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  • 1975-1979  (7,030)
  • Organic Chemistry  (3,423)
  • Chemical Engineering  (1,916)
  • Engineering General  (946)
  • Computational Chemistry and Molecular Modeling  (745)
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  • 101
    Electronic Resource
    Electronic Resource
    Reaktionen von 3-Dimethylamino-2,2-dimethyl-2H-azirin mit. NH-aciden Heterocyclen; Synthese von 4H-imidazolen (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 768-778 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 3-Dimethylamino-2,2-dimethyl-2H-azirine with NH-Acidic Heterocycles; Synthesis of 4H-ImidazolesIn this paper, reactions of 3-dimethylamino-2,2-dimethyl-2H-azirine (1) with heterocyclic compounds containing the structure unit CO—NH—CO—NH are described. 5,5-Diethylbarbituric acid (5) reacts with 1 in refluxing 2-propanol to give the 4H-imidazole derivative 6 (Scheme 2) in 80% yield. The structure of 6 has been established by X-ray crystallography. Under similar conditions 1 and isopropyl uracil-6-carboxylate (7) yield the 4H-imidazole 8 (Scheme 3), the structure of which is deduced from spectral data and the degradation reactions shown in Scheme 3. Hydrolysis of 8 with 3N HCl at room temperature leads to the α-ketoester derivative 9, which in refluxing methanol gives dimethyl oxalate and 5-dimethyl-amino-2,4,4-trimethyl-4H-imidazole (10). On hydrolysis the latter is converted to the known 2,4,4-trimethyl-2-imidazolin-5-one (11) [6]. Quinazolin-2,4 (1H, 3H)-dione (12) and imidazolidinetrione (parabanic acid, 14) undergo with 1 a similar reaction to give the 4H-imidazoles 13 and 15, respectively (Schemes 4 and 5).In Scheme 6 two possible mechanisms for the formation of 4H-imidazoles from 1 and heterocycles of type 16 are formulated. The zwitterionic intermediate f corresponds to b in Scheme 1. Instead of dehydration as in the case of the reaction of 1 with phthalohydrazide [3], or ring expansion as with saccharin and cyclic imides [1] [2], f, undergoes ring opening (way A or B). Decarboxylation then leads to the 4H-imidazoles 17.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620314
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  • 102
    Electronic Resource
    Electronic Resource
    Triterpènes de la «mousse de chêne» (Evernia Prunastri (L.) ACH.). 5e Communicatione Communication [5]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 807-810 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triterpenoids from ‘Oakmoss’ (Evernia Prunastri (L.) ACH.)Seven triterpenoids have been isolated from ‘oakmoss’ (Evernia Prunastri (L.) ACH.) extracts by column chromatography and identified as friedelin (1), taraxerol (2), 29-nor-21 α-hopan-3,22-dione (3), moretenone (4), ursolic acid (5), lupeol (6) and lanosterol (7).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620316
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  • 103
    Electronic Resource
    Electronic Resource
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150201
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  • 104
    Electronic Resource
    Electronic Resource
    Use of the overlap multipole expansion for approximating molecular electrostatic potentials (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 121-129 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular electrostatic potentials computed by the overlap-multipole-expansion procedure (OMTP) are compared to exact electrostatic potentials computed with the same Gaussian basis set, for different molecular species. It is shown that at distances of the molecule larger than 2.2 Å, the OMTP values compared to those of the exact ones are within an error of 0.5 kcal/mol. This error decreases with increasing distance. For distances below this limit the OMTP potentials may be used as a first indication of the trends of the molecule, provided the values to compare are not too close.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150112
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  • 105
    Electronic Resource
    Electronic Resource
    Quantum chemistry by random walk: H4 square (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 109-120 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The random-walk method of solving the Schrödinger equation is applied to the 1B1g and 1B2g states of the H4 square with side length 2.4 a.u. The results provide an independent check of the accuracy of prior variational calculations for these states. With node structures for the 1B1g state taken from a variational calculation with a single-zeta basis set and taken in the simplest form meeting symmetry requirements, the calculated energies are lower than the expectation value of the energy for the single-zeta basis set but not as low as the expectation value for an optimized-exponent double-zeta basis set with polarization terms. Comparisons of results give no suggestion of a barrier height lower than ∼120 kcal/mol for passage through the square configuration in the exchange reaction H2 + D2 → 2HD. For the 1B2g state with node structure in the simplest form meeting symmetry requirements the calculated energy is ∼65 kcal/mol lower than the expectation value of the energy for variational calculations with a double-zeta basis set.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150111
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  • 106
    Electronic Resource
    Electronic Resource
    First-order properties and the Hellmann-Feynman theorem in the case of a limited CI wave function (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 135-145 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two distinct approaches to the calculation of first-order properties with a limited CI wave function are discussed. One is based on the Hellmann-Feynman theorem and the other on the direct evaluation of the total energy derivative at zero perturbation. Corrections to the Hellmann-Feynman expectation value are given for the CI wave function consisting of a single determinant reference state and all single and double replacements of this. These corrections are the extended Brillouin matrix elements and involve interactions between the zeroth-order wave function and triply substituted configurations. The usefulness of these matrix elements for the generation of MC SCF orbitals and for the calculation of cluster corrections to the wave function is briefly discussed. The formulas for the Brillouin matrix elements expressed in terms of one- and two-electron integrals have been automatically generated using the syntax of the algebraic program SCHOONSCHIP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150202
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  • 107
    Electronic Resource
    Electronic Resource
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150301
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  • 108
    Electronic Resource
    Electronic Resource
    Formal theory of effective π-electron hamiltoniansWork carried out under the auspices of the United States Department of Energy. (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 207-242 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We argue that the goal of developing a satisfactory general formalism for the justification of effective π-electron Hamiltonians, as well as for ab initio calculation of their parameters (α, β, and γ), has now been achieved. The need for a fully linked many-body formalism is emphasized; this feature requires a Rayleigh-Schrödinger (RS) type of degenerate perturbation theory. A number of apparently different degenerate RS perturbation formalisms are reviewed. Most of these formalisms are actually identical term-by-term, when their RS expansions are worked out explicitly; the formal relations that prove their complete equivalence are presented and discussed. One of these formalisms, a version developed by the author for related open-shell problems in nuclear physics, is shown to be most convenient for many-body applications. This is owing to the relatively simple and transparent nature of its general algebraic structure, which facilitates partial summation to infinite order. A simple and concise derivation is presented for the algebraic features of this preferred formalism, and its many-body (linked cluster) aspects are briefly discussed. The recent development of a nonperturbative (coupled-cluster) analog of this formalism is also described. Some practical issues are examined, including the choice of orbital basis. Illustrative numerical results are presented, based on the calculations of Iwata and Freed. Several remaining problems are described; these are both qualitative and quantitative in nature, and their resolution will require some detailed calculations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150207
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  • 109
    Electronic Resource
    Electronic Resource
    Colloquium on the structure small molecules adsorbed on surfaces (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 359-359 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150310
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  • 110
    Electronic Resource
    Electronic Resource
    Two-parameter exponential-type basis functions for atomic calculations (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 389-401 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is found that ordinary STOs fall off too fast in the atomic region in many cases. A new type of basis set, which is more adaptable to the rather different requirements of the various atomic orbitals in an atom, is developed. The suggested functional form χ(r) = Nrn-1 exp{-α[(βr + 1)1/2 - 1]} contains the STOs as a limiting case. Calculations on a series of atoms from H to Zn show that the new basis gives better results than STOs for equal basis set size. The necessary integrals do not present any problem to evaluate.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150405
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  • 111
    Electronic Resource
    Electronic Resource
    Valence photoelectron spectrum of CoO. Ab initio calculations of energies and relative intensities within a limited CI framework (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 403-410 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The valence spectrum of CoO has been calculated using the CoO610- cluster, stabilized by an electrostatic field, as a model of bulk CoO. The wave functions were generated using basis sets of better than double-zeta quality. SCF wave functions were obtained for the ground state and for the first ionized state of the cluster. Limited CI calculations were performed using these orbital sets. The lowest states of the ion correspond to the main lines in the spectrum, while higher states can give rise to high-energy satellites to the main lines. The relative intensities of these satellites were estimated in the case of high-energy incident photons.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150406
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  • 112
    Electronic Resource
    Electronic Resource
    Sagamore VI (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 445-445 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150409
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  • 113
    Electronic Resource
    Electronic Resource
    Neon L-shell photoabsorption cross sections from moment theory and finite basis pseudospectra (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 411-421 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudospectra from Gaussian basis set calculations within a frozen-core approximation have been used in a moment analysis to obtain Tchebychev profiles for the photoabsorption process in the valence shell of Ne. The profiles show good agreement with cross sections obtained in equivalent calculations using numerical atomic wave functions and continuum orbitals, particularly when the dipole-velocity form is employed. Variation of the basis sets shows that it is possible to obtain meaningful photoabsorption profiles using 13-15 virtual orbitals to describe the outgoing electron.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150407
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  • 114
    Electronic Resource
    Electronic Resource
    Role of Ca+2 ion in the abortifacient action of prostaglandins. I. Molecular-orbital and conformation-energy calculations of PGF2α (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 481-489 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The paper reports the study of a possible mechanism of Ca+2 activation of prostaglandin PGF2α on the basis of molecular-orbital and conformation-energy calculations. The electronic charges on various atoms of the molecule have been evaluated from the available crystallographic data by the extended Hückel theory (EHT). Conformation energies were calculated for intrinsic torsional rotations around the C11—C12, C7—C8, and C14—C15 bonds. The minimum energy conformation was found to differ from the crystallographic conformation by 9.3 kcal/mol. Some additional local energy minima are also reported within this range. The calculation of the long-range interchain interaction energy between the α and ω chains shows variation with conformation. The binding site for the Ca+2 ion has been estimated on the basis of the molecular electrostatic potentials. Such a binding site was found near the carboxyl group, which agrees with the current chemical thinking. Changes in the electronic charge distribution due to Ca+2 complexation were studied by EHT method using the supramolecular approach. Calcium complexation decreases the conformation energy by 2-3 kcal/mol and has a small effect on the interchain interaction energy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150504
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  • 115
    Electronic Resource
    Electronic Resource
    Nonbonded interactions in membrane-active cyclic biopolymers. III. Analogs of valinomycin (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 491-497 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several analogs of valinomycin have been simulated. These are analogs obtained by changing the configuration of the amino acid and hydroxy acid residues one at a time. Nonbonded interactions have been calculated for three conformations of each analog. The electrostatic and polarization contributions to the energy are conformation selective, whereas the Pauli repulsion is the only component which is isomer selective. For the ring chirality considered here the analog of valinomycin having all the three L-valyl residues replaced by D-valyl residues is predicted to be frozen in a “top open” conformation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150505
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  • 116
    Electronic Resource
    Electronic Resource
    Ab initio study of a purine nucleoside: Adenosine (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 499-510 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ab initio SCF LCAO-MO method is used to compute the main electronic properties of a purine nucleoside, adenosine, in two specific conformational arrangements (3′-endo conformation of the ribose, gt orientation of the extracyclic CH2OH group, anti orientation of the base with respect to the sugar and 3′-endo conformation of the ribose, gg orientation of the extra-cyclic CH2OH group, syn orientation of the base with respect to the sugar). The results are compared with those performed for the isolated component fragments, adenine and 3′-endo riboses.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150506
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  • 117
    Electronic Resource
    Electronic Resource
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150601
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  • 118
    Electronic Resource
    Electronic Resource
    Cyanide-Isocyanide isomerization in the structural isomers of cyanogen isocyanate (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 547-557 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyanide-isocyanide isomerization has been studied with ab initio calculations in an STO-3G basis as applied to NCNCO, NCCNO, NCOCN, and NCONC, and the corresponding isocyanides. Geometry optimization has been performed on these cyanides, their isocyanides, and their hypothetical transition states. The energies of isomerization were calculated to be 42.2, 29.8, 44.6, and 41.4 kcal/mol, respectively, while the energy barriers were found as 84.3, 67.5, 107.9, and 106.8 kcal/mol. Overlap populations and atomic charges were employed to provide simple correlations of the results.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150510
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  • 119
    Electronic Resource
    Electronic Resource
    Configuration-Interaction study of lower excited states of O2: Valence and rydberg characters of the two lowest 3Σu - states (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 533-545 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Configuration-interaction calculations, with an extended basis, are carried out on the ground and lower excited states of O2 and O2+ at and near the equilibrium internuclear distance (R = 2.3 a.u.) of the ground state of O2. Particular attention has been paid to the two lowest 3Σu- states, and the mixing of the valence and Rydberg characters in these states are studied. The lowest 3Σu- state is a Rydberg-type state for R 〈 2.3 a.u., but becomes valence-type for R ≳ 2.3 a.u. The second 3Σu- state, which is 1.6 eV above the lowest 3Σu- at R = 2.3 a.u., changes its character from Rydberg to valence, valence to Rydberg, and then to valence again when R increases from 1.9 to 3.1 a.u. Satisfactory agreement between the calculated and experimental vertical excitation energies is obtained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150509
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  • 120
    Electronic Resource
    Electronic Resource
    Ab initio molecular calculations with pseudopotentials: calculations of double-zeta quality on BeH2, BH3, CH4, and C2H6 (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 559-566 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new form of pseudopotential for applicaiton in ab initio molecular calculations is described. A method for determining pseudopotential parameters is suggested and pseudopotential parameters of double-zeta quality are presented for the first row atoms of the periodic table. The pseudopotential is especially well suited for incorporation into the floating-spherical-Gaussian-orbital (FSGO) method, though it is not restricted to any particular method. Applications of the resulting pseudo-FSGO method to BeH2, BH3, CH4, and C2H6 are presented.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150602
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  • 121
    Electronic Resource
    Electronic Resource
    Ab initio molecular fragment calculations with pseudopotentials: Hydrocarbon calculations of double-zeta quality (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 567-578 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudopotential theory is introduced into the ab initio FSGO molecular fragment method. A theoretical background for the pseudopotential fragment description and a method for large molecule formation is presented. Core-valence electron separation is achieved at both levels of the calculations with the resulting simplification of the molecular calculations. Using pseudopotentials of double-zeta quality a detailed description of pseudopotential molecular fragments CH4 (tetrahedral) and CH3 (planar) is presented. Applications of the pseudo-FSGO molecular fragment method to hydrocaroons are discussed. The results are compared to those of the original FSGO method and experiment.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150603
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  • 122
    Electronic Resource
    Electronic Resource
    Spin-Free configuration-interaction study of molecules using single-parameter alternat molecular orbitals (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 579-588 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure is outlined for a programmable spin-free configuration-interaction (CI) study in molecules using single-parameter alternant molecular orbitals for generating various configurations. The configurations were chosen to form bases for the irreducible representation {2N/2-2, 12S} of the general linear group GL(n). Using a transformation to biorthogonal space the CI matrix elements of a spin-free Hamiltonian were generated. The procedure has been used to obtain the π-electron energies for the 3,1Ag and 3,1Bu states of cis- and trans-butadiene.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150604
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  • 123
    Electronic Resource
    Electronic Resource
    Optical activity of nonrigid molecules (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 713-715 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Longuet-Higgins group is used to obtain an alternative formulation of a criterion for optical activity of nonrigid molecules recently given by Frei and Günthard.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150614
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  • 124
    Electronic Resource
    Electronic Resource
    Solitons, bioenergetics, and the mechanism of muscle contraction (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 5-17 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The properties of exciton and soliton excitations in one-dimensional molecular systems and in α-helical protein molecules are investigated. It is shown that collective excitations - solitons, corresponding to a combination of vibrational excitations in peptide groups and a local deformation of molecules - are possible in α-helical protein molecules. These excitations move along the molecule without energy losses and are perfect energy carriers. A qualitative description of the shortening in the length of muscular fibers is given using the concept of solitons occurring under the hydrolysis of ATP molecules at the ends of thick fibers contained in the sarcomeres of muscular fibers.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160104
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    Are intermediate states responsible for certain specific properties of biological macromolecules? (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 31-42 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new electron structural mechanism is proposed for interpretations in molecular biology, in addition to the already existing theories of Szent-Györgyi (semiconductivity) and Fröhlich (long-range coherence). The hypothetical “intermediate-” or “zigzag states” (ZZS) of solids are investigated by the recursion (transfer matrix) method. The physical reality of the ZZS is discussed up to an SCF DODS-type theory and the necessity of additional less approximate investigations is emphasized. The possible role of ZZS in the explanation of: (i) translation in protein synthesis, (ii) energy and charge transfer processes, as well as (iii) initiation of protein formation is outlined.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160106
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  • 126
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    Organization of phospholipids in biological membranes (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 19-29 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preferred conformations of phospholipids have been predicted through quantum-chemical techniques and classical potential functions. An essential condition for a conformation to exist in a biomembrane is that it should be possible for it to organize in the form of a bilayer. Taking into consideration the conformational flexibility of the polar head group, organization at the lipid-water interface has been considered. The biological implications of such an organization in terms of formation of “hydrophobic channels” is discussed. Quantum-mechanical investigations on the transport phenomenon have shown that the “selectivity” of biological membranes is connected with the “organization.” Calculations of the quantum-mechanical transmission coefficients for different model potential profiles indicate that minor differences in the height of potential barriers in certain regions can lead to significant changes in transmission coefficients. The “directional selectivity” of substrates (differences in transmission coefficients for flow in and out of the cell) can be explained on the basis of differences in membrane organization. These results have some important consequences in the evolutionary process in biological membranes.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160105
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  • 127
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    Conformational changes and excitation energy transfer in myosin-auramine O system (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 43-50 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the myosin-auramine O system 10 or 11 binding sites of auramine O on the rod-like part of myosin were discovered. The myosin fluorescence decreases with an increase in auramine O concentration. This is evidence of the excitation energy transfer from tryptophanyls situated near the binding sites to auramine O. The effective distance of energy transfer is 35 Å. It is suggested that the light meromyosin has binding sites with periodicities of 77-86 Å. Every binding site has a negative charge and hydrophobic locus.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160107
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  • 128
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    What can quantum chemistry contribute to biology? (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 51-56 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The transition from quantum chemistry to quantum biology is discussed, and the contributions that quantum biology can make to the study of biological structure and process are outlined. The need for extensions to the theory to deal with larger systems, to include solvent effects and to account for specificity, are emphasized.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560160108
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  • 129
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    Ab initio molecular fragment calculations with pseudopotentials (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 57-64 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudopotential theory is introduced into the ab initio FSGO molecular fragment method. Pseudopotential molecular fragments using pseudopotentials of double-zeta quality are characterized, and a method of their assembly into larger molecules is presented. Core-valence electron separation is achieved at both levels of the molecular calculations. Heteroatom incorporation into the method is also considered. Applications of the pseudo-FSGO molecular fragment method to hydrocarbons and simple molecular systems containing heteroatoms are discussed. Results are compared to those of the original FSGO method and experiment.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160109
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  • 130
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    Electron pair correlation energies for ZN2+ (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 65-70 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pair energies contributing to the correlation energies of the outer-shell electrons (n = 3) as well as for the 1s2 and 2s2 pairs are computed for the Zn2+ closed-shell ion by means of the variational-perturbation method starting with the sum of one-electron Hartree-Fock operators as the zeroth-order Hamiltonian. The results allow an understanding of the electron correlation for pairs of electrons of the p and d type. For 3p3d pairs it has been found that the correlation energy for the singlet pair of 1D symmetry is lower than for the triplet pair 3D. The 3l-3l′ correlation energies are compared with the MBPT results of Kelly and Ron for Fe. The total correlation energy of the outer shell is -1.032 a. u.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560160110
