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  • Chemistry  (35)
  • Computational Chemistry and Molecular Modeling  (3)
  • 1
    Electronic Resource
    Electronic Resource
    The vibrational spectra and structure of poly (rA-rU). Poly (rA-rU) (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 799-816 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Infrared and Raman spectra of aqueous poly(rA-rU)·poly(rA-rU), the double-helical complex containing strands of alternating riboadenylate and ribouridylate residues, display significant differences from one another and from corresponding spectra of poly(rA)·poly(rU), the double-helical complex of riboadenylate and ribouridylate homopolymers. Parallel studies on the copolymer and homopolymer complexes by cesium sulfate density gradient centrifugation, ultraviolet absorption spectroscopy, hