 801-823 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The heat capacities of L-Alanine, tri(L-alanine), and poly (L-alanine) (α helicoidal form and β pleated sheet structure) have been measured between 1.5 and 300°K with a standard adiabatic calorimeter.In the solid state, the heat capacity is in general dut to three parts which are additive in first-order approximation. (1) The lattice vibrations or “acoustical modes” which are the largest at low temperatures. The low-temperature lattice specific heat is proportional to T, T2, or T3 for an ideal one-, two- or three-dimensional solid, respectively. (2) The so-called group vibrations or “optical modes” which, due to their high frequencies, usually take effect only at higher temperatures. (3) The defects and unharmonic effects.The α-amino acid and its trimer present a specific heat thermal variation characteristic of molecular solids which is correctly fitted with an empirical law proposed by Kitaigorodskii. This author assumes that, for such solids, the molecular lattice point has six degrees of freedom (three of translation and three of rotation). Thus the lattice contribution of the specific heat satisfies the Debye approximation in agreement with the doubling of the number of degrees of freedom per molecule (compared with atomic crystals).The polypeptide behavior is, however, different. The specific heat for each form exhibits a thermal dependence connected with a strong vibrational anisotropy. The model proposed earlier by Tarasov accounts well for these results. In the case of the β form, we have observed the predicted three- and two-dimensional behavior due to the intermolecular H bondings responsible for the sheet structure. For the α form we observed a one-dimensional pattern at higher temperature, since each peptidic chain vibrates separately.The comparison with other spectroscopic and theoretical investigations shows a large discrepancy. However, we have attemped to account for the “optical contribution” to the specific heat of poly(L-alanine) by using a continuum of mean frequencies as suggested by Wunderlich. Vibrational frequency spectra are proposed to explain our results, but the overlapping of acoustical and optical branches in the case of the α form outlines the limits of macroscopic models. It is quite likely that the acoustical spectrum is greatly affected by the intramolecular H bonding.At low temperature the specific heat is a physical property sensitive to the long-range order of the macromolecule, and therefore further spectroscopic and theoretical investigations are necessary to explain correctly these experimental results.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 118
    Electronic Resource
    Electronic Resource
    Conformational states of poly(L-tyrosine) in aqueous solution (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 849-869 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(L-tyrosine) [(L-Tyr)n] has been characterized in aqueous solution using circular dichroism (CD) and infrared (ir) spectroscopy, and ultracentrifugal analysis. Most of the experiments were carried out at 0.01% polymer or less to avoid the complications caused by precipitation previously encountered by others. This permitted us to study solutions of (L-Tyr)n at lower pH values than had been attained previously. Our results show that a transition to an antiparallel-β conformation occurs at pH 11.32 upon titration from higher pH. The β structure is intramolecular when first formed and aggregates with time or upon titration below pH 11. Ultracentrifugal analysis of the intramolecular β conformation shows that it is quite compact, with a frictional coefficient ratio, f/fmin, of 1.09. In addition to the β structure, a nonordered form of the polymer has been obtained below pH 11 by rapid titration of the ionized polyelectrolyte. This form is nonaggregated and was found to have an f/fmin of 1.01, and is therefore almost spherical. The aggregated β form was found to be thermodynamically more stable than the nonordered form at pH 10.7.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140413
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 119
    Electronic Resource
    Electronic Resource
    A new technique for optical observation of the kinetics of chemical reactions perturbed by small pressure changes (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 883-887 
    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.1975.360140415
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 120
    Electronic Resource
    Electronic Resource
    An “acid” structure for polyriboguanylic acid observed by X-ray diffraction (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 889-890 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 121
    Electronic Resource
    Electronic Resource
    On the nonplanarity of the peptide groups in the ω-helix of polypeptides (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 891-893 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140417
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 122
    Electronic Resource
    Electronic Resource
    Conformation of histidine model peptides. II. Spectroscopic properties of the imidazole chromophoreTaken in part from a dissertation submitted by P. E. Grebow in partial fulfillment of the requirements for the Ph.D. degree, University of California, Santa Barbara, 1973. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 871-881 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Semi-empirical molecular orbital calculations have been carried out for the free base and cationic forms of imidazole so as to obtain data which are required for the calculation of the chiroptical properties of molecules that contain this chromophoric group. The polarization, energy, and monopolar charge distribution are reported for the lowest energy electronic transitions. The absorption spectra for imidazole have been determined to 180 nm and circular dichroism spectra for L-histidinol and L-2-amino-1-butanol have been measured.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140414
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 123
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975) 
    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.1975.360140501
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 124
    Electronic Resource
    Electronic Resource
    Structure of the collagen microfibril. A four-strand overlap model (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 895-900 
    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.1975.360140418
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 125
    Electronic Resource
    Electronic Resource
    Studies on deoxyribonucleoprotein structure. Small-angle X-ray scattering in solutions of various ionic strengths (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1133-1142 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cross-sectional radius of gyration of the deoxyribonucleoprotein (DNP) threads was measured by small-angle X-ray scattering in a wide range of ionic strengths (from 0.0005 to 2 M NaCl). For DNP in a solution of low ionic strength, this value is 30 Å. The increase of ionic strength results in partial deproteinization of DNP, while the cross-sectional radius of gyration varies from 25 Å for DNP in 0.7 M NaCl to 10 Å for DNP in 2 M NaCl. It is suggested that gradual deproteinization by the increase of NaCl concentration causes conformational changes, which are associated with the alteration of the DNP superstructure. The data are interpreted on the basis of the superhelical model of DNA packing in DNP; however, the coexistence of superhelical and unfolded regions in the DNP structure is also a possibility.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 126
    Electronic Resource
    Electronic Resource
    The buoyant and potentiometric titrations of human immuno-gamma globulin (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1161-1171 
    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 and potentiometric hydrogen ion titration curves of human immuno-gamma globulin in 3M cesium chloride have been recorded. In addition, the amino acid analysis of the IgG employed has been completed. The hydration of the protein and the variation of the hydration with pH have been calculated from the buoyant density data. The potentiomtric hydrogen ion titration curve has been employed to estimate the intrinsic pK′s of the acidic and histidyl residues of the molecule, and to confirm the hypothesis that it does in fact conform to the oil drop model of protein conformation. Correlations have been drawn between the three sets of data in the following manner. The results of the potentiometric hydrogen ion titration have been checked against the amino acid analysis to determine whether the numbers of groups observed to titrate and the numbers of groups observed in the amino acid analysis do correspond. Second, previous hypotheses as to the direct correlation between potentiometric hydrogen ion titration behaviour and buoyant density titration behaviour have been investigated and substantially confirmed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 127
    Electronic Resource
    Electronic Resource
    On the displacement of cooperative transitions of linear biopolymers by an electric field (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1173-1179 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A basic theory for equilibrium properties of cooperative transitions (particularly helix-coil transformations) of sufficiently long linear biopolymers under the influence of an electric field is developed. General relations for the calculation of the distribution of uninterrupted sequences of elementary subunit states (e.g., helical fragments) as well as the overall degree of transition θ are given. Strong cooperativity is found to permit simplifications. It is shown that only in this case can a practically significant field effect be expected. Numerical results are presented for a special example of experimental interest.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 128
    Electronic Resource
    Electronic Resource
    Nmr study of the structure of short-chain peptides in solution (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1143-1160 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron-mediated spin-spin coupling constant J between the amide NH and the α-CH protons in the dipeptide fragment Cα—CO(NH—CαH)R—C′ONH—Cα is dependent on the dihedral angle of rotation (Φ) around the N—C bond. Measurement of J in a series of zwitterionic dipeptides H3N+—CHR1—CONH—CHR2—CO2- (which is conformationally similar to the dipeptide fragment) in TFA solution shows that J is independent of R1, but dependent on the steric bulk of R2. The data are interpreted in terms of a model that assumes that what we measure is an average value of J—a thermal average over all the possible rotamers. The groups R1 and R2 are, in most cases, sterically kept apart by the trans and planar amide bonds, and hence the independence of J of R1. This model is consistent with the theoretical calculations done on the dipeptide fragment. The effect of the structural characteristics of the side chains (e.g., the effect of lengthening and branching the side chains) on the J values in dipeptides is discussed in the light of the existing results of theoretical calculations.Study of 〈J〉 values in tripeptides (C6H5CH2OCONH—CHR1—CONH—CHR2—CO2CH3, essentially three linked peptide units) shows that electrostatic interaction between the two amide bonds modifies the potential energy surface and the 〈J〉 value of a dipeptide subunit in the tripeptides. Also in some cases, direct steric interaction between the two side chains in the two adjacent dipeptide subunits in the tripeptide affects the potential energy surfaces of the individual dipeptide subunits and hence the 〈J〉 values. The influence of the structural characteristics of the side chains of individual amino acids on structure formation at or beyond the dipeptide level is discussed at various points.The J(NH—αCH) values of CH3CONH—CHR—CONH2 and CH3CONH—CHR—CO2CH3 with the same R are quite different for R = valine, leucine, phenylalanine, methionine, but equal for R = glycine. This, coupled with the fact that one of the carboxamide NH resonances has a chemical shift different from its counterpart in simple amides like CH3CONH2 and the other carboxamide NH has the same chemical shift as its counterpart in CH3CONH2, suggest the presence of a hydrogen bond in dipeptide CH3CONH—CHR—CONH2 with carboxamide NH as the donor. Theoretical evidence for two seven-membered hydrogen-bonded rings with the carboxamide NH as donor and the acetyl oxygen as acceptor is summarized. Our data cannot suggest the number of such hydrogen-bonded rings, nor can they conclude the relative proportion of these rings in a particular dipeptide. A discussion of the difficulty of interpretation is presented and the data are discussed under certain simplifying assumptions.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 129
    Electronic Resource
    Electronic Resource
    The effects of cooperativity, finite chain length, and field-induced changes of the conformational equilibrium on the electric birefringence of polypeptides in the range of the helix-coil transition (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1181-1195 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An electric birefringence apparatus with an He-Ne laser is described, which permits a high sensitivity of measurement for field strengths up to 20 kV/cm and pulse durations between 10-5 to 1 sec. It is applied to poly(γ-benzyl-L-glutamate) and poly(β-benzyl-L-aspartate) in a nonaqueous solvent mixture, especially under the conditions of the helix-coil equilibrium. A theoretical treatment of the problem shows that the usual neglect of end effects is only justified for comparatively long chains. On the basis of a computational procedure taking into account the finite chain lengths, the experimental data for 15 kV/cm reveal an obvious enhancement of the coil-to-helix transition caused by the electric field. This effect is quantitatively confirmed by a pertinent theory. The cooperative parameter σ may be best determined from the initial linear increase of the bire-fringence versus the square of the field strength where the conformational equilibrium is not affected.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 130
    Electronic Resource
    Electronic Resource
    Quantum-mechanical study of the hypochromic effect in polynucleotides. Intra- and interstrand interaction contributions (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1205-1212 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first uv absorption band hypochromism of poly(dA) · poly(dT), poly(dG) · poly(dC), poly(dA), poly(dT), poly(dG), and poly(dC) is calculated with the help of perturbation theory on the basis of monomer characteristics computed by the Pariser-Parr-Pople method taking into account all singly excited configurations. The theoretical results obtained are in good agreement with experimental values of hypochromism. The origin of the hypochromic effect in the double-stranded polynucleotides is investigated. It is shown that intrastrand interactions between the bases make the main contribution to hypochromism (60-76%), while the contribution of the Watson-Crick-pair formation is small (2-12%). The essential part of hypochromism (22-28%) is due to the interstrand interactions between the bases that are not coupled by hydrogen bonds. The discussion of the experimental data shows that the present theoretical investigation could serve as a basis for the correct treatment of experimental data.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 131
    Electronic Resource
    Electronic Resource
    An X-ray diffraction study of poly-L-homoarginine hydrochloride (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1197-1204 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An X-ray study of the synthetic polypeptide poly(L-homoarginine hydrochloride) has been made to investigate whether, like the chemically related polypeptides poly(L-lysine hydrochloride), poly(L-arginine hydrochloride), and poly(L-ornithine hydrobromide), it can undergo conformational transitions merely from variations in its degree of hydration. X-ray photographs of powder and oriented specimens containing one to 15 molecules of water per L-homoarginine hydrochloride residue showed that this polymer forms only a β-pleated-sheet structure. The pleated sheets, formed by antiparallel polypeptide chains hydrogen-bonded to each other, are piled up along the b axis in an alternating sequence (“sandwich structure”). This structure did not appreciably change with variations of the degree of hydration, and the observed reflections at 56% relative humidity (1.8 molecules of water per residue) could be indexed satisfactorily in terms of a monoclinic unit cell, of space group P21, with a = 9.34 Å, b = 40.07 Å, c = 6.94 Å, and γ = 106°. These dimensions are shown by models to be compatible with the proposed structure, and the calculated density of 1.27 g/cm3 agrees well with the experimental value of 1.29 g/cm3. Removal of the last molecule of water results in a very diffuse pattern, while specimens containing 20 molecules of water per residue show only reflections due to water.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 132
    Electronic Resource
    Electronic Resource
    Carbon-13 and proton nmr studies of helix-coil transition of poly(γ-benzyl-L-glutamate) (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1223-1230 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil conformational transition undergone by poly(γ-benzyl-L-glutamate) in solutions of trifluoroacetic acid and deuterated chloroform was studied by proton and carbon-13 nmr. The results indicate that in the case of the solvent-induced helix-coil transition, the side chain assumes a helical conformation before the backbone. In the thermally induced helix-coil transition, the results indicate the existence of an intermediate state, which is between the α-helix and random coil and is free from intramolecular hydrogen bonding.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140611
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 133
    Electronic Resource
    Electronic Resource
    On the various types of circular dichroism induced on acridine orange bound to poly(S-carboxymethyl-L-cysteine) (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1213-1221 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular dichroism and absorption spectra are measured on mixed solutions of acridine orange and poly(S-carboxymethyl-L-cysteine) at different pH and P/D mixing ratios. The observed circular dichroism spectra are classified into several types, mainly based on the number and sign of circular dichroic bands in the visible region. Three of them are associated with the absorption spectra characteristic of dimeric dye or higher aggregates of dye. Type I is observed with solutions, of which the pH is acid and P/D is higher than 4, and it has an unsymmetrical pair of positive and negative dichroic bands at 470 and 430 nm. This type is induced on the dye bound to the polymer in the β-conformation. Types II and III are considered to be characteristic of randomly coiled polymers. Type II is exhibited by solutions of P/D higher than 1 at pH 5-7 and has two dichroic bands around the same wavelengths as Type I but with opposite signs and an additional positive band at 560 nm. Type III, shown by solutions of P/D 2-0.6 at pH 6-10.5, has three dichroic bands around the same wavelengths as Type II but with signs opposite to it. The other two types of circular dichroism, induced for the solutions of P/D less than 1 at slightly acid pH, are associated with the absorption spectra of monomeric dye and are observed with disordered or randomly coiled polymer. They have a pair of dichroic bands at 540 and 425 nm, and the signs of these bands are opposite to each other in these two types.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140610
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 134
    Electronic Resource
    Electronic Resource
    Basic polypeptides as histone models. Synthesis, conformation, and interaction with DNA of statistical copolymers (Lysx,Alay)n (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1231-1244 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Statistical copolymers (Lysx,Alay)n were synthesized by copolymerization of N-carboxyanhydrides of L-amino acids. The conformation of copolymers in aqueous solutions was investigated using circular dichroism (CD). Calculations based on the CD data showed that polymers (Lysx,Alay)n can exhibit a random conformation, an α-helix, and a β-structure in various ratios. CD spectra of complexes of copolymers with DNA prepared by gradual dialysis from a high ionic strength to 0.15 M NaCl can be correlated with the copolymer conformation in medium and high ionic strength. For copolymers forming an α-helix and β-structure, these spectra show resemblance with similar spectra of complexes of those histones that are able to exhibit ordered conformations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140612
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 135
    Electronic Resource
    Electronic Resource
    Characterization of the A ⇄ B transition of DNA in fibers and gels by laser Raman spectroscopy (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1245-1257 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Both Raman spectra and X-ray diffraction patterns have been obtained from oriented fibers of sodium deoxyribonucleic acid (Na-DNA) as a function of salt content and relative humidity. We have confirmed the previously reported X-ray results that, for oriented fibers, the A-form always exists between 75 and 92% relative humidity and that the conformation will change to the B-form at 92% relative humidity only if an excess (3-5%) of added salt is present. Oriented fibers containing low amounts of added salt remain in the A-type conformation at 92% relative humidity and higher. An exact correlation has been found between the familiar A- and B-type X-ray diffraction patterns of DNA fibers and the Raman spectra previously reported without X-ray verification from this laboratory for the A- and B-forms. In particular, a band at 807 cm-1 was always present when a fiber showed the A-type diffraction pattern, and this band shifts to 790 cm-1 in the B-form. Using the Raman spectrum to determine the specific conformation of DNA in samples less amenable to X-ray analysis, we have studied the A ⇄ Btransformation in unoriented fibrous masses of DNA and in concentrated, oriented gels. We find that in unoriented fibrous masses, the A ⇄ B transition always occurs at 92% relative humidity even at very low salt concentration (0-4%). However, in oriented DNA gels at low salt, the A-form can persist as a metastable state to concentration as low as 20% DNA. The origin of the bands at 807 and 790 cm-1 and the possible biological implications of these findings are discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140613
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 136
    Electronic Resource
    Electronic Resource
    Analysis of the effects of chloride and 2,3-diphosphoglycerate on the cooperative binding of oxygen to hemoglobin (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1273-1281 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of experimental equilibrium constants for the oxygenation of hemoglobin leads to a plausible mechanism for the effect of pH and of chloride ions on cooperativity in hemoglobin. According to this mechanism, the structural changes responsible for cooperativity in chloride- and 2,3-diphosphoglycerate-free hemoglobin are affected only slightly by changes in pH, and the effect of chloride can be accounted for by sequential binding and release of chloride ions during oxygenation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140615
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 137
    Electronic Resource
    Electronic Resource
    Conformational geometry and vibrational frequencies of nucleic acid chains (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1259-1271 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Normal coordinate analysis of diethyl phosphate has been made, which predicts all observed Raman frequencies in the range 170-1300 cm-1. The force constants from this calculation have been transferred to a vibrational calculation for a simplified model of the backbone of nucleic acids, which also involves the —O—PO2-—O phosphate group and the —C5′—C4′—C3′—linkage of the ribose. The coordinates of these atoms are those recently given by Arnott and Hukins, which place the ribose ring of B-DNA in a C3′-exo conformation. This simple polymer model appears to be able to describe adequately the frequency-dependent changes observed in the Raman spectra arising from the backbone vibrations of nucleic acid in going from the B- to A-form. The symmetric —O—P—O— diester stretch increases in frequency from about 787 cm-1 in the B-form to 807 cm-1 in the A-form. The increased frequency characteristic of the A-form is due to the combining of the diester stretch with vibrations involving the C5′, C4′, and C3′ nuclei. The frequency of the symmetric —O—P—O— diester stretch is shown to be very dependent on the conformation of the ribose ring, indicating that in polynucleotides the ribose ring takes on one of two rigid conformations: C3′-endo for A-form or C3′-exo for B-form and “disordered” polynucleotides. The calculation lends confirmation to the atomic coordinates of Arnott and Hukins since the use of other geometries with the same force constants failed to give results in agreement with experimental evidence. The calculations also demonstrate the lowering effect of hydration on the anionic PO stretching frequencies. Experimental results show that the 814-cm-1 band observed in the spectra of 5′GMP gel arises from a different vibrational mode than that of the 814-cm-1 band of A-DNA.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140614
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 138
    Electronic Resource
    Electronic Resource
    Levans. II. Light-scattering and sedimentation data of Streptococcus salivarius levan in water (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1283-1292 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular weights and radii of gyration of Streptococcus salivarius levan fractions were obtained from light-scattering measurements in water. Sedimentation coefficients and partial specific volumes of the fractions were also obtained. Double logarithmic plots of [η] versus M̄w and S0 versus M̄w yielded slopes having values of 0.17 and 0.62, respectively. The data and various calculated parameters show that levan from Streptococcus salivarius is highly branched and behaves hydrodynamically as a compact particle of spherical symmetry.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140616
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 139
    Electronic Resource
    Electronic Resource
    Magnetic susceptibility of ferrihemoglobin in water and 5% t-butanolPublication 81 from the Laboratory for Biophysical Chemistry. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1293-1304 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molar magnetic susceptibility of ferrihemoglobin solutions, as a function of pH and temperature using the nmr technique of Evans, in water and 5% t-butanol has been determined. Results suggest that within a small pH region, the conventional analysis of magnetic susceptibility in terms of high-spin and low-spin contributions breaks down. The implication of this is discussed in terms of possible conformational change involving two subspecies. The effect of t-butanol is also discussed in terms of the t-butanol effect on water.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140617
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 140
    Electronic Resource
    Electronic Resource
    The ultraviolet transitions of the ethidium cation (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1309-1312 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140619
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 141
    Electronic Resource
    Electronic Resource
    Signalstoffe und Chemorezeption bei niederen Pflanzen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 50-58 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 142
    Electronic Resource
    Electronic Resource
    Lehrbuch der Organischen Chemie. Von R. T. Morrison und R. N. Boyd. Verlag Chemie GmbH, Weinheim/Bergstr. 1974. Aufl., XXVIII, 1349 S., 225 Abb., 46 Tab., geb. DM 78,- (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 65-65 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 143
    Electronic Resource
    Electronic Resource
    mini-chiuz (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. A18 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 144
    Electronic Resource
    Electronic Resource
    Photochromie und photochrome Verbindungen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 85-95 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 145
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975) 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 146
    Electronic Resource
    Electronic Resource
    Zellbiologie. Von E. J. Ambrose und D. M. Easty, übersetzt von V. Ceccarelli-Dennler. 1. Aufl. 1974. Verlag Chemie GmbH, Weinheim, XI, 544 S., 357 Abb., brosch. DM 68,- (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 98-98 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 147
    Electronic Resource
    Electronic Resource
    Phosphorverbindungen und ihre technische Bedeutung (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 109-116 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 148
    Electronic Resource
    Electronic Resource
    Manipulieren in molekularen Dimensionen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 173-182 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 149
    Electronic Resource
    Electronic Resource
    Süßstoffe - Entwicklungen und Tendenzen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 142-145 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090503
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 150
    Electronic Resource
    Electronic Resource
    Über den Leuchtschirm der Farbbildröhre (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 163-172 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090602
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 151
    Electronic Resource
    Electronic Resource
    mini-chiuz (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. A54 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 152
    Electronic Resource
    Electronic Resource
    Physikalische Methoden in der Chemie: ESR-Spektroskopie organischer Radikale II (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 43-49 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 153
    Electronic Resource
    Electronic Resource
    Mikrobielle Eiweißgewinnung aus Kohlenwasserstoffen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 59-64 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 154
    Electronic Resource
    Electronic Resource
    Chronik (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 66-66 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 155
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975) 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 156
    Electronic Resource
    Electronic Resource
    Röntgenstrukturuntersuchung von Flüssigkeiten (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 99-107 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 157
    Electronic Resource
    Electronic Resource
    Pilzfarbstoffe (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 117-123 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 158
    Electronic Resource
    Electronic Resource
    mini-chiuz (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. A44 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 159
    Electronic Resource
    Electronic Resource
    Tierische Viren und ihre Wirtszellen (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 146-158 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 160
    Electronic Resource
    Electronic Resource
    Photosynthese und pflanzliche Produktivität. Von P. Böger. Konstanzer Universitätsreden Nr. 76. Druckerei und Verlagsanstalt Konstanz Universitätsverlag GmbH. Konstanz 1975. 48 S., 10 Abb., 2 Kunstdrucktafeln, 8 Tab., DM 17,80 (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 159-159 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090507
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 161
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975) 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 162
    Electronic Resource
    Electronic Resource
    Das Experiment: Chemische Zaubertricks (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. 191-193 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die hier beschriebenen Experimente erschienen unter dem Titel “Producing a Chemistry Magic Show” im August-Heft 1975 von “Journal of Chemical Education”. Die Autoren sind Philip S. Bailey, Christina A. Bailey, John Andersen, Paul G. Koski und Carl Rechsteiner. Wir danken dem Herausgeber für die Erlaubnis, den Artikel zu übersetzen und nachzudrucken. Vielleicht ergibt sich zum Jahresende hier und da eine Gelegenheit, die Freude an der Chemie durch diese chemischen „Zaubertricks“ ein wenig anzufeuern. Es versteht sich von selbst, daß einige der Experimente nicht unter dem Weihnachtsbaum, sondern nur mit den entsprechenden Vorsichtsmaßnahmen in einem Labor oder Hörsaal ausgeführt werden sollten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 163
    Electronic Resource
    Electronic Resource
    mini-chiuz (1975)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 9 (1975), S. A68 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19750090609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 164
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975) 
    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.19751080101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 165
    Electronic Resource
    Electronic Resource
    Zur Kenntnis des Narciclasins (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 445-463 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of NariciclasineFrom narciclasine (2a), the acetonide 8a and its oxidation product 10 are prepared. 10 isomerizes easily to give 11. Catalytic hydrogenation of 2a yields a mixture of dihydronarci-clasines from which the pure cis- and trans-isomers 14a and 15a can be obtained via the tetraacetates. As a by-product of the hydrogenation, isonarciclasine (16a) is isolated. The relative configuration of narciclasine (as represented by formula 2a) is established by the n. m. r. spectra of 15b and 16b. Lycoricidine and margetine are shown to be identical; their configuration is as shown in formula 2b. Some biological tests are reported.
    Notes: Aus Narciclasin (2a) wird das Acetonid 8a und dessen Oxidationsprodukt 10 dargestellt. 10 wird leicht zu 11 isomerisiert. Das bei der katalytischen Hydrierung von 2a anfallende Gemisch der Dihydronarciclasine wird über die Tetraacetate in die cis- und trans-Verbindungen 14a und 15a aufgetrennt. Als Nebenprodukt der katalytischen Hydrierung entsteht Isonarciclasin (16a). Mit Hilfe der NMR-Spektren von 15b und 16b läßt sich die relative Konfiguration des Narciclasins entsprechend 2a beweisen. Lycoricidin und Margetin sind identisch und haben die Konfiguration 2b. Über einige biologische Teste wird berichtet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 166
    Electronic Resource
    Electronic Resource
    Komplexchemie reaktiver organischer Verbindungen, V. Reaktionen aliphatischer Diazoverbindungen mit thermolabilen Mangan-Komplexen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 486-499 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, V. Reaction of Aliphatic Diazo Compound with Thermolabile Manganese ComplexesAliphatic diazo compounds react with the manganese- tetrahydrofurane complexes 1 and 2, respectively, to yield olefine, ketimine or carbene complexes: 3-diazo-2- butanone (3b) reacts with 2 under intramolecular hydride transfer to give the buten-2- one complex 7, while 3-diazocamphor (3c) leads to the 3-iminocamphor complex 8. Benzolyphenyldiazomethane (3a), diphenyldiazomethane (9a), and its p-substituted derivatives 9b-f are shown to be preliminary stages for the stable carbene complexes 4, 10, and 11, the spectra of which are discussed. The diphenylcarbene ligand can be split off by triphenylphosphine, carbon monoxide, ammonium cerium(IV) nitrate, and by thermolysis.
    Notes: Aliphatische Diazoverbindungen reagieren mit den Mangan-THF- Komplexen 1 bzw. 2 zu Olefin-, Ketimin- oder Carben-Komplexen: Während 3-Diazo-2-butanon (3b) mit 2 unter intramolekularer Hydridverschiebung den Buten-2- on-Komplex 7 ergibt, bildet 3-Diazo-campher (3c) bei Umsetzung mit 2 den 3-Iminocampher-Komplex 8. Benzoylphenyldiazomethan (3a) sowie Diphenyldiazomethan (9a) und seine p- substituierten Derivate 9b-f verhalten sich gegenüber 1 und 2 als Vorstufen für die stabilen Carben-Komplexe 4, 10 und 11, deren Spektren diskutiert werden. Der Diphenylcarben-Ligand in 11a kann mit Triphenylphosphin, Kohlenmonoxid und Ammoniumcer(IV)-nitrat sowie durch Thermolyse abgespalten werden.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080213
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 167
    Electronic Resource
    Electronic Resource
    Photochemische Dimerisierung von 1,4- Dialkinylbenzolen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 528-537 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Dimerisation dof 1,4-DialkynylbenzenesOn irradiation with ultraviolet light 1,4-diethynylbenzene (4a) forms blue unstable 6-ethynyl-1-(4- ethynylphenyl)azulene (5) and 6-ethynyl-2-(4-ethynylphenyl)azulene (6) besides polymers. The photolysis of 1,4-bis(phenylethynyl)benzene (4b) yields stable green 2,3-diphenyl-6-phenylethynyl-1-[4- (phenylethynyl)phenyl]azulene (9) and the isomeric naphthalene 11. Products of catalytic reduction of 5, 9, and 11 are described.
    Notes: Aus 1,4-Diäthinylbenzol (4a) entstehen bei Bestrahlung mit ultraviolettem Licht das wenig beständige, blaue 6-Äthinyl-1-(4-äthinylphenyl)azulen (5) und 6-Äthinyl-2-(4-äthinylphenyl)-azulen (6) neben polymeren Produkten. Dagegen führt die Photolyse von 1,4-Bis(phenyl-äthinyl)benzol (4b) zu dem beständigen grünen 2,3-Diphenyl-6-phenyläthinyl-1-[4-(phenyl-äthinyl)phenyl]azulen (9) und dem isomeren Naphthalin-Derivat 11. Reduktionsprodukte von 5, 9 und 11 werden beschrieben.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080218
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 168
    Electronic Resource
    Electronic Resource
    Derivate des Methylendioxybenzols, 40. Synthese des Ferrugons und des Pseudoferrugons (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 561-568 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Derivatives of Methylendioxybenzene, 40. the Synthesis of Ferrugone and PseudoferrugoneThe isoflavones ferrugone (1a) and pseudoferrugone (1a) as well as their dihydro derivatives 2a and b are prepared from the apione derivatives 5f of 6f and the chromene or chroman derivatives 4d and 3p.
    Notes: Die Isoflavone Ferrugon (1a) und Pseudoferrugon (1b) sowie die Dihydroverbindungen 2a und b werden durch Reaktion der Apionderivate5f und 6f mit den Chromen- bzw. Chroman-derivaten 4d bzw. 36p dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 169
    Electronic Resource
    Electronic Resource
    Methylendioxyhetarene, 1. Zur Darstellung von 3,4- Methylendioxythiophen-, -furan- und pyrrol- abkömmlingen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 569-575 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Methylenedioxyhetarenes, 1. On the Preparation of 3, 4- Methylenedioxythiophene-, furan- and -pyrrole DerivativesMethylenation experiments with 3, 4-dihydroxy compounds of diethyl thiophene-, furan-, 1-phenyl-, and 1- (ethoxycarbonylmethyl)-2, 5-pyrroledicarboxylate are reported. Methylenations lead only with diethyl 3, 4-dihydroxy-2, 5- thiophenedicarboxylate (1) to the 3, 4- methylenedioxythiophene derivatives 2 and 3 with formation of diethyl dithieno[3, 4-b: 3′, 4′- g]tetroxecin-1, 3, 7, 9-tetracarboxylate (4) as by- product. The furan- (5a) and pyrrole derivatives 7a and b give the tetraethyl difuro- (6) and dipyrrolo[3, 4-b: 3′, 4′-g]tetroxecin- 1, 3, 7, 9-tetracarboxylates 8a and b, respectively.
    Notes: Es wird über Methylenierungsversuche an 3,4-Dihydroxy- Verbindungen der Thiophen-Furan-, 1-Phenyl- und 1- (Äthoxycarbonylmethyl)-2,5-pyrroldicarbonsäure- diäthylester berichtet. Die Methylenierungen führen nur beim 3,4-Dihydroxy-2,5-thiophendicarbonsäure-diäthylester (1) zu den 3,4-Methylendioxythiophen-Derivaten 2 und 3, wobei als Nebenprodukt der Dithieno[3,4-b: 3′,4′-g]tetroxecin-1,3,7,0-tetracarbonsäure- tetraäthylester (4) gebildet wird. Bei dem Furan- (5a) und den Pyrrol-Derivaten 7a und b entstehen die Difuro- (6) bzw. die Dipyrrolo[3,4- b: 3′,4′-g]tetroxecin-1,3,7,9- tetracarbonsäure-tetraäthylester 8a, b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080222
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 170
    Electronic Resource
    Electronic Resource
    Reaktionen von N, N-Dialkyl- und N, N-Diarylsulfamiden mit Chlorsulfonylisocyanat (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 618-622 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of N, N-Dialkyl- and N, N-Diarylsullfamides with Chlorosulfonyl IsocyanateChlorosulfonyl isocyanate reacts with N, N-dialkyl- or N, N-diarylsulfamides to give the so far unknown N-chlorosulfonyl-N′-(dialkyl- and -diarylsulfamoyl)ureas (3a-e), which may be hydrolysed to the corresponding N-(dialkyl- and -diarylsulfamoyl)ureas (4a-e). The pyrolysis of 3a-e leads to the formation of the known sulfamoyl chlorides.
    Notes: Durch Umsetzung von Chlorsulfonylisocyanat mit N, N-Dialkyl- oder N, N-Diarylsulfamiden erhält man die bisher unbekannten N-Chlorsulfonyl-N′-(dialkyl- und -diarylsulfamoyl)harnstoffe (3a-e), die sich zu N-(Dialkyl- und-Diarylsulfamoyl)harnstoffen (4a-e) hydrolysieren lassen. Die Pyrolyse von 3a-e liefert die bekannten Sulfamidsäurechloride.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080227
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 171
    Electronic Resource
    Electronic Resource
    Zur Photochemie des Allens (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 657-663 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Photochemistry of AlleneAcetophenone-sensitized irradiation of allene yields a complex mixture of products, from which the allene dimer 1, the trimers 2 and 3, and the ketones 4 and 5 have been isolated. This is in contrast to the reported thermal di- and trimerization of allene, which lead to products such as 1, 8-12. The planar allene triplet 13, derived by way of a nonvertical triplet-triplet energy transfer, presumably plays a key role in the photosensitized oligomerization of allene. Also, the formation of the ketone 5 is easily explained in terms of an attack of 13, through its central C-atom to the o-position of the acetophenone, to give 16, which cyclizes ultimately to yield 5. At 240°C, 5 undergoes fragmentation to the starting materials. The α,β-unsaturated ketone 4 arises through a [2 + 2]-photocycloaddition reaction of the 3(n,π*) state of acetophenone to methylacetylene via the oxetene intermediate 6, followed by ring-opening.
    Notes: Die acetophenon-sensibilisierte Belichtung von Allen liefert eine komplexe Produktmischung, aus der sich das Allendimere 1, die Trimeren 2 und 3 sowie die Ketone 4 und 5 isolieren lassen. Dieser Befund steht im Gegensatz zur beschriebenen thermischen Di- und Trimerisierung des Allens, die zu 1, 8-12 führt. Eine Schlüsselrolle bei der photosensibilisierten Allen-Oligomerisierung spielt vermutlich das durch nichtvertikale Triplett-Triplett-Energieübertragung gebildete planare Allen-Triplett 13. Auch die Entstehung des Bicyclo[4.2.0]octadien-Ketons 5 erklärt sich zwanglos durch einen Angriff von 13 mit seinem mittleren C-Atom in der o-Position des Acetophenons unter Bildung der Zwischenstufe 16, die Ringschluß zu 5 erfährt. Bei 240°C erleidet 5 Rückspaltung in die Ausgangskomponenten. Das α,β-ungesättigte Keton 4 ist dagegen Ergebnis einer [2 + 2]-Photocycloaddition des Acetophenons im 3(n,π*)-Zustand an Methylacetylen zum Oxeten 6 mit anschließender Ringöffnung.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080231
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 172
    Electronic Resource
    Electronic Resource
    Organische Schwefelverbindungen, XI. Synthese von 1,3-Oxathiol-spirofuranonen und Furanon-spirodihy-drothiopyranen aus 4-Thioxo-tetrahydrofuran-3-onen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 673-682 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organosulfur Compound, XI. Synthesis of 13-3-Oxathiol-spirofuranones and Furanone-spirodihydrothiopyrans from 4-Thioxotetrahydrofuran-3-onesHeterocyclic, non-enolisable α-oxo-thioketones of furan-type 9 have been prepared for the first time. These highly unstable compounds undergo dimerisation and subsequent elimination of sulfur to give 1,3-oxathiol-spirofuranones 11. In competition with this process reaction with the eliminated active sulfur can occur to yield a dispiro-1,2,4-trithiolan 10a. In the presence of dimethylbutadiene the new α-oxo-thioxofurans 9 react according to the Diels-Alder principle to form the furanone-spirodihydrothiopyrans 13. The reaction mechanisms are discussed.
    Notes: Es werden erstmals heterocyclische, nicht enolisierbare α-Oxo-thioketone vom Furantyp (9) hergestellt, die außerordentlich instabil sind und unter Dimerisierung mit anschließender Schwefeleliminierung reagieren, wobei die bisher unbekannten 1,3-Oxathiol-spirofuranone 11 entstehen. In Konkurrenz hierzu kann Reaktion mit dem bei der Fragmentierung gebildeten aktiven Schwefel unter Bildung eines Dispiro-1,2,4-trithiolans (10a) eintreten. In Gegenwart von Dimethylbutadien reagieren die neuen α-Oxo-thioxo-furane 9 ausschließlich nach dem Diels-Alder-Prinzip unter Bildung der Furanon-spirodihydrothiopyrane 13. Die Reaktions-mechanismen werden diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080233
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 173
    Electronic Resource
    Electronic Resource
    Übergangsmetall-substituierte VB-Elementsysteme, V. Bis(VIA-metall)methylstibine - Darstellung, Quartärisierung und Oxidation (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 700-715 
    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 Substituted VB Element System. Bis(VIA metal)methylstibines-Preparation, Quaternization and OxidationCH3SbBr2 reacts with the transition metal anions of Na[Fe(CO)2π-C5H5] and Na[M(CO)3π-C5H5] (M=Cr, Mo, W) to give CH3Sb[Fe(CO)2π-C5H5]2 and CH3Sb[M(CO)3π-C5H5]2 (M=Cr, Mo, W). via stepwise metalation. Starting with the primary substitution products BrCH3Sb—M(CO)3π-C5H5 (M=Mo, W) the heteronuclear species π-C5H5(CO)3Cr—Sb-(CH3)—M(CO)3π-C5H5 (M=Mo, W) and π-C5H5(CO)3Mo—Sb(CH3)—W(CO)3π-C5H5 can be obtained. Reactions with alkyl halides result in the quaternization of the Sb-atom or the cleavage of the Sb—M bond. In the first case metal substituted Sb-cations of the type [{π-C5H5(CO)3M}2Sb(CH3)R]⊕ (M=Mo, W; R=CH3, C2H5, C6H5CH2) are formed, which can also be synthesized by reaction of monometalated stibines with metal halides [{e. g. π-C5H5(CO)3Mo—Sb(CH3)2 and π-C5H5(CO)3MoBr]. Bromine adds on VB element, to yield transition metal derivatives with presumable pentacoordinated antimony ([π-C5H5(CO)3W]2SbCH3Br2). The chemical and spectroscopic properties of the new antimony transition metal complexes are reported.
    Notes: Die Umsetzung von CH3SbBr2 mit den Übergangsmetall-Anionen von Na[Fe(CO)2π-C5H5] und Na[M(CO)3π-C5H5] (M=Cr, Mo, W) führt unter stufenweiser Metallierung zur Bildung von CH3Sb[Fe(CO)2π-C5H5]2 und CH3Sb[M(CO)3π-C5H5]2 (M=Cr, Mo, W). Ausgehend von den primären Substitutionsprodukten BrCH3Sb—M(CO)3π-C5H5 (M=Mo, W) Können die heteronuclearen Spezies π-C5H5(CO)Cr—Sb(CH3)—M(CO)3π-C5H5 (M=Mo, W) und π-C5H5(CO)3Mo—Sb(CH3)—W(CO)3π-C5H5 erhalten werden. Reaktionen mit Alkylhalo-geniden verlaufen unter Quartärisierung am Sb-Atom oder Spaltung der Sb—M-Einheit. Im ersten Fall werden metallsubstituierte Sb-Kationen der Form [{π-C5H5(CO)3M}2Sb(CH3)R]⊕; (M=Mo, W; R=CH3, C2H5, C6H5CH2) gebildet, die auch aus monometalliertem Stibin und komplexem Metallhalogenid zugänglich sind [z. B. π-C5H5(CO)3MoSb(CH3)2 und π-C5H5(CO)3MoBr]. Die Einwirkung von Brom verläuft unter Addition am VB-Element und liefert Übergangsmetallderivate mit vermutlich pentakoordiniertem Antimon([π-C5H5(CO)3W]2sbCH3Br2). Die chemischen und spektroskopischen Eigenschaften der neuen Antimon-Übergangsmetallkomplexe werden beschrieben.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080236
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 174
    Electronic Resource
    Electronic Resource
    Übergangsmetall-substituierte VB-Elementsysteme, VI. Bis(VIA-metall)methylstibine als monofunktionelle Ligandsysteme in Übergangsmetallkomplexen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 716-723 
    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 Substituted VB Element System. Bis(VIA metal)methylstibines as Monofunction Ligands in Transition Metal ComplexesThe photochemical or thermal reaction of the metal corbonyls M(CO)6 (M=Cr, Mo, W), π-C5H5Mn(CO)3, and Fe2(CO)9 with the dimetalated stibines CH3Sb-[M′(CO)3π-C5H5]2 (M′=Cr, Mo, W) proceeds with elimination of CO or Fe(CO)5, yielding the neutral single antimony-bridged trinuclear complexes (CO)5M—Sb(CH3)[M′L4]2, π-C5H5(CO)2Mn—Sb(CH3)[M′L4]2, and (CO)4Fe-Sb(CH3)[M′L4]2. The new compounds are characterized by means of spectroscopy.
    Notes: Die photochemische bzw. thermische Umsetzung der Metallcarbonyle M(CO)6 (M=Cr, Mo, W), π-C5H5Mn(CO)3 und Fe2(CO)9 mit den dimetallierten Stibinen CH3Sb-[M′(CO)3π-C5H5]2 (M′=Cr, Mo, W) liefert unter Eliminierung von CO bzw. Fe(CO)5 die neutralen, einfach antimonverbrückten Dreikernkomplexe (CO)5M—Sb(CH3)[M′L4]2, π-C5H5(CO)2Mn—Sb(CH3)[M′L4])2 und (CO)4Fe—Sb(CH3)[M′L4]2, Die neuen Verbindungen werden spektroskopisch charakterisiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080237
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 175
    Electronic Resource
    Electronic Resource
    Polyacetylenverbindungen, 232. Weitere Inhaltsstoffe der Gattung Dendranthema (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 735-738 
    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, 232. Further Constituents of the Genus DendranthemaThe genus Dendranthema, also listed as a section of Chrysanthemum, is characterized by the occurrence of 6-ring-enol ether polyynes. The structure of three new compounds has been elucidated (10-12).
    Notes: Die auch als Sektion von Chrysanthemum geführte Gattung Dendranthema ist durch das Vorkommen von 6-Ring-enolätherpolyinen charakterisiert. Drei neue Verbindungen werden in ihrer Konstitution geklärt (10-12).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 176
    Electronic Resource
    Electronic Resource
    Die Ozonolyse von 3,4-cis-Diacetyl-1,2,3,4-tetramethyl-1-cyclobuten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 749-753 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ozonolyse of 3,4-cis-Diacetyl-1,2,3,4-tetramethyl-1-cyclobuteneThe ozonolysis of the title compound 3 gives an ozonide (9) with trans-acetyl groups in high yield. Only a two step transformation of the primary ozonide to the final ozonide via a well defined intermediated (5) can explain this result.
    Notes: Die Tasache, daß die Ozonolyse der Titelsubstanz 3 in CFCl3 in hoher Ausbeute ein Ozonid (9) mit trans-ständigen Acetylgruppen liefert, bewiest, daß der Übergang vom Primärozonid zum Ozonid nicht einstufig, sondern über ein definiertes Zwischenprodukt (5) verläft.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 177
    Electronic Resource
    Electronic Resource
    Untersuchungen an Stoffwechselprodukten von Mikroorganismen, VIII. Aldgamycin F, ein neues Antibiotikum aus Streptomyces lavendulae (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 780-789 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigation on Metabolites of Microorganisms, VIII. Aldgamycin F, a New Antibiotic from S. lavendulaeThe new antibiotic aldgamycin F was isolated from cultures of S. lavendulae, for which we suppose structure. 7.
    Notes: Aus Kulturen von S. lavendulae wurde das neue Antibiotikum Aldgamycin F isoliert, für das wir Struktur 7 vorschlagen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080311
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 178
    Electronic Resource
    Electronic Resource
    Die Stereochemie der Spaltung chiraler acyclischer quartärer Phosphoniumsalze zu tertiären Phosphinoxiden mit Alkalialkoholat (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 803-812 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry of the Alkali Alcoholate-induced Fission of Chiral Acyclic Quaternary Phosphonium Salts to Tertiary Phosphine OxidesThe stereochemical course of the sodium ethanolate-induced fission of chiral acyclic quaternary phosphonium salts 1-5 to tertiary phosphine oxides 6-10 is (with one exception) the same as that of the cleavage of these salts by sodium hydroxide. However, in most cases the stereoselectivity is remarkably lower in the alcoholate-induced fission than in the reaction with sodium hydroxide.
    Notes: Die beobachtete Brutto-Stereochemie der Spaltung chiraler acyclischer quartärer Phosphoniumsalze 1-5 zu tertiären Phosphinoxiden 6-10 mittels Natriumäthylat ist  -  mit einer Ausnahme  -  prinzipiell die gleiche wie bei der Spaltung der betreffenden Salze mit Natrium-hydroxid. Die Stereoselektivität ist dagegen bei der Spaltung mit Alkoholat meist deutlich geringer als bei der Reaktion mit Natriumhydroxid.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080313
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 179
    Electronic Resource
    Electronic Resource
    Die Primärprodukte der Carbonsäurehydrazid/Chlorphosphoran-Reaktion: 1,3,4,2λ5-Oxadiazaphospholine (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 820-830 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Primary Products of the Carbohydrazide/Chlorophosphorane Reaction:. 1,3,4,2λ5-OxadiazaphospholinePhosphorus pentachloride and other at least difunctional chlorophosphoranes react with acylhydrazines and with N-acyl-N′-phenylhydrazines to give 1,3,4,2λ5-oxadiazaphospholines 3. Pentacoordination at phosphorus is unexpected stable in these rings. The compounds are characterized by n. m. r. and mass spectrometry. They are more or less thermolabile and decompose eliminating phosphine oxide or a phosphorus oxide chloride. Electron releasing substituents at the phosphorus and electron withdrawing substituents at the nitrogen atom increase the rate of decomposition. With triethylamine the compounds 3 loose hydrogen chloride and yield the dimers 4 of 1,3,4,2λ5-oxadiazaphospholes.
    Notes: Phosphorpentachlorid und andere mindestens difunktionelle Chlorphosphorane reagieren mit Acylhydrazinen sowie N-Acyl-N′-phenylhydrazinen zu den 1,3,4,2λ5-Oxadiazaphospholinen 3 mit unerwartet stabiler Pentakoordination am Phosphor. Die Verbindungen werden NMR- und massenspektrometrisch charakterisiert. Sie sind mehr oder weniger thermolabil und zerfallen unter Abspaltung von Phosphinoxid bzw. eines Phosphoroxidchlorids. Der Einfluß der P-, C- und N-ständigen Substituenten auf die Zerfallsgeschwindigkeit wird diskutiert. Triäthylamin spaltet aus 3 Chlorwasserstoff ab; es entstehen Dimere 4 der 1,3,4,2λ5-Oxadiazaphosphole.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080315
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 180
    Electronic Resource
    Electronic Resource
    Vier Synthesewege zu (2-Pyrimidinylamino)-n-alkansäuren (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 862-874 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four Routes for the Synthesis of (2-Pyrimidinylamino)-n-alkanoic AcidsNucleotide analogues of amino acids with variously substituted 2-pyrimidinyl side chains are available by four synthetic routes. 1) The cyclocondensation of 2-alkyl-3-aminoacroleins (4) with amino acids containing guanidino functions (5b) gives Nδ-(5-alkyl-2-pyrimidinyl)ornithine derivatives (7). 2) Cyclocondensations of 1,3-diketones of (9) with C-(guanidino)amino acids or N-(amidino)amino acids (5a-d) yield (4,6-dialkyl-2-pyrimidinylamino)-n-alkanoic acids (10). 3) (4-Alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)-n-alkanoic acids (13) are obtained by way of cyclocondensation of ethyl acetoacetate (12) with 5a-c. 4) The nucleophilic substitution of 2-ethylthio-6-oxo-1,6-dihydropyrimidines (14, 17) by mono- and diamino acids (15) yields (5-alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)- and (4-alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)-n-alkanoic acids (16, 18).
    Notes: Nucleotid-analoge Aminosäuren mit verschieden substituierten 2-Pyrimidinyl-Seitenketten sind auf vier Wegen zugänglich: Die Cyclokondensation von 2-Alkyl-3-aminoacroleinen (4) mit Aminosäuren mit Guanidinofunktion (5b) führt zu Nδ-(5-Alkyl-2-pyrimidinyl)ornithin-Derivaten (7). Cyclokondensationen von 1,3-Diketonen (9) mit C-(Guanidino)aminosäuren bzw. N-(Amidino)aminosäuren (5a-d) liefern (4,6-Dialkyl-2-pyrimidinyiamino)-n-alkansäuren (10). Durch Cyclokondensationen von Acetessigester (12) mit 5a-c sind (4-Alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)-n-alkansäuren (13) darstellbar. Aus 2-Äthylthio-6-oxo-1,6-dihydropyrimidinen (14, 17) lassen sich durch nucleophile Substitution mit Mono- und Diaminosäuren (15) (5-Alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)- sowie (4-Alkyl-6-oxo-1,6-dihydro-2-pyrimidinylamino)-n-alkansäuren (16, 18) erhalten.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080319
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 181
    Electronic Resource
    Electronic Resource
    Photoelektronenspektren und Moleküleigenschaften, XLV. Schwefelsäure-Derivate : Alkyl-, Vinyl- und Arylsulfone, Alkylsulfoimide und Sulfurylhalogenide (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 897-913 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectra and Molecular Properties, XLV. Sulfuric Acid Derivatives : Alkyl, /Vinyl, and Aryl Sulfones, S,S-Dialkylsulfoimides and Sulfuryl HalidesThe photoelectron (PE) spectra of the following sulfuric acid derivatives are discussed comparatively using qualitative MO models supported by modified CNDO calculations. The substituent effects  -  including the isoelectronic exchange S=O → S=NH and structural modifications  -  can be summarized in correlation diagrams and rationalized as perturbations of the ++ group.
    Notes: Die Photoelektronen(PE)-Spektren der folgenden Schwefelsäure-Derivate werden mit qualitativen MO-Modellen, gestützt auf modifizierte CNDO-Rechnungen, vergleichend diskutiert. Die Substituenten-Effekte - den isoelektronischen Austausch S=O → S=NH und Strukturänderungen eingeschlossen  -  lassen sich in Korrelationsdiagrammen zusammenfassen und als Störungen der -Gruppe betrachten.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080322
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 182
    Electronic Resource
    Electronic Resource
    Gekoppelte Elektrodenreaktionen, II. Benzonitril als Reaktionsmedium für anodisch erzeugte Carbeniumionen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 967-972 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Coupled Electrode Reaction, II. Benzonitrile as a Reaction Medium for Anodically Generated Carbenium IonsBy electrolysis of pivalic acid and isobutyric acid in benzonitrile/isopropyl alcohol in undivided cells N alkylated benzylamines and N,N′-diisopropyl-1,2- diphenylethylenediamine are isolated in a total yield up to 60 percent of the condensed reaction products. The reaction path is explained by anodically generated carbenium ions which react with bezonitrile forming nitrilium ions 3. These are reduced at the cathode (6, 8) or are hydrodimerized (7). The details and the formation of by-products are discussed.
    Notes: Bei der Elektrolyse von Pivalinsäure und Isobuttersäure in Benzonitril/Isopropylalkohol in ungeteilten Zellen werden in einer Gesamtausbeute bis zu 60% der kondensierten Reaktions-produkte N-alkylierte Benzylamine und N,N′-Diisopropyl-1,2-dipnhenyläthylendiamin isoliert. Der Reaktionsverlauf wird über anodisch erzeugte Carbeniumionen erklärt, die mit Benzonitril zu Nitriliumionen 3reagieren. Diese werden an der Kathode reduziert (6, 8) oder hydrodimerisiert (7). Die Einzelheiten und die Bildung von Nebenprodukten werden besprochen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080329
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 183
    Electronic Resource
    Electronic Resource
    Masthead (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975) 
    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.19751080401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 184
    Electronic Resource
    Electronic Resource
    Natürlich vorkommende Terpen-Derivate, XLIII. Neue Sesquiterpenlactone aus Athanasia-Arten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 357-361 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, XLIII. New Sequiterpene Lactones from Athanasia SpeciesThe investigation of four further Athanasia species shows that furansesquiterpenes of the type 1-4 are characteristic for this genus. Besides known compounds five new sesquiterpene lactones have been isolated and their structures elucidated (6, 7, 9, 10 and 13). The close biogenetic relationships of these lactones to already known sesquiterpenes are apparent.
    Notes: Die Untersuchung von vier weiteren Athanasia-Arten zeigt, daß Furansesquiterpene vom Typ 1-4 für diese Gattung charakteristisch sind. Neben bereits bekannten Verbindungen werden fünf neue Sesquiterpenlactone isoliert und in ihrer Konstitution aufgeklärt (6, 7, 9, 10 und 13). Die engen biogenetischen Beziehungen dieser Lactone zu bereits bekannten Sesquiterpenen sind offensichtlich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080144
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 185
    Electronic Resource
    Electronic Resource
    Hydrogenolyse kleiner Kohlenstoffringe, II. Über die Hydrierung von Basketan- und Snoutanderivaten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 337-356 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrogenolysis of Small Cycloalkanes, II. hydrogenation Basketane- and Snoutane-Derivativescis- and both trans-dimethyl twistane-4,5-dicarboxylates (9 and 11, 13) are formed via the dihydro intermediates 4-7 by hydrogenation of cis- and trans-dimethyl basketane-9,10-dicarboxylates (1 and 3) over Pd/C under normal conditions. During the uptake of the first mole-equivalent of hydrogen all the basketane derivatives were rearranged to snoutane derivatives (22 and 24) to some extent. The second C—C bond is cleaved on that side of the basketane skeleton, which is opposite to the first hydrogenated one. cis- and trans-dimethyl snoutane-9,10-dicarboxylates (22 and 24) were hydrogenated under the same conditions but more slowly via the dihydro derivatives (25, 27 and 29, 31) to yield cis- and trans-dimethyl isotwistanedicarboxylates (33 and 35). In snoutane derivatives the second cyclopropane ring is cleaved exclusively from the same side of the molecule as the first one. This is shown by separate hydrogenations of dihydro snoutane derivatives (27, 37 and 38). Hydrogenation of basketene (21) provides a mixture containing 70-75% of twistane (17) and 25-30% of isotwistane (39). The reasons for the different ways of hydrogenation in both systems are discussed. The configurations of all dihydro intermediates and endproducts have been established.
    Notes: cis- und trans-Basketan-9,10-dicarbonsäure-dimethylester (1 und 3) werden unter Normal-bedingungen mit Pd/C in Methanol über die isomeren Dihydrozwischenstufen (4-7) zu cis- und den beiden trans-Twistan-4,5-dicarbonsäure-dimethylestern (9 und 11, 13) hydriert. Bei der Hydrogenolyse der ersten C—C-Bindung erfolgt teilweise Umlagerung zu Snoutanderivaten (22 und 24). Die Öffnung der zweiten Bindung am Basketangerüst geschieht ausschließlich an der zur ersten hydrierten Bindung gegenüberliegenden Molekülseite. cis- und trans-Snoutan-9,10-dicarbonsäure-dimethylester (22 und 24) reagieren unter den gleichen Bedingungen ebenfalls, aber langsamer, über die Zwischenstufen (25, 27 und 29, 31) zu cis- und trans-Isotwistan-dicarbonsäure-dimethylester (33 und 35). An den getrennt untersuchten Zwischenstufen 27, 37 und 38 wird gezeigt, daß im Snoutangerüst beide Cyclopropanringe ausschließlich von der gleichen Molekülseite angegriffen werden. Aus Basketen (21) erhält man bei der Hydrierung ein Gemisch von 70-75% Twistan (17) und 25-30% Isotwistan (39). Die Ursachen für den verschiedenen Hydrierungsverlauf in beiden Systemen werden erörtert, und die Konfiguration aller Zwischenstufen und Endprodukte wird aufgeklärt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080143
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 186
    Electronic Resource
    Electronic Resource
    Die Synthese von 5α-Stigmasta-22,25-dien-3β-ol, 5α-Stigmast-22-en-3β-ol und 5α-Stigmastan-3β-ol und ihren 24-Epimeren (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1101-1110 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Synthesis of 5α-Stigmasta-22,25-dien-3β-ol, 5α-Stigmast-22-en-3β-ol und 5α-Stigmastan-3β-ol and their 24-EpimersThe synthesis of the title compounds from butynylcarbinols 5 with 1-dimethylamino-1-methoxy-1-propene in a Claisen rearrangement via the amides 7 is described. An effective preparation of the starting materials is given and the data of the products are compared with those from natural sterols.
    Notes: Die Synthese der Titelverbindungen aus den Butinylcarbinolen 5 mit 1-Dimethylamino-1-methoxy-1-propen in einer Claisen-Umlagerung über die Amide 7 wird beschrieben. Eine effektive Darstellung der Ausgangsverbindungen wird angegeben, und die Daten der Produkte werden mit den aus Naturstoffen gewonnenen verglichen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080415
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 187
    Electronic Resource
    Electronic Resource
    Aromatische Diazoniumsalze, VI; Nitroso-acyl-amine und Diazoester, XIV Eine neue Reaktionsweise des N-Nitrosoacetanilids (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1027-1035 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Diazonium, VI; Nitrosoacylamines and Diazoesters, XIV A New Reaction Mode of N-NitrosoacetanilideA side reaction in the decomposition on N-nitrosoacetanilide in ethanol/potassium acetate, which has been described to produce a salt K[C8H8N3O3]6), was reinvestigated. It is probale that this compound is formed by a free radical addition of NO to the nitroso group of N-nitrosoacetanilide and subsequent reduction. The potassium salt and the corresponding silver salt are considered to be derived from N-nitroso-N-(N-phenylacetamido)hydroxylamine (7) in agreement with spectroscopic data. Dynamic n. m. r. allows to measure a rotation process with ΔG≠ = 16.0 and ΔG° = 0.6 kcal/mole.
    Notes: Eine früher beschriebene6) Nebenreaktion beim Zerfall des N-Nitrosoacetanilids in Äthanol/Kaliumacetat, die zur Bildung eines Salzes K[C8H8N3O3] führte, wurde erneut untersucht. Es ist wahrscheinlich, daß diese Verbindung durch radikalische Addition von NO an die Nitrosogruppe des N-Nitrosoacetanilids und anschließende Reduktion entsteht. Das Kaliumsalz und ein entsprechendes Silbersalz werden in Übereinstimmung mit spektroskopischen Daten als Salze des N-Nitroso-N-(N-phenylacetamido)hydroxylamins (7) formuliert. Die NMR-Linienformanalyse gestattet die Messung einer Rotationsschwelle mit ΔG≠ = 16.0 und ΔG° = 0.6 kcal/ mol.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 188
    Electronic Resource
    Electronic Resource
    Reaktionen mit Derivaten aus der (CH)8CH2-Reihe; der dirigierende Einfluß von Substituenten bei der Photolyse einiger cis-3a, 7a-Dihydroindene (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1052-1073 
    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 Derivatives of the (CH)8CH2-Family; the Governing Influence of Substituents on the Photolysis of Several cis3a,7a-DihydroindenesOn photochemical or thermal activation the tricyclo[4.3.0.02,5]nonadienes 10, 12, 14a, b, 16 are transformed to the cis-dihydroindenes 11, 13, 15a, b, 17. As determined by the reaction halflives at 120 and 153°C, respectively, the thermal stability of the starting compounds decreases in the order 14b 〉 14a ⋍ 16 〉 12 〉 10; steric reasons are discussed as a possible explanation for this sequence. Cycloaddition reaction of 11, 13, 15a, b, (17 is unreactive) with maleic anhydride and 4-phenyl-1,2,4-triazoline-3,5-dione, respectively, yield the adducts 21(21′)a, b, 22a, b, 24 and 25 for which the endo-configuration of the carbocyclic five-membered ring with respect to the C-8/C-9 double bond is unambigously proven at least in the case of 22a, b by formation of the cagephotoproducts 23a, b. Irradiation of the dihydroindenes involves different pathways: while excitation of 13 leads back to the tricyclic diene 12 the tetraesters 15a, b are converted to the intramolecular cyclization products 28a, b, and the diphenyl-compound 17 undergoes phenyl migration affording the di-π-methane isomer 30; all reactions proceed in a specific manner and only under direct irradiation conditions.
    Notes: Die Tricyclo[4.3.0.02,5]nonadiene 10, 12, 14a, b, 16 wandeln sich bei photochemischer oder thermischer Aktivierung in die cis-Dihydroindene 11, 13, 15a, b, 17 um. Aus den bei 120 bzw. 153°C ermittelten Halbwertszeiten der Isomerisierungen ergibt sich für die Ausgangsverbindungen eine in der Reihenfolge 14b 〉 14a ⋍ 16 〉 12 〉 10 abnehmende thermische Stabilität; als Ursache hierfür werden sterische Faktoren diskutiert. Cycloadditonen von Maleinsäureanhydrid bzw. 4-Phenyl-1.2.4-triazolin-3.5-dion an 11, 13, 15a, b (17 reagiert nicht) liefern die Addukte 21(21′)a,b, 22a,b,24 und 25 für welche die endo-Anordnung des carbocyclischen Fünfrings bezüglich der C-8/C-9-Doppelbindung zumindest für 22,a b duch die photochemische Bildung der Käfigverbindungen 23a, b, gesichert ist. Ber der Belichtung der Dihydroindene ist das Ergebnis sehr unterschiedlich: während der Diester 13 den Tricyclus 12 zurückbildet, werden die Tetraester 15a, b in einer intramolekularen Cyclisierung zu 28a, b und das Diphenyl-Substrat 17 in einer Di-π-Methan-Umlagerung zu 30 umgewandelt; alle Reaktionen verlaufen spezifisch und nur unter direkten Bestrahlungsbedingungen.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080411
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 189
    Electronic Resource
    Electronic Resource
    Neue Derivate des Fluorenon-hydrazons (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1138-1141 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Fluorenone Hydrazone DerivativesThe triaminoguanidines 3a and b and N-[bis(methylthio)methylene]-N′-fluorenylidenehydrazine (4) have been synthesized. Compound 4 reacted with amines and hydrazine hydrate to give S-methylisothioureas (5), aminoguanidines (6), and triaminoguanidines (7), respectively.