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  • 131
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    Role of electron correlation in the quantum-mechanical calculations of the coulomb interaction energy in the DNA base pairs (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 71-77 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intermolecular electronic correlation contributions to the Coulomb component of the nucleic acid base interaction energy are estimated. The Coulomb energy is evaluated with the use of atomic monopoles, which are determined from the π-electronic densities calculated by the SCF method and by employing partially or completely optimized APSG wave functions. When the correlation is thus taken into account, a systematic decrease in atomic charges occurs; this effect is considerable only if an optimized orbital set is used. As a result, the Coulomb interaction energy due to the π-electronic atoms decreases from -1.13 to -0.85 kcal/mol for the AT pair and from -7.15 to -4.61 kcal/mol for the GC pair.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160111
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    Multimolecular clusters: Their isomerism and effective characteristics evaluated by quantum chemistryPart V in the series Multimolecular Clusters and Their Isomerism; Part IV, Ref. 25. (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 79-86 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for processing the enthalpy, entropy, and Gibbs free energy terms of formation of the individual isomers of n-particle clusters obtained by means of quantum-chemical calculations, to enable a comparison of these partial theoretical characteristics with the overall experimental ones. The general scheme of weighting treatment is illustrated by examples based on recent quantum-chemical results of studies of isomeric forms of (NO)2, (H2O)5 and (D2O)5, and CH3OH · 3H2O and CH3OH · 6H2O clusters.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560160112
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  • 133
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    Electronic factors affecting receptor binding of dibenzo-p-dioxins and dibenzofurans (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 87-110 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic structure of a series of 25 chlorinated dibenzo-p-dioxins and dibenzofurans has been characterized by means of the ab initio molecular fragment technique. This information has been employed to investigate some of the factors affecting the affinity of the molecules for the hepatic cytosol binding species described by Poland, Glover, and Kende. A quantitative structure-activity relationship involving electronic and steric parameters could be established from the data. It appears that the toxins act as electron acceptors in a charge-transfer complex with the receptor.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160113
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  • 134
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    Circular dichroism of large molecules (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 111-117 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of molecules, which are large compared to the wavelength of light, is considered. Explicit expressions are obtained for the circular dichroism and absorption of an exciton dimer and of a free particle on a helix. The dimensions are described for which the dipole approximation for the optical properties fails.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160114
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  • 135
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    Mechanisms of electron transfer through proteins (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 133-152 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of modern physical mechanisms of electron transfer in proteins is given. The tunnel electron transfer and donor-acceptor electron transfer through conducting states of a protein chain are discussed in detail. The expressions for the values of the electron resonance interaction and the formulas for probabilities of electron transfer between vibronic levels of donor and acceptor states in the presence of “transverse” and “longitudinal” relaxation are given.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160116
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  • 136
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    Some aspects of the DNA hypochromic effect theory (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 119-132 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The expressions for the polymer absorption band hypochromism and oscillator strength are studied in frames of the first-order perturbation theory. The physically justified approximations for a polymer hypochromism calculation are indicated. The uniform interpretation of the effect origin is given independently on the approximation used. In frames of the perturbation theory the DNA hypochromism formula is obtained, from which the known experimental dependences of hypochromism on chain length and polymer helicity degree follows directly. The analytic expression of the DNA hypochromism dependence on AT pairs content is obtained. It is established that in most cases for natural DNA the nucleotide sequence does not influence in practice the value of the hypochromic effect.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160115
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  • 137
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    Conformational analysis of double-helical polynucleotides (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 153-157 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intramolecular interaction energy of the regular double-helical polynucleotide as a function of variables that determine the mutual position of base pairs and sugar pucker was calculated using atom-atom potentials. The calculations showed the existence of two valley-like regions with minimal values on the energetic surface. One of them corresponds to the A family of nucleic acids, the other to the B family. The points that correspond to the models constructed by means of x-ray data are placed in a conformational space near the lines that describe the position of the bottom of the valleys.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/qua.560160117
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  • 138
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160201
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  • 139
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    Influence of solvent structure on the conformation of the native DNA molecule (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 847-855 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The investigation of the factors determining the formation and stability of the higher biopolymers structures is one of the most important trends of the development of molecular biophysics. A feature common to most macromolecular systems under physiological conditions is that they function in an aqueous environment. Thus, it is natural to assume that the peculiarities of biological macromolecules structures and their functional activity as well are closely related to the specific properties of such a unique solvent as water. The investigations of the conformational changes of biopolymer, induced by dehydration of the macromolecule, give information about the nature of the forces stabilizing its structure. The dehydration of the macromolecule in solution can be attained by addition of a nonaqueous cosolvent. Generally low-molecular-weight aliphatic alcohols, amides, and amines are used as a nonaqueous component. At present a vast number of experimental and theoretical data concerning the properties of water and aqueous systems are available. The specificity of water as a solvent arises primarily from the spatial hydrogen-bonded structure. The addition of a nonaqueous component exerts changes in this structure, which evolve to the singularities of the physical characteristics of water-nonelectrolyte mixtures. It is generally assumed that nonelectrolytes may be divided, according to their effect on the spatial water structure, largely into two basic classes: (1) the structure makers, i.e., the compounds of aliphatic alcohols type; (2) the structure breakers, i.e., the compounds of urea type. The agents belonging to the first class show a stabilizing effect in the range of low nonelectrolyte content. At a certain critical concentration, Ccrit, characteristic of each substance, the nonaqueous solute molecules leave the cavities of the spatial water structure which leads to a disruption of the latter. The agents belonging to the second class exert a structure-breaking effect even in the range of extremely low concentrations, which arises from their high competitive ability for hydrogen bonding.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160417
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  • 140
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    Mechanisms of charge separation in bacterial photosynthesis (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 877-882 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The physical aspects of the primary charge separation processes in bacterial photosynthesis are discussed. The donor-acceptor model of electron transfer due to participation of protein current states is used. The kinetics of photosynthetic reaction center (PRC) processes is investigated and the PRC energetic scheme is constructed using the nonequilibrium density matrix method. It is shown that with allowance for the effect of vibrational sublevels of states participating in transitions the theory describes well experimental data.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160421
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  • 141
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    Orbit-orbit interaction in the NO-Fe(II)Hemoproteins studied by the low-temperature magnetic circular dichroism: Dynamic Jahn-Teller effect detected by MCD (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 883-889 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper analyzes the low-temperature magnetic circular dichroism of NO-Fe(II)hemoproteins in detail. We include the Jahn-Teller effect in our consideration of the low-temperature MCD results.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160422
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  • 142
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    Quantum-chemical investigation of spatial and electronic structure of verdazyl and its derivatives (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 891-895 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The unrestricted HF method in the INDO approximation with optimized geometry was used to describe the electronic structure of the hetero-ring of verdazyl and the derivatives of the latter. The results obtained are in good agreement with the experimental EPR spectra of triphenylverdazyl radical and its dipole moment. These data may be a basis for understanding and predicting the chemical properties and reactivity of verdazyl and its derivatives.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/qua.560160423
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  • 143
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160501
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  • 144
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    Nucleotide. IXTeil 8: [1].. Synthese und Eigenschaften von 1-(2′-Desoxy-D-ribofuranosyl)-lumazin-3′-monophosphaten (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1171-1178 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleotides. IX. Synthesis and properties of 1-(2′-deoxy-D-ribofuranosyl)-lumazin-3′-monophosphatesThe synthesis of various 1-(2′-deoxy-α-[and β-]D-ribofuranosyl)-lumazine-3′-monophosphates 25--30 starting from the corresponding pteridine nucleosides 1--6 is described. Monomethoxytritylation in 5′-position to 7--12, phosphorylation by cyanoethylphosphate to 13--18, and deprotection by acid and base treatment afforded the lumazine nucleotides 25--30 in good overall yield. The various reaction products have been characterized by physical means, such as UV. spectra, pK-values and their chromatographical and electrophoretical behaviour. Enzymatic dephosphorylations by alkaline phosphatase led to the starting material 1--6 with a 3--4 times slower hydrolysis rate in comparison to Tp.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19790620426
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  • 145
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    Intramolekulare Inversionssubstitution am Dreiring von 77exo-Brombicyclo[4.1.0]heptan-3endo-ol unter Bildung eines TetrahydrofuranringesAus der Dissertation von H.N., Universität Giessen 1977, und der Dissertation (Nr.6277) von R.D., ETH Zürich 1978. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1162-1170 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intramolecular Substitution under Inversion at the Threemembered Ring of 7exo-Bromobicyclo[4.1.0]heptan-3endo-ol yielding a Tetrahydrofuran RingThe reaction 1a → 2a involving substitution at a cyclopropane carbon atom can be observed only with the bromophilic alkyllithium reagents but not with the bases lithium diisopropyl amide (LDA) (Table 1) or potassium t-butoxide (KTB). The mechanism must be an insertion as outlined in Scheme 1. - The monobromides 1b, 1c and 1d are prepared stereoselectively from the acetal 3a. Again, cyclization of 1b takes only place with LDA in the presence of alkyllithium (Table 2, entries 1--4) suggesting an insertion mechanism (route (a) or (b) in Scheme 2). In contrast, KTB effects the substitution in high yield with no loss (from 1c) or incorporation of deuterium at the cyclopropane substitution center (Table 2, entries 5--7); the possibility is discussed that this process is an SN2-type reaction.
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  • 146
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    Nucleotide. X.Teil 9: [1]. Synthese und Eigenschaften von Dinucleosidmonophosphaten mit 2′-Desoxyadenosin und 1-(2′-Desoxy-β-D-ribofuranosyl)-lumazinen als Bausteine (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1179-1193 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleotides. X. Synthesis and properties of dinucleoside monophosphates with 2′-deoxyadenosine and 1-(2′-deoxy-β-D-ribofuranosyl)-lumazines as building blocksThe synthesis of various dinucleoside monophosphates 16--20 consisting of 2′-deoxyadenosine and 1-(2′-deoxy-β-D-ribofuranosyl)-lumazines via the triester approach is described. The fully protected phosphotriesters 6--10 as well as the partially deblocked intermediates 11--15 have also been isolated and characterized by physical means. Intramolecular interactions in 16--20 have been investigated by the determination of the hypochromicities and CD. spectra revealing a more or less distinct stacking effect in dependence of the 6,7-substituents in the lumazine moiety as well as the polarity of the internucleotidic linkage. Enzymatic degradations of the dinucleoside monophosphates with snake venom and spleen phosphodiesterase are depending strongly on various structural features indicating a much lower substrate specificity especially in presence of 6,7-diphenyl-lumazine as an aglycone with the latter enzyme.
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    URL: http://dx.doi.org/10.1002/hlca.19790620427
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    Photoenolisation. X.Parts VIII and IX, see [2 l, m].. An ab initio SCF-CI study (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 699-710 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The processes involved in photoenolisations are theoretically simulated by an ab initio SCF-CI method, using cis-2-butenal as a prototype structure. The prominent role of the hydroxyl group conformation in the resulting transient (2a) is emphasized; its rotation ‘out of the reaction site’ allows the next reaction paths to proceed exothermally. The equilibration of the different types of twisted biradicals in the triplet manifold, which only involves a low energy barrier, is thus possible, populating in quite equal weights the precursors of both E- and Z-dienols. In the singlet state, the formation of the Z-isomer is expected to be kinetically dominant. An examination of the role of the substituents suggests that, in related systems, the steric crowding induces important structural relaxation of the dienol geometries.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19790620309
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  • 148
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620801
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  • 149
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    Erratum (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2516-2516 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620746
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  • 150
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    High Pressure 17O-FT-NMR. Evidence for the Associative Nature of Substitution Reactions on Mn2+ in WaterHigh pressure NMR. kinetics, part 9. For part 8 see [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2511-2516 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The water exchange on [Mn(H2O)6](ClO4)2 in aqueous solution has been studied as a function of pressure (up to 250 MPa), measuring 17O-FT-NMR. linewidths of the free water resonance at 8.13 MHz. A pressure independent volume of activation, ΔV≠ = -6.2 ± 0.2 cm3 mol-1 is obtained, producing a clear evidence that, contrary to general belief, the mechanism for solvent exchange on Mn2+ is an associative interchange (Ia).
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19790620745
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  • 151
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    Mitteilungen (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2517-2518 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620747
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  • 152
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    The Radical Anions of Some Substituted [2.2]Paracyclophanes (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2569-2576 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical anions of the following substituted [2.2]paracyclophanes have been characterized by ESR. and ENDOR. spectroscopy: 4, 16-dicyano- (o-2), 4, 12-dicyano- (p-2), 4,5,12,13-tetracyano- (3) and 4,5,12,13-tetrakis (alkoxycarbonyl)- [2.2]paracyclophanes (4-R, where R = Me, Et, iPr or tBu is the ester alkyl group); 4,5-bis(methoxycarbonyl)[2.2]paracyclophane-12, 13-dicarboxylic anhydride (5); [2.2]paracyclophane-4,5:12, 13-tetracarboxylic bisanhydride (6) and bisimides (7-R, where R = H, D, Me or Ph is the substituent at the imide N-atom). Comparison of the hyperfine data for these radical anions with those for analogously substituted derivatives of benzene indicates that the most prominent coupling constants are approximately halved on passing from the latter to the former. Lowering of the symmetry, as a consequence of ion pairing, has been observed for the radical anions 4-iPr\documentclass{article}\pagestyle{empty}\begin{document}$^{\ominus \atop \dot{}}$\end{document} and 4-tBu\documentclass{article}\pagestyle{empty}\begin{document}$^{\ominus \atop \dot{}}$\end{document} associated with the counterion K⊕ in 1,2-dimethoxyethane at 183 K, but not for 4-Me\documentclass{article}\pagestyle{empty}\begin{document}$^{\ominus \atop \dot{}}$\end{document} and 4-Et\documentclass{article}\pagestyle{empty}\begin{document}$^{\ominus \atop \dot{}}$\end{document} under the same conditions. This result suggests that the migration of K⊕ between the preferred sited in two equivalent ion pairs is slowed down by the steric hindrance arising from the bulky iPr and tBu ester groups.
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  • 153
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    Die Cope-Umlagerung als Prinzip einer repetierbaren Ringerweiterung (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2630-2654 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Cope Rearrangement, a Reaction for Repeatable Ring ExpansionsStarting with the unsaturated β-ketoesters of type I, a vinyl group is introduced into the β-position by 1,4-addition of vinyl magnesium chloride to give II (Scheme 3). Treatment of the β-ketoester II with phenyl vinyl sulfoxide in the presence of sodium hydride yields the sulfoxides III, which on thermolysis lead to the α, β-divinyl ketoesters of type IV via elimination of sulfinic acid (Scheme 3). The Cope-System IV undergoes rearrangement to V, which is again an unsaturated β-ketoester. The latter is suitable for a further ring expansion sequence. These reaction steps were carried out with the nine-, twelve- and fifteen-membered ketoesters 32, 33 and 34, as well as with the open-chain compound 35 (Table 1). With the cyclohexane derivative 31, ring expansion could not be achieved with the described sequence.
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  • 154
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    A New α,β-Enone → Alkynone Fragmentation. Syntheses of exaltone® and (±)-muscone (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2655-2660 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: p-Toluenesulfonylhydrazones of α, β-unsaturated ketones undergo an alkynone fragmentation in high yield when treated with electrophiles under basic conditions. With N-bromosuccinimide in alcohols, the p-tosylhydrazones 4a and 4b yielded in a one-pot reaction the cyclic 4-alkyn-1-ones 5a and 5b; these were converted to Exaltone® (1a) and muscone (1b) on catalytic hydrogenation.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19790620815
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  • 155
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    31P-NMR. Measurements on Palladium-Phosphine Complexes. Nuclear overhauser effects and spin-lattice relaxation times (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 838-843 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 31P{1H} nuclear Overhauser effects (NOE's) and 31P-spin-lattice relaxation times (T1) for a series of trans-[PdCl2P2], P = PEt3, PPr3n, PBu3n, PMe2Ph, PMePh2, P(p-Tol)3, P(cyclohexyl)3 complexes are reported. Both the NOE and T1 values depend upon the choice of solvent. The dipole-dipole mechanism dominates the spin-lattice relaxation of the coordinated phosphorus atom with the T1 values for the PEt3, PPr3n, and P (cyclohexyl)3 complexes decreasing with increasing molecular weight of the phosphine.
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  • 156
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    Photooxygenation of 3,3-dialkylsubstituted allyl alcohols. Occurrence of syn preference in the ene addition of 1O2 at E/Z-isomeric allyl alcohols (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 816-829 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dye-sensitized photooxygenation (1O2-reaction) of the symmetrically 3,3-dialkyl-substituted allyl alcohols 1-6 (A, Table 1) and the E- and Z-isomers of the 3-methyl-3-alkylsubstituted allyl alcohols 7-11 (A1, Table 2) has been studied. The α, β-epoxyaldehydes B and B1 and the β-hydroperoxy-homoallyl alcohols C, C1 and D1 were practically the sole oxygenation products formed. The rate and selectivity of the 1O2 additions were found to be markedly dependent on the degree of substitution (i.e. H-availability) at the allyl position which is Z-orientated to the carbinol group. The allyl alcohols with a Z-3-methyl group, 1 and the E-isomers of 7 to 10, showed practically the same reactivity towards 1O2 and formed only the two oxygenation products of type B1 and C1 (ratio close to 60:40). In contrast, the allyl alcohols with a Z-3-methylene group, 2 and the Z-isomers of 7 to 9, reacted more slowly with 1O2 and yielded all the three possible products B1, C1 and D1 in a very different ratio of ∼ 80:10:10. However, from both the E- and Z-isomers of the alcohols 7 to 10 the formations of the two oxygenation products were always strongly favoured (85-100%) which result from 1O2 additions at the disubstituted side of the double bond. This behaviour is thus completely analogous to that of the corresponding trisubstituted olefins previously studied [1]The same side-specific selectivity in 1O2 ene additions to several E/Z-isomeric and deuterium-labelled olefins has also been described recently by C.M. Stephenson et al. [2] (we thank Dr. V. Rautenstrauch and Prof. C.W. Jefford for informing us about this work). The similar behaviour of enol ethers, which react with 1O2 preferentially at the RO-substituted side, had been observed earlier by C.S. Foote et al. [3] and extended to numerous derivatives by J.M. Conia et al. [4] [5]. and follows a new selection rule, termed syn-preference [1], in the ene addition of 1O2.