    Notes: Es wurden die Triaminoguanidine 3a und b sowie das N-[Bis(methylthio)methylen]-N′-fluorenylidenhydrazin (4) synthetisiert. Die Reaktion von 4 mit Aminen bzw. Hydrazinhydrat führte in die Reihe der S-Methylisothioharnstoffe (5), Aminoguanidine (6) und Triaminoguanidine (7).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080420
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 190
    Electronic Resource
    Electronic Resource
    Umsetzungen N-substituierter Amidine mit Heterokumulenen, V. Umsetzungen mit Isothiocyanaten und Isocyanaten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1142-1155 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of N-Substituted Amidines with Heterocumulenes, V. Reactions with Isothiocyanates and IsocyanatesN1, N2-Dialkyl-substituted amidines (e.g. 1) react with methyl isothiocyanate at room temperature to give thiocarbamoylamidines (e. g. 6) without an intramolecular hydrogen bond, whereas at elevated temperatures cyclic 1: 2-adducts (30-32) are formed. Aromatic isothiocyanates yield exchange products (34-37), whereas cyclic amidines (15-17) yield thiocarbamoylamidines (20, 26, 27) with intramolecular NH…N-bridges because of lower steric hindrance around R2. - The reaction between N1, N2-dialkyl-substituted amidines and isocyanates in the presence of larger groups R2 or strongly electron-withdrawing groups R5 yields only instable carbamoylamidines. The zwitter-ion intermediate (4) then undergoes an intramolecular reaction to give exchange products or adds a dipolarophile to yield 1,3,5-triazacyclohexane derivatives (46, 47, 51-54). These products are not formed when attack on C-2 is rendered considerably more difficult by R2 (tert-C4H9) (43, 56) or when R2=CH3 favours the formation of a very strong hydrogen bond (55).
    Notes: N1, N2-Dialkylsubstituierte Amidine (z. B. 1) reagieren mit Methylisothiocyanat bei Raumtemperatur zu Thiocarbamoylamidinen ohne intramolekulare Wasserstoffbrücke (z. B. 6), bei höheren Temperaturen zu cyclischen 1:2-Addukten (30-32). Aromatische Isothiocyanate führen zu Austauschprodukten (34-37), cyclische Amidine (15-17) geben dagegen Thiocarbamoylamidine (20, 26, 27) mit intramolekularen NH…N-Brücken infolge sterischer Entlastung um R2.  -  Die Umsetzung N1, N2-dialkylsubstituierter Amidine mit Isocyanaten führt in Gegenwart größerer Reste R2 oder stark elektronenabziehender Substituenten R5 nur zu instabilen Carbamoylamidinen. Das intermediär entstehende Zwitterion (4) reagiert dann intramolekular zu Austauschprodukten oder unter Anlagerung eines Dipolarophils zu 1,3,5-Triazacyclohexanderivaten (46, 47, 51-54). Diese Produkte werden nicht gebildet, wenn R2 (tert-C4H9) den Angriff an C-2 beträchtlich erschwert (43, 56) oder R2=CH3 die Ausbildung einer besonders festen Wasserstoffbrücke begünstigt (55).
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080421
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 191
    Electronic Resource
    Electronic Resource
    Lichtreaktionen mit Carbonsäurederivaten, IX. Abfangversuche mit photochemisch erzeugtem monoatomarem und diatomarem Schwefel. Schwefeladdition an 1,2-Dimethylencyclohexan. - Synthese von 1,4,5,6,7,8-Hexahydrobenzo[d][1,2]dithiin und 1,3,4,5,6,7-Hexahydrobenzo[c]thiophen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 630-639 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoreactions with Carbonic Acid Derivatives, IX. Experiments on the Capture of Photochemically Produced Monoatomic and diatomic sulfur-Sulfur Addition on 1,2-Dimethylenecyclohexane.-Synthesis of 1,4,5,6,7,8-Hexahydrobenzo-[d][1,2]dithiin and 1,3,5,6,7-Hexahydrobenzo[c]thiopheneIn addition to cis- and trans-2,3-diethoxy-2-butene (3) small amounts of 2,3-diethoxy-1-butene (6), 2,3-diethoxy-1,3-butadiene (7) and 1-ethoxy-1-ethanethiol (5) were found in the irradiation product of O-ethyl thioacetate. The produced sulfur adds to a slight extent to 1,2-Dimethylenecyclohexane giving 1,4,5,6,7,8-hexahydrobenzo[d][1,2]dithiin (8), 1,3,4,5,6,7-hexahydrobenzo-[c]thiophene (9) and 4,5,6,7-tetrahydrobenzo[c]thiophene (10). For definite identification of the reaction products 8, 9 and 10 were synthesized.
    Notes: Im Bestrahlungsprodukt von Thionessigsäure-äthylester (1) wurden neben cis- und trans-2,3-Diäthoxy-2-buten (3) in geringen Mengen noch 2,3-Diäthoxy-1-buten (6); 2,3-Diäthoxy-1,3-butadien (7) und α-Mercaptodiäthyläther (5) nachgewiesen. - Der gebildete Schwefel addiert sich in geringem Ausmaß an 1,2-Dimethylencyclohexan unter Bildung von 1,4,5,6,7,8-Hexahydrobenzo[d][1,2]dithiin (8), 1,3,4,5,6,7-Hexahydrobenzo[c]thiophen (9) und 4,5,6,7-Tetrahydrobenzo[c]thiophen (10). Zur sicheren Identifizierung der Reaktionsprodukte wurden 8, 9 und 10 synthetisiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080229
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 192
    Electronic Resource
    Electronic Resource
    Acylgruppenwanderung, V. Kinetische Daten der Acylgruppenwanderung von 2-Benzoyl-3-indenyl-acetat und 3-Benzoyl-2-indenyl-acetat (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 683-692 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acyl Group Migration, V. Kinetic Parameters of Acyl Group Migration in 2-Benzoyl-3-indeny Acetate and 3-Benzoyl-2-indenyl Acetate2-Acyl-1-indanones 6 and 8, obtained by ester condensation from 1-indanone, react with acetyl chloride to form the corresponding enolesters 7 and 9. In solution the Z-isomers, (Z)-2-(1-acetoxyethylidene)-1-indanone (7B) and (Z)-2-(1-acetoxybenzylidene)-1-indanone (9aB) as well as 9bB and 9cB show a rapid equilibrium by acetyl group migration with the 2-acyl-3-indenyl acetates 7C and 9C:7B ⇄ 7C, 9B ⇄ 9C. The isomerisation of the semicyclic C=C double bond 7B ⇄ 7A or 9B ⇄ 9A is catalysed photochemically. The kinetic parameters of the acetyl group migration have been determined by n. m. r. line-shape analysis for the isomeric enol esters 2-benzoyl-3-indenyl acetate (9aC) and 3-benzoyl-2-indenyl acetate (10C).
    Notes: Die durch Esterkondensation aus 1-Indanon erhaltenen 2-Acyl-1-indanone 6 und 8 werden mit Acetylchlorid in die zugehörigen Enolester 7 und 9 übergeführt. Die Z-Isomeren, (Z)-2-(1-Acetoxyäthyliden)-1-indanon (7B) und (Z)-2-(1-Acetoxybenzyliden)-1-indanon (9aB) sowie 9bB und 9cB liegen in Lösung durch schnelle Acetylgruppenwanderung im Gleich-gewicht mit den 2-Acyl-3-indenyl-acetaten 7C und 9C vor: 7B ⇄ 7C bzw. 9B ⇄ 9C. Die Isomerisierung der semicyclischen C=C-Doppelbindung 7B ⇄ 7A bzw. 9B ⇄ 9A wird photochemisch erreicht. Durch eine NMR-Linienformanalyse wurden die kinetischen Daten der Acetylgruppenwanderung am Beispiel der beiden isomeren Enolester 2-Benzoyl-3-indenylacetat (9a C) und 3-Benzoyl-2-indenyl-acetat (10 C) ermittelt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080234
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 193
    Electronic Resource
    Electronic Resource
    Notiz über Donor-Akzeptor-komplexe zwischen Organylhalogenboranen und Diorganylchalkogenen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 724-726 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080238
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 194
    Electronic Resource
    Electronic Resource
    Abfangreaktionen kurzlebiger Radikale, XII Über die radikalische substitution am Schwefel: Induzierter Zerfall von (Thio)Carbonyldisulfiden (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1339-1345 
    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, XII. Free Radical Substitution at the Sulfur Atom: The Induced Degradation of (Thio)Carbonyl DisulfidesDibenzoyl, diacetyl, bis(thiobenzoyl) disulfide (1, 2, 7), and benzoyl 4-tolyl disulfide (11) are degradated by hydrides R3SnH at 60°C about 103 times faster than in the spontaneous degradation. The products and following reactions have been established. In all cases, SH2 mechanisms are found, with attack of stannyl radicals at the (acyl bound) sulfur atom. In the case of 1, 2 and 11, ΔHspont.≠ is 35 or 34 ± 2 kcal/mole at 150°C.
    Notes: Dibenzoyl-, Diacetyl-, Bis(thiobenzoyl)disulfid (1, 2, 7) und Benzoyl(4-tolyl)disulfid (11) werden durch Hydride R3SnH bei 60°C im Verhältnis zum Spontanzerfall etwa um den Faktor 103 rascher abgebaut. Produkte und Folgereaktionen werden sichergestellt. Es liegen jeweils SH2-Mechanismen mit Angriff von Stannyl-Radikalen am (acylseitigen) Schwefel vor. Bei 1, 2 und 11 ist ΔH spont.≠ = 35 bzw. 34 ± 2 kcal/mol bei 150°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080439
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 195
    Electronic Resource
    Electronic Resource
    Kristall- und Molekülstruktur von Bis(triphenylphosphin)iminium-tetracarbonylpropylferrat,[{(C6H5)3P}2N] [Fe(CO)4C3H7] (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1373-1383 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structure of Bis(triphenylphosphine)iminium Tetracarbonylpropyliron, [{(C6H5)3P}2 N] [Fe(Co)4C3H7]The crystal and molecular structure of the title compound has been determined by X-ray diffraction methods. The yellow salt crystallizes in the monoclinic space group C2/c with 8 molecules per cell. The structure was solved by conventional methods (agreement factor R1 = 0.07). Within the trigonal bipyramidal coordination polyhedron of the [Fe(CO)4C3H7] anion, the propyl group occupies an axial position. The bond length Fe-Cpropyl is 220(2) pm, the Fe-Cco distances are equal within experimental error (mean value 175(2) pm). The distances within the [{(C6H5)3P}2N] cation are similar to those found for the same ion in different crystalline salts. However, unexpectedly, an hitherto unknown new conformation is observed for the cation.