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  • 157
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    Syntheses of (+)-(S,S)-(cis-6-Methyltetrahydropyran-2-yl)acetic acid and of (-)-(R,R)-Didesoxy-pyrenophorine Using a New d5-ReagentThe work described here was done in 1977, see PhD-Thesis of M.P., Justus-Liebig-Universität, Giessen, Oct. 1978.The acceptor (a)/donor (d) nomenclature of synthetic methodology and a classification of the methods of reactivity umpolung are described in a review article [3]. According to this nomenclature, an enolate, an enone, and a dienone are d2-, a3-, and a5-reagents, respectively.. Preliminary communication (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 843-846 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Li/K-derivative 6 is used to synthesize the title compounds (3a and 4a) in enantiomerically pure form from (-)-(S)-propylene epoxide. The C,C bond forming key step leading to the hydroxyketone 7 is followed by cyclization (→, 8), Beckmann cleavage (→ 9b) and hydrolysis to 3a (recently isolated from civet). Base treatment of 3a opens the ring (10) to give the hydroxyacid 1 which is cyclized to the macrolide 4a. The synthetic usefulness of the highly nucleophilic doubly reduced dienone system 6 as d5-reagent (see synthons 2) is thus demonstirated.
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    URL: http://dx.doi.org/10.1002/hlca.19790620322
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  • 158
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    Stereoselektive Synthese von Cyclopropylkohlenhydraten (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 866-871 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereoselective synthesis of cyclopropylsugarsUse of the phase-transfer catalysis significantly increased the yield of the reactions leading to the known compounds 2 and 3. Stereoselective cyclopropylation of 3 and 4 and 8, was brought about using in the first instance the Simmons-Smith's reagent, whereas the reaction of dichlorocarbene led to 6 easily dechlorinated to 8. Both diastereoisomeric cyclopropylsugars 4 and 8 were transformed into the corresponding ethyl glycosides.
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  • 159
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    Propellanes. L. Further support for control by secondary orbital overlap during Diels-Alder reactions of certain propellanesPart XLIX: see P. Ashkenazi, M. Peled, E. Vogel & D. Ginsburg, Tetrahedron, in press.,Dedicated to Prof. Dr. h.c. A.S. Dreiding on the occasion of his 60th birthday (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1326-1329 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast to the behavior of 4-substituted-1,2, 4-triazoline-3, 5-diones which add to the syn-face of the cyclohexadiene with respect to the hetero-ring in propellanes of type 1, dienophiles containing a C, C double bond instead of an N, N double bond add exclusively to the anti-face of the same substrates. This supports our thesis that these reactions are controlled by secondary orbital interaction between the N, N dienophiles and the hetero-ring of the substrates, an interaction which cannot exist in the C, C dienophiles.
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    URL: http://dx.doi.org/10.1002/hlca.19790620446
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  • 160
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    Minor and Trace Sterols in Marine Invertebrates. XIIFor paper XI in this series, cf. [1].. Occurrence of 24 (R + S)-isopropenylcholesterol, 24 (R + S)-methylcholesta-5, 25-dien-3β-ol, and 24 (R + S)-methylcholesta-7, 25-dien-3β-ol in the caribbean sponge, Verongia cauliformisInshore Marine Shallow Water Ecosystem Project Contribution No. 47. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1310-1318 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In addition to the two new sterols verongulasterol 11 and 25-dehydroaplysterol 13 of Verongia cauliformis3), which were reported earlier [2] [3], the minor and trace sterols of this sponge include five new sterols listed in the title (with the exception of the known 24 S-methyl-cholesta-5, 25-dien-3β-ol (codisterol, 1b). The isolation of the 24(R)-epimer of codisterol is of interest, as this compound is a possibly biosynthetic precursor for aplysterol 12, 25-dehydroaplysterol 13, and verongulasterol 11 (all 24R) which occur in the same sponge [2]. A partial synthesis from fucosterol (4) of 24 (R + S)-isopropenylcholesterol (9), and of 24-isopropylcholesterol (10) is described.
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  • 161
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    Zur Biogenese der Betacyane: Versuche mit [2-14C]-DopaxanthinHerrn Professor Dr. André S. Dreiding zu seinem 60. Geburtstag gewidmet (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1330-1339 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the biogenesis of betacyanins. Expaiments with [2-14C]-dopaxanthineLabelled dopaxanthine is prepared from betanin by a double exchange procedure replacing first its cyclodopa part by diethylamine and effecting the second exchange with 2-[14C]-dopa on the purified intermediate ‘DEA-betalain’; the specific activity delivered with the dopa allowed accurate determination of ∊ in the electronic spectrum of dopaxanthine (λmax 488 nm, ∊ = 41.800). The C(2)-labelled dopaxanthine is incubated into the fruits of Opuntia bergeriana. The incorporation rates into betanin are found to correspond approximately to those obtained in earlier experiments with labelled dopa alone: Only 1--5% of the label showed up in the cyclodopa moiety of the betanin (which is isolated as cyclodopa-glucoside) whereas 99--95% of the radioactivity was associated with the betalamic acid part (recovered in form of indicaxanthine).
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  • 162
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    Etude par résonance paramagnétique électronique des radicaux piégés dans un monocristal de diméthylarsinate de sodium irradié aux rayons X (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1605-1613 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: E.S.R. study of radiation damage in a single crystal of sodium dimethyl arsonateL'irradiation aux rayons X, à 77 K, d'un monocristal de diméthylarsinate de sodium provoque le piégeage de \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \left({\rm O} \right){\rm As}\left({{\rm O}^ -} \right)\mathop {\rm C}\limits^ \cdot {\rm H}_{\rm 2} $\end{document} et de (CH3)2AsO2--. En fonction de la température ces radicaux se réorientent ou donnent naissance à de nouvelles espèces radicalaires. Les tenseurs g et de couplage hyperfin avec 75As ont été déterminés à 105 K, 165 K, 215 K et 295 K et permettent de proposer une identification de plusieurs espèces radicalaires localisées sur l'atome d'arsenic. Le rǒle de la température d'irradiation et l'influence de l'oxygène sur la réactivité des radicaux piégés dans le cristal sont également étudiés.
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  • 163
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    Réactions de Friedel et Crafts de dérivés aromatiques sur les composés dioxo-1,4,2,3-non saturés. IV. Réactions des hydroxy-5-ouchloro-5-diméthyl-3,5- ou diméthyl-4,5-dihydro-2,5-furannones-2Communications I, II et III voir [19] [4] et [3]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1614-1621 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Friedel-Crafts reactions of aromatic derivatives with 1,4-dicarbonyls 2,3-éthylenic compounds. Part IV. Reactions of 5-hydroxy or 5-chloro 3,5-dimethyl or 4,5-dimethyl 2 (5 H) furanonesWe studied the Friedel-Crafts reactions of 2-(5H)-furanones. In the presence of sulfuric acid and of an aromatic derivative, 5-hydroxy- or 5-chloro-5-methyl-2-(5H)-furanones with one methyl group either in the 3 position, or in the 4 position generally give the corresponding 5-aryl-2-(5H)-furanones, while with aluminium chloride, it is possible to obtain, when a reaction takes place, isomeric 1H-indenecarboxylic acids. However, in a particular case, an addition to the substrate's double bond is observed. The 3-aryl-5-hydroxy-tetrahydrofuran-2-one obtained is methylated in two ways and gives either a cyclic product, or a linear one. In two cases tautomerism between 1H-1-indenecarboxylic acid and 1H-3-indenecarboxylic has been shown by 1H-NMR.
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  • 164
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    Dérivés d'énose- et d'ynosephosphonates et composés voisinsSucres phosphorés III; II: [1].. Communication préliminaireUne communication plus détaillée paraîtra ultérieurement. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1622-1625 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of enose- and ynosephosphonates and related compounds. Preliminary communicationThe gem-dibromo terminal enoses 1 and 7 are convenient sources of glycosylacetylenes which upon reaction with phosphorus electrophiles gave the phosphorusbearing acetylenic sugars 4, 5 and 8. Compounds 5 and 8 underwent cycloaddition reactions leading to isoxazolyl-C-glycosides 6 and 9 respectively. The nitroolefinic sugar derivative 11 gave upon bromination-dehydrobromination the first example of a new kind of potentially useful synthetic intermediates, the gem-bromonitroenose 12. The enosephosphonate 13 was also prepared from 11. The diglycosylhydroxylamine 18 represents another type of phosphorus-bearing acetylenic sugar derivative. Some 1H- and 13C-NMR. data relative to the new types of phosphorus-containing sugar derivatives synthesized are given.
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620401
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  • 166
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    Notiz über einen Zugang zu β, γ-ungesättigten Carbonsäurederivaten mit Hilfe der Amidacetal-Claisenumlagerung. Über synthetische methoden, 17. Mitteilung16. Mitteilung, siehe [1].André Dreiding zum 60. Geburtstag gewidmet (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1922-1931 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Note on a preparation of β, γ-unsaturated carboxylic acid derivatives using the amide acetal Claisen rearrangement3-(Trimethylsilyl)allyl alcohols smoothly undergo the amide acetal Claisen rearrangement furnishing allyl silanes. Subsequent protolysis with HF at -20° provides a convenient, stereoselective method for the preparation of β, γ-unsaturated carboxylic acid derivatives. Three model examples illustrate the procedure.
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    Isomerisierung der Bis(triphenylphosphin)platin(0)-Komplexe von Bicyclo[4.2.1]non-1-en und Bicyclo[4.2.1]non-1(8)-enAuszugsweise vorgetragen auf der GDCH-Hauptversammlung, München, 15.September 1977 und auf der Herbstversammlung der Schweizerischen Chemischen Gesellschaft, Bern, 20.Oktobre 1978.Herrn Prof. Dr. Edgardo Giovannini zum 70. Geburtstag gewidmet (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2181-2185 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isomerization of the Bis(triphenylphosphine)platin(0) Complexes of Bicyclo[4.2.1]non-1-ene and Bicyclo[4.2.1]non-1(8)-eneIsomrisation of the Bredt-Olefins 3 and 7 as the bis (triphenylphosphine)-Pt(0) complexes 1 and 8, respectively, has been observed. The bridgehead-olefin 3 as well as the bicyclic olefins 4, 5 and 6 have also been isomerized with catalytical amounts of (ethylene)bis(triphenylphosphine)platinum(0) (2).
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    URL: http://dx.doi.org/10.1002/hlca.19790620715
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  • 168
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    Anwendung der «Zip»-Reaktion zur Synthese eines 53gliedrigen Polyaminolactams. 8. Mitteilung über Umamidirungsreaktionen7. Mitt. s. [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2317-2324 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Use of the ‘Zip’ reaction for the synthesis of a 53-membered polyminolactamThe synthesis of N-(39-amino-4, 8, 12, 16, 20, 24, 28, 32, 36-nonaaza-nonatriacontyl)-12-dodecanlactam (1)In ‘5’ wurden die Verbindungen 1 als 1-(39-Amino-4,8,12,16,20,24,28,32,36-nonaazanonatriacontyl)-1-azacyclotridecan-2-on, 4 als 7-Chlor-1-phthalimido-4-tosyl-4-azaheptan, 5 als 7-Jod-1-phthalimido-4-tosyl-4-azaheptan und 20 als 1,5,9,13,17,21,25,29,33,37,41-Undecaazatripentacontan-42-on bezeichnet. has been described. The formation of synthon 2 , used for the chain extension of the known 12[6] shown in Scheme 2 , is demonstrated in Scheme 1 . In presence of base (KAPA-reagent), 1 undergoes the so called ‘Zip’-reaction resulting in a ring-expansion by 40 members which leads to 20 .
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  • 169
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    The Reaction of Cyclopropyl Ketones with Acetyl Methanesulfonate. An efficient ring opening under neutral conditions with regiospecific enol acetate formation and stereo-controlled nucleophilic addition. Preliminary communicationPresented at the ESOC I Conference, Köln (1979). (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2338-2340 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclopropyl ketones are readily cleaved under neutral conditions at room temperature by the combined action of acetyl methanesulfonate and nucleophiles such as Br-, I-, and MsO-. The high-yield reaction involves regiospecific enol acetate formation with a stereoselectivity of nucleophile addition which is compatible with an SN2-type opening of the cyclopropyl ring.
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    URL: http://dx.doi.org/10.1002/hlca.19790620730
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  • 170
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    The Effects of Homoconjugated Cyclopropane and Oxirane Rings on the Diels-Alder Reactivity of 2,3-bis (methylidene)norbornane‘Interaction between non-conjugated chromophores’, part 9; part 8 [1], part 7 [2], part 6 [3], part 5 [4], part 4 [5], part 3 [6], part 2 [7], part 1 [8].This work has been presented to the fall meeting of the ‘Société suisse de chimie’, Bern, oct. 1978.Dedicated to Professor Dr. Edgardo Giovannini on his 70th anniversary (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2341-2349 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of 6exo, 7exo-bis (methylidene)-tricyclo[3.2.1.02,4]octane (6) is described. The reactivity of 6 towards tetracyanoethylene is evaluated and compared with that of exo-2,3-epoxy-5,6-bis (methylidene)norbornane (5), 2,3-bis-(methylidene)norbornane (1) and other related dienes. The cyclopropane group in 6 exerts an unsignificant rate retardation effect on the Diels-Alder reactivity of this diene relative to that of 1, whereas a relatively important rate retardation effect is caused by the exo-oxirane ring in 5. The observed effects are probably due to electronic factors (through-space and through-bond interactions).
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  • 171
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    Strukturen von 13 Diterpenen (Coleonen) aus Blattdrüsen von Solenostemon sylvaticus und Coleus garckeanus (Labiatae) (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2374-2383 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Leaf-gland pigments from labiatae: structures of 13 diterpenoids (coleons) from Solenostemon sylvaticus (GÜRKE) T.T. AYE and Coleus garckeanus VATKEThe above mentioned East-African labiatae have been investigated for their leaf-gland pigments. The two plants contain very similar abietanoic diterpenoids. Besides the already known coleons O (5a) and W (1a), 11 novel compounds have been isolated and their structures established:Diosphenol: 16(or 17)-O-acetyl-coleon W (1b).Diketones: Coleon X (16 or 17)-acetoxy-11, 12, 14, 17 (or 16)-tetrahydroxy-abieta-8, 11, 13-triene-6,7-dione (2a); 16 (or 17)-O-acetyl-coleon X (2b).Spiro-coleons: 6-O-acetyl-19-acetyloxy-coleon Q (3b); 12-O-desacetyl-7-O-acetyl-19-acetyloxy-coleon Q (3c); 12-O-desacetyl-7-O-acetyl-19-acetyloxy-coleon P (3e); 12-O-desacetyl-7-O-acetyl-3β, 19-diacetyloxy-coleon Q (4b); 19-acetyloxy-coleon O (5b); 12-O-desacetyl-6-O-acetyl-17-acetyloxy-coleon P (7); 7-desoxy-12-O-desacetyl-3-acetyloxy-coleon N (6b); coleon Z (8).Compound 7 contains a spiro cycloprope unit, substituted by one carbonyl and two carbinol functions. Compound 8 (Coleon Z) contains a unique cis-butadiene unit formed from C(3)-C(4)-C(18)-C(19).
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  • 172
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    Carbocyclische Verbindungen aus Monosacchariden. III. Mitt. s.[1].. Umsetzungen in der Mannosereihe (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2400-2410 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbocyclic compounds from monosaccharides. II. Transformations in the mannose seriesUpon treatment with Zn in refluxing aqeous ethanol or butanol, the anomeric mannopyranosides 11 and 14 yielded the aldehyde 15 which was subjected (via its N-methyl-nitrone) to an intramolecular nitrone-olefine cycloaddition leading diastereoselectively to 18 in a yield of 64% from 14. Minor products of this reaction sequence were the compounds 19, 20 and 21. Similarily, the easily accessible unsaturated furanose 26, upon treatment with N-methyl-hydroxylamine gave the isoxazolidines 27 (84%) and 28 (3%), thus showing that a free 4-hydroxy group is not detrimental to this intramolecular nitrone-olefin cycloaddition. The configuration of 18, 27 and 28 (resp. 29) were determined by spectroscopic means; that of 27 was further proven by transformation into the compound 31, of which an X-ray analysis was performed.
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  • 173
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    Carbocyclen aus Monosacchariden. III.II. Mitt. vorstehend. Zur Diastereoselektivität der Bildung von Cyclopentanderivaten. Umsetzungen in der Galactosereihe (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2411-2431 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbocycles from monosaccharides. III. Concerning the diastereoselective formation of cyclopentane derivatives. Transformations in the galactose series.The diastereoselectivity of the intramolecular nitrone-olefine cycloaddition of 1, 3 and 4 (Scheme 1), yielding only 2, 5 and 6 but none of the isomers 8, 9 and 10 is explained by assuming a kinetic control and postulating that the relative activation energies of the two relevant transition states in the cyclization of e.g. 1 can be estimated from the conformers A and B, the latter being destabilized by a synperiplanar arrangement of the nitrone function and the 2-alkoxy-group (Scheme 2). It is further postulated, that this destabilization is responsible for the formation of (2,3)-trans configurated products. Since 2, 5 and 6 are presumably thermodynamically more stable than 8, 9 and 10, a case was investigated, where the cycloaddition can either give thermodynamically less stable (2,3)-trans-product such as 12 or a thermodynamically more stable (2,3)-cis-product such as 13. 12 and 13 could both be formed from the aldehyde 25 via the nitrone 11 (Schemes 3 and 5). Treatment of the galactoside 16 first with Zn in aqueous butanol (forming among other products 25 and its 2-debenzyl-oxy-derivative) and then with N-Methyldroxylamine yielded the isoxazolidines 12 (72%), 13 (2%) and 27 (7%) (Schemes 4 and 6). Similarily, the anomeric silylated galactosides 17 and 23 gave 29 (78% from 17, 77% from 23) and 27 (5% and 3%). Upon desilylation, 29 gave 32, which was converted into 12. The structure of the isoxazolidines was unambiguously deduced from their NMR. spectra and those of their derivatives 33 and 34. Compound 32 was further transformed into its deoxyderivative 36. The high diastereoselectivity of the cycloaddition restricts the number of diastereomeric, pentasubstituted cyclopentanes available by this method. However, cyclization of the 2-Hydroxy-aldehyde 37 (Scheme 8) gave the kinetically less favoured isomer 40 in a higher proportion, showing the differential influence of hydrogen-bonds on the relevant activation energies. Thermolysis of 32 gave 40 (79%) and 41 (11%). The structure of 41 was deduced from its NMR. spectra and those of its derivatives 42 and 43. Thermolysis of 29 gave, after desilylation, 41 (42%), 40 (22%) and 32 (13%) and thermolysis of 6 lead to a 25 : 75 equilibrium with 44 (combined yield 90%). These transformations illustrate means leading to additional isomers and are in agreement with the proposed explanation of the diastereoselectivity in question.