    Notes: Die Kristall- und Molekülstruktur der Titelverbindung wurde durch Röntgenbeugungsanalyse bestimmt. Das gelbe Salz kristallisiert in der monoklinen Raumgruppe C2/c mit 8 Molekülen in der Elementarzelle. Die Lösung der Struktur erfolgte mit konventionellen Methoden (Übereinstimmungsfaktor R1 = 0.07). Im [Fe(CO)4C3H7]-Anion besetzt die Propylgruppe eine axiale Position des trigonal-bipyramidalen Koordinationspolyeders um das Eisen. Die Fe-CPropyl-Bindungslänge beträgt 220(2) pm, die Fe-Cco-Abstände sind innerhalb der Fehlergrenzen gleich lang (Mittelwert: 175(2) pm). Die Abstände innerhalb des [{(C6H5)3P}2N]-Kations unterscheiden sich nicht von denen, die für das gleiche Ion in verschiedenen kristallinen Salzen gefunden wurden; unerwarteterweise liegt das Kation jedoch in einer neuen, bislang unbekannten Konformation vor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 196
    Electronic Resource
    Electronic Resource
    Reaktionen mit Cyclobutendionen, XXXVII. Umsetzungen des (2,5-Dimethoxyphenyl)phenyl- und des Diphenylcyclobutendions mit Diazoalkanen. Ein Beitrag zur Isomerie der möglichen 1-Pyrazoline (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1413-1420 
    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 Cyclobutenediones, XXXVII. Reactions of (2,5-Dimethoxyphenyl)phenyl-and Diphenylcyclobutenedione with Diazoalkanes. A Contribution to the Study of Isomerism of Possible 1-Pyrazolines(2,5-dimethoxyphenyl)phenylcyclobutenedione (7) reacts with diazomethane to give only 3a-(2,5-Dimethoxyphenyl)-4-methoxy-6-oxo-6a-phenyl-3,3a,6,6a-tetrahydrocyclopentapyrazole (8a). In glacial acetic acid 8a isomerizes to the 2-pyrazoline 9a. Diphenylcyclobutenedione (1) reacts with diazoethane to yield the diastereomeric 1-pyrazolines 10 and 11. These two compounds isomerize in glacial acetic acid to form the same 2-pyrazoline 12 and react with acetyl chloride to give the same N-acetyl derivative 13. In xylene 10 reacts to form the 4-ethoxy-3,6-dimethyl-1,5-diphenylbicyclo[3.1.0]hex-3-en-2-one (14), while in boiling tetrahydronaphthalene 10 gives two isomeric phenols 16 and 18.
    Notes: (2,5-Dimethoxyphenyl)phenylcyclobutendion (7) reagiert mit Diazomethan in Benzol ausschließlich zu 3a-(2,5-Dimethoxyphenyl)-4-methoxy-6-oxo-6a-phenyl-3,3a,6,6a-tetrahydrocyclopentapyrazol (8a). Dieses kann in Eisessig zum 2-Pyrazolin 9a umgelagert werden. Diphenylcyclobutendion (1) reagiert mit Diazoäthan zu zwei diastereomeren 1-Pyrazolinen 10 und 11. Beide ergeben in Eisessig das gleiche 2-Pyrazolin 12 sowie mit Acetylchlorid das N-Acetyl-Derivat 13. In Xylol wird 10 in das 4-Äthoxy-3,6-dimethyl-1,5-diphenylbicyclo[3.1.0]hex-3-en-2-on (14) und in Tetralin in die isomeren Phenole 16 und 18 übergeführt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080508
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 197
    Electronic Resource
    Electronic Resource
    Über Phosphazene, LII. Disproportionierung von PCl3 und CH3PCl2 bei der Cyclokondensation mit einem Amino-di(phosphazen) (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1454-1459 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphazenes, LII. Redox Disproportionation of PCl3 and CH3PCl2 during the condensation with an Aminodi(phosphazene)In a condensation and concomitant redox disproportionation CH3PCl2 and PCl3 convert the NPNPN chain of bis(aminodiphenylphosphorus) nitride chloride 6 into six-membered rings. 2-Chloro-2-methylcyclotri(phosphazene) 12 and spirobi[cyclotri(phosphaza)]pentaene 8 (as hydrochloride 7, X = Cl) are obtained, respectively. An intermediate of the spirophosphazene formation is the chloro-hydrido-λ5- or the λ3-phosphazene 4, X = Cl, or 5, respectively. It is of importance, that the second rings starts to form before the spiro center is oxidized. Competing oxidation by CCl4 leads to the gem. dichlorophosphazene 13, which enters no further reaction.
    Notes: Unter gleichzeitiger Redoxdisproportionierung schließen CH3PCl2 und PCl3 die NPNPN-Kette von Bis(aminodiphenylphosphor)nitridchlorid 6 zum Sechsring. Es entsteht das 2-Chlor-2-methyl-cyclotri(Phosphazen) 12 bzw. das Spirobi[cyclotri(phosphaza)]pentaen 8 (als Hydrochlorid 7, X = Cl). Zwischenstufe der Spirophosphazen-Bildung ist das Chlor-hydrido-λ5-oder das λ3-Phosphazen 4, X = Cl, bzw. 5. Wesentlich ist, daß die Angliederung des zweiten Rings noch vor der Oxidation des Spirozentrums eingeleitet wird. Die konkurrierende Oxidation mit CCl4 führt zum gem. Dichlorphosphazen 13, das nicht mehr weiterreagiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080513
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 198
    Electronic Resource
    Electronic Resource
    Gehinderte Ligandbewegung in Übergangsmetallkomplexen, IV. 13C-NMR-Studien an Tricarbonyl-η6-cyclopolyen-Komplexen der Elemente der VI. Nebengruppe (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1502-1510 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hindered Ligand motion in Transition Metal Complexes, IV 13C N.M.R. Studies on Tricarbonyl-η6 -cyclopolyene complexes of the VIB ElementsThe 13C n.m.r. spectra of some tricarbonyl-n6-cyclopolyene complexes of the VIB elements with the cyclopolyenes 1,3,5-cycloheptatriene, 1,3,5-cyclooctatriene, and 1,3,5,7-cyclooctatetraene are reported. Two novel ligand movements have been detected in this group of half-sandwich complexes: 1. A hindered rotation of the cyclopolyene ligands around the prolonged threefold axis of the tricarbonylmetal groups with free energies of activation from 11.3 to 12.7 ± 0.3 kcal/mole. 2. The 1,3,5-cyclooctatriene ligand in C8H10Cr(CO)3 is frozen at - 120°C into a chiral conformation. The enantiomers can be interconverted over an energy barrier of 8.3 ± 0.1 kcal/mole.
    Notes: Die 13C-NMR-Spektren einiger Tricarbonyl-η6-cyclopolyen-Komplexe der Elemente der VI. Nebengruppe mit den cyclopolyenen 1,3,5-Cycloheptatrien, 1,3,5-Cyclooctatrien und 1,3,5,7-Cyclooctatetraen werden beschrieben. Zwei neuartige Ligandbewegungen konnten an dieser Gruppe von Halbsandwichkomplexen nachgewiesen werden: 1. Eine gehinderte Rotation der Cyclopolyenliganden um die verlängerte dreizählige Achse der Tricarbonylmetallgruppen mit freien Aktivierungsenthalpien von 11.3 bis 12.7 ± 0.3 kcal/mol. 2. Der.1,3,5-Cyclooctatrienligand in C8H10Cr(CO)3 ist bei - 120°C in einer chiralen Konformation eingefroren. Die beiden Enantiomeren können über eine Energiebarriere von 8.3 ± 0.1 kcal/mol ineinander übergeführt werden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080518
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 199
    Electronic Resource
    Electronic Resource
    Heterocyclisierungen, XV. Über die Reaktion von 2,3,3-Trimethylindoleninen und 1-Methyl-3,4-dihydroisochinolin mit Acyliso(thio)cyanaten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1541-1547 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclizations, XV. The Reaction of 2,3,3-Trimethylindolenines and 1-Methyl-3,4-dihydroisoquinoline with Acyliso(thio)cyanates5-Methoxy- and 5-nitro-2,3,3-trimethylindolenines (7a, b) react with dielectrophilic iso(thio)cyanates to give the pyrimido[3,4-a]indoles 14, 15. Furthermore, 7a affords a dicarbamoylmethylene derivative 16, which undergoes cyclization to the pyrimidinylidene indole 17. 1-Methyl-3,4-dihydroisoquinoline (21) condenses with dielectrophilic iso(thio)cyanates to the pyrimido[6,1-a]isoquino-lines 24, hitherto unknown in this stage of saturation.
    Notes: 5-Methoxy- und 5-Nitro-2,3,3-trimethylindolenin (7a, b) reagieren mit dielektrophilen Iso(thio)-cyanaten zu den Pyrimido[3,4-a]indolen 14, 15. Darüber hinaus bildet 7a ein Dicarbamoyl-methylenindol 16, das zum Pyrimidinylidenindol 17 cyclisiert. 1-Methyl-3,4-dihydroisochinolin (21) liefert mit dielektrophilen Iso(thio)cyanaten die in der vorliegenden Sättigungsstufe noch nicht beschriebenen Pyrimido[6,1-a]isochinoline 24.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080523
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 200
    Electronic Resource
    Electronic Resource
    Alkylierung von Polyphenolderivaten, III. 2,6-Di-n-alkyl-1,4-benzochinone mit langen Alkylketten (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1570-1579 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylation of Polyphenol Derivatives, III. 2,6-Di-n-alkyl-1,4-benzoquinones with Long Alkyl ChainsThe syntheses of 1,4-benzoquinones 7, 13, and 23, substituted in the 2,6-positions with dodecyl residues, are described. The corresponding phenol ethers were acylated with dodecanoic acid/boron trifluoride and/or metalated and then alkylated with 1-bromododecane. The dialkylated phenol ethers 5, 11, and 20 were demethylated with boron tribromide and dehydrogenated to the corresponding benzoquinones with nitric acid or iron(III) sulfate, respectively.
    Notes: Es wird die Synthese der 2,6-Dodecyl-1,4-benzochinone 7, 13 und 23 beschrieben. Die Einführung der Dodecylreste erfolgte durch Acylierung entsprechender Phenoläther mit Dodecansäure/Bortrifluorid und/oder Metallierung der Phenoläther mit anschließender Alkylierung durch 1-Bromdodecan. Die dialkylierten Phenoläther 5, 11 und 20 wurden mit Bortribromid entmethyliert und mit Salpetersäure bzw. Eisen(III)-sulfat zu den Chinonen dehydriert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080526
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...