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  • 174
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    The Absolute Configuration of the Fungal Metabolite Verrucarin B. Biosynthetic Consequences. Verrucarins and roridins, 36th communication (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2699-2705 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute configuration of verrucarin B (2) has been determined by a single crystal X-ray diffraction analysis. This result permits the stereochemistry of the biogenetic transformation of mevalonic acid (12) to verrucarinic acid (7) to be deduced.
    Additional Material: 1 Tab.
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  • 175
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    Crocetin-dialdehyde from Coleus forskohlii BRIQ., LabiataeSyn. C. barbatus; chromatographicat comparison of an ether/acetone extract from authentic samples clearly showed that C. forskohlii differs either from C. barbatus (BENTH.) AGNEW (origin Kenya) yielding the deeply red p-quinomethanes Coleon E [1] and F [2] and from a Brazilian C. barbatus from which the colourless barbatusin was isolated as the main diterpenoid [3]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2706-2707 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus den Wurzeln der im Titel genannten Labiate wurde Crocetin-dialdehyd (8,8′-Diapo-carotin-8,8′-dial) (1), C20H24O2, isoliert. Chromatographisch wurde diese Verbindung auch in den oberirdischen Teilen dieser Pflanze nachgewiesen.
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  • 176
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    Iridoidglucoside aus Leucocarpus perfoliatus G. DON. 174. Mitteilung über organische Naturstoffe172. Mitt. s. [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2708-2711 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Iridoidglucosides from Leucocarpus perfoliatus G. DON.The known iridoid glucoside boschnalosid (1) was isolated from Leucocarpus perfoliatus in addition to the hitherto unknown yuheinosid, for which structure 2 was deduced.
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  • 177
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    Einfache Synthese von 6-[4-Methyl-3-cyclohexen-1-yl]-hept-5-en-2-on, einer Vorstufe für α-Bisabolen und dessen Isopropenyl-Isomers. Terpene und Terpen-Derivate, 10. Mitteilung9. Mitt. siehe [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2724-2731 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple Synthesis of 6-[4-Methyl-3-cyclohexen-1-yl]-5-hepten-2-on, a Precursor of α-Bisabolene and Its Isopropenyl IsomerThe alcohol 14 reacts with vinyl resp isopropenyl ether by Claisen rearrangement to give the aldehyde 16/17 resp. the ketone 3/4. Contrary to other reports this separable (E/Z)-mixture also occurs as a result of the synthesis following the pathway 7 → 8/9 → 10/11 → 12/13 (see also [2]). The bisabolene isomers 5 resp. 6 are obtained by reaction of 3 resp. 4 with methylidene triphenyl phosphorane. A mixture of 1 and 5. however, is formed from 3 via the alcohol 18 and its acetate 19. Likewise 4 reacts via 20 and 21 to give a (2/6)-mixture.
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  • 178
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    Beitrag zur absoluten Konfiguration der Spermin-Alkaloide O-Methylorantin und Aphelandrin. 175. Mitteilung über organische Naturstoffe173. Mitt. s. [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2712-2723 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contribution to the Absolute Configuration of the Spermine Alkaloids O-Methylorantine and AphelandrineThe absolute configuration of the spermine alkaloid O-methylorantine (1) isolated from Chaenorhinum minus (L.) WILLK. ET LGE. and Ch. villosum (L.) WILLK. ET LGE. was determined. Besides the difference in the substitution at C(31) (OCH3 versus OH) the constitution of 1 and aphelandrine (2) [6] is the same. This was established by spectroscopic evidence, by isomerization reactions of 2, orantine (4) and their derivatives (Scheme 2), and by degradation reactions of 1 and 4, respectively. The methyl ether 1 of orantine (4), the latter prepared by base catalyzed isomerization from aphelandrine (2), is in all respects identical with the natural O-methylorantine (1). Orantine (4) is identical (UV., CD., 1H-NMR. and TLC. evidence) with ephedradine A, recently isolated by Hikino et al. [8], who determined the absolute configuration of ephedradine A by X-ray analysis. The absolute configuration of aphelandrine (2) was related to the one of 4 by chemical degradation.
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  • 179
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    The Course of the Catalytic Hydrogenation/Isomerization Reaction of Steroidal Ring B Olefins in the 13β- and 13α-SeriesPart of the Ph.D. thesis ETHZ of G.A., in preparation.In memoriam Louis F. Fieser (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2732-2753 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The course of the catalytic hydrogenation and isomerization (H2/Raney-Ni/dioxane or H2/Pd/C/EtOH) of Δ5.7-, Δ7-, Δ8-, and Δ8(14)-steroid olefins was shown to depend strongly on the configuration at C(13). The known hydrogenation/isomerization of reactions of Δ5.7-dienes in the 13β-series to Δ7-(H2/Raney-Ni/dioxane) and Δ8(14)-olefins (H2/Pd/C/EtOH) were also confirmed in the 3β, 19-epoxy-13β- and 3-Oxo-19-acetoxy-13β-steroid series (e.g. 32 → 35 → 37, Scheme 3). On the other hand, in the corresponding 13α-steroid series the same reactions afforded the Δ7-. and the Δ8-olefins (mixture of products with H2/Raney-Ni/dioxane; quantitatively the Δ8-compounds with H2/Pd/C/EtOH; s. e.g. Scheme 3). A similar dependence on the C(13) configuration was observed in the allylic oxidation of these olefins with SeO2 (Fieser's test, see Table), and in the acid catalyzed opening of the 7α, 8α-epoxides (e.g. 60 → 62 + 63 in the 13β-series, and 56 → 64 + 65 in the 13α-series, Scheme 8).
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  • 180
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    Syntheses and Absolute Configuration of (E)- and (Z)-α-BisabolenesDedicated to Professor E. Giovannini on the occasion of his 70th birthday (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 369-377 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereospecific syntheses of (E)- and (Z)-α-bisabolenes have made revision of the configuration of natural (+)-α-bisabolene from Opoponax oil necessary. 13C-NMR. spectroscopy has been used for the differentiation of these isomers.
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  • 181
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    Einige bestrahlungsexperimente mit 2, 1-Benzisothiazolen61.Mitt. über Photoreaktionen; 60.Mitt. s. [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 391-397 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some Irradiation Experiments with 2, 1-Benzisothiazoles2, 1-Benzisothiazole (1) on irradiation with a mercury high-pressure lamp in benzene/diethylamine yields, after acetylation, 2-acetylamino-benzaldehyde (3; Scheme 1). Similarly, irradiation of 3-chloro-2, 1-benzisothiazole (2) in benzene/diethylamine leads to a mixture of 3-dimethylamino-2, 1-benzisothiazole (6a) and N, N-diethyl-thioanthranilamide (7a; Scheme 2). Benzisothiazole 6a, on irradiation, is not transformed into 7a. On the other hand, when 2 is irradiated in methanol a mixture of 3-methoxy-2, 1-benzisothiazole (4a) and methyl anthranilate (5a; Scheme 2) is obtained. In this case, 4a on irradiation in methanol or ethanol also yields 5a. No exchange of the methoxy group in 4a is observed when the irradiation is performed in ethanolic solution. Thus, 2, 1-benzisothiazoles 1, 2 and 4a react photochemically by N,S-bond cleavage and hydrogen-atom abstraction from the solvent (Scheme 3). 3-Chloro-2, 1-benzisothiazole (2) shows a second photoreaction, i.e. nucleophilic exchange of the chloro substituent by methanol or diethyl amine. The latter reaction can also be observed thermally, e.g. in boiling methanol in the presence of methoxide ions.
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  • 182
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    Struktur der Sesquiterpene von Petasites hybridus (L.) G. M. et SCH.: Neopetasol-Abkömmlinge4. Mitt. über Petasites-Inhaltstoffe. 3.Mitt.: [1], Kurzmitt.: [2].Teil der Dissertation von A. N. [3]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 627-634 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure of Sesquiterpenes of Petasites hybridus (L.) G. M. et SCH.: Derivatives of NeopetasolThe structure of 5 compounds of the sesquiterpene fraction of petasites hybridus has been determined by combination of spectroscopic methods, especially by analysis of the 360-MHz-1H-NMR. spectra. Most natural products are esters of a sesquiterpene alcohol, which is the 7 β-epimer of petasol. The alcohol is named neopetasol.
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    URL: http://dx.doi.org/10.1002/hlca.19790620229
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  • 183
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    Hydroxid-bewirkte Halogenwasserstoff-Abspaltungen aus vic-Dihalogeniden unter heterogenen Bedingungen: Reaktionssteuerung dank überraschender Solvens- und Metall-EinflüsseTeil VIII der Reihe «Base-bewirkte Eliminierungsreaktionen» vorangehende Mitteilung: s. [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 635-640 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydroxide-Promoted Dehydrohalogenation of vic-Dihalides under Heterogeneous Conditions: Control Over the Reaction Outcome Due to Surprising Solvent and Metal EffectsSelective elimination of either one or two molecules of hydrogen halide from vic-dihalides can be conveniently achieved by employing solid sodium or potassium hydroxide in the presence of solvents such as glycol dimethylether or tetraethyleneglycol dimethylether.
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  • 184
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    Structure of Globularidin: An Unusual Iridoid Glucoside from Globularia alypumL.Part 1 in the series, ‘Glycosides of Globulariaceae’. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 644-646 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel iridoid glucoside, named globularidin, lacking the typical double bond between C(3) and C(4), has been isolated from the whole plant of Globularia alypum by the combination of open column- and high-performance liquid chromatography. The structure of this compound was established by chemical transformation and spectral data.
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    Mitteilungen (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 647-648 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/hlca.19790620233
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  • 186
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    Thermische Umlagerung von 2-Oxa-bicyclo [3.3.1]-non-7-en-3-on; eine neuartige Lactonumlagerung. Vorläufige MitteilungGewidmet Herrn Professor E. Havinga anlässlich seines siebzigsten GeburtstagesEine ausführliche Mitteilung soll in dieser Zeitschrift erscheinen. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 641-643 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal Rearrangement of 2-Oxa-bicyclo [3.3.1]-non-7-en-3-ones; a Novel Lactone RearrangementLactone (+)-2 was prepared by iodolactonisation and subsequent elimination in 51% yield from the known acid (+)-1 (Scheme 1). Alkylation of (+)-2 furnished (+)-3a, (+)-3b and (+)-3c, respectively (Scheme 2). Heating of (+)-3a in boiling DMF racemized the compound ((+)-3a ⇆ (-)-4a). Heating of (+)-3b and (+)-3c, respectively, equilibrated them with (-)-4b and (-)-4c, respectively. This results are interpreted as a [3.3]-sigmatropic rearrangement with a transition state as depicted in a.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620231
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  • 187
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620301
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  • 188
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    Atomic energy levels and oscillator strengths calculated with a screened potential (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 83-95 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A screened potential model (SPM) is formulated with Slater-type functions to reproduce the density of the electron shells. The orbital exponent for the valence shell is optimized to calibrate the SPM against experimental valence and Rydberg s and p energy levels for the alkali metals (Li, Na, and K) rare gases (He, Ne, Ar, and Kr), second-row atoms, and Cu, Zn, Mg, S, and Ga. The resulting one-electron wave functions are used to calculate the dipole and velocity forms of the oscillator strengths and 〈1/r3〉 for spin-orbit coupling. The excellent agreement with the averaged experimental results suggests that the SPM atomic orbitals are a good starting point for the evaluation of one-electron properties.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150109
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  • 189
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    Comparison of UHF and PHF methods for hyperfine structure calculations (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 97-107 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The validity of two models used in comparisons of the UHF and PHF methods in hyperfine structure calculations is investigated for the lowest 2P state of Li. An improved model for the angular splitting of the core orbitals is proposed and shown to give an accurate description of both the UHF and the PHF wave functions.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150110
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  • 190
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    14th Meeting of the international academy of quantum molecular science (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 131-131 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150113
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  • 191
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    Study of the quality of Gaussian basis sets for carbon and silicon: Calculations on methane and silane (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 261-270 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of Gaussian basis sets for carbon and silicon have been examined in terms of the one-electron properties of methane and silane. The convergence of the properties to their limiting values is not monotonic but, in general, a representation that involves five Gaussian functions per occupied atomic orbital on the heavy atom is sufficient to closely approach the limits. A relationship between the sizes and partitioned electronic energies is shown to hold to a good approximation for the Boys spatially localized molecular orbitals employed in this study.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150302
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  • 192
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    Surface structure and energy spectra of localized states (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 281-291 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple model for surface reconstruction is developed utilizing the next-nearest-neighbor approximation within the framework of molecular-orbital theory. Exact energy expressions for this model and various special cases are derived, and they are illustrated by numerical results. The influence of a very weak surface deformation on the energy spectrum of surface states is also discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150304
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  • 193
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    Modified bielectronic potential method for correlation energy (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 293-309 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Löwdin's correlation potential formalism has been used to define a modified bielectronic potential, allowing one to calculate the exact electronic energy, given the Hartree-Fock wave function. This modified potential is in principle peculiar to each electronic system, and is defined by a correlation factor depending on the interelectronic distance r2. The explicit calculation of the correlation factor has been performed for some two-electron atoms, in the 11S and 23S states, and for the beryllium atom. Examination of the results so obtained leads us to conclude in favor of the nonexistence of a universal modified bielectronic potential.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150305
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  • 194
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    Model quantum chemical studies of the electronic structure and aspects of reactivity of diol epoxides of aromatic hydrocarbons (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 271-280 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper offers a unified presentation of the main ring conformers of the diol expoxides, triol carbonium ions, and tetrols related to the “bay-region” benzo ring of carcinogenic metabolites of PAH and brings forward quantitative information through ab initio SCF computations about their relative energies. It substantiates and evaluates the energy of the syn epoxide-OH4 hydrogen bond and, on the contrary, refutes the significance of an O⃛H—O or an O-⃛H—O bond in the triol carbonium ions. It provides an explanation for the similar rates of acid-catalyzed hydrolysis of the syn and anti diol expoxides. It evaluates the stabilization of the triol carbonium ions due to the presence of a neighboring double bond and accounts for the spontaneous opening of protonated epoxides. Finally it accounts for cis hydrolysis of the syn diol epoxide and trans hydrolysis of the anit diol epoxide under acid conditions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150303
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  • 195
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    A dynamical theory describing superconductant DNA (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 333-341 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A dynamical model describing DNA as superconductant is proposed. The status of superconductivity is described as being represented by a radiation-induced harmonic oscillation of a parcel of π electrons between the reference level and critical temperatures. A set of field equations is used to describe the information exchange process mediated by a coherent wave phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150307
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  • 196
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    Theoretical studies of hemoproteins. I. Mathematical description of the allosteric effect (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 379-387 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new theoretical approach to the cooperativity of an enzyme has been proposed. When we applied the present theory to the allosteric effect of hemoglobin, we obtained a so-called Koshland-Nemethy-Filmer formula. Our theory suggested that the sigmoid curve becomes sharper when the affinity of the first oxygen molecule of the hemoglobin is smaller.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150404
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  • 197
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    Atomic dipole approximation and energies of interactions between purine and pyrimidine bases. I. Electrostatic interactions of adenine with uracil, thymine, thiouracils, dihydrouracil, and 5-fluorouracil (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 369-377 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The atomic dipole approximation has been employed to calculate the energies of electrostatic interaction between adenine and various pyrimidine derivatives. Minima of the interaction energy for various planar configurations were determined. Inclusion of the “monopole-dipole” and “dipole-dipole” terms in the multipole expansion improves considerably the agreement with experimental data. The effect of sulfur substitution has been investigated in detail. Formation of N—H…S hydrogen bonds is less favorable than of N—H…O bonds, due largely to the lower atomic dipole of the sulfur atom resulting from the shift of the π-electron charge toward the neighboring carbon. The results are relevant to the interactions of thiouracils in nucleic acids.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150403
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  • 198
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    Invariance properties of the multipole expansion with respect to the choice of the coordinate systemthis work was partially supported by the polish academy of sciences within the project mr.i.9. (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 701-711 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The physical interpretation of intermolecular interactions is usually based on the well-known multipole expansion of the inverse of the interparticle distance. The interaction energy is then interpreted as a sum of terms arising from the interaction of various multipole moments of both systems. It is supposed that the interaction energy calculated via the truncated multipole expansion generally depends on the choice of local coordinate systems through the coordinate dependence of the multipole moments. In this paper we prove that each term of the multipole expansion given in the form ∑k = 1 Ck/Rk is invariant with respect to identical translations and arbitrary rotations of the local coordinate systems. The invariant form of the convergence criterion of the multipole expansion is given and discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150613
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  • 199
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    Power moments of hydrogenic Green's functions and Green's functions of the second kind (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 717-729 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Power moments for all of the reduced hydrogenic Green's functions have been computed. These moments have the same form as the corresponding moments of the free-particle Green's functions. Green's functions of the second kind are defined, and uses for these objects in model potential theory and the theory of many-body Green's functions are pointed out. In the case of the ground state of the hydrogenic atom, the Green's function of the second kind has been given.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150615
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  • 200
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    Improved uncoupled Hartree-Fock (IUCHF) perturbation methods and bounds for the second-order energy in coupled Hartree-Fock perturbation theory (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 15 (1979), S. 745-750 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Different kinds of improved uncoupled Hartree-Fock methods are proposed for the calculation of second-order perturbation energies. Using these methods inequalities are derived for the error of the uncoupled procedure with geometric approximation.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560150617
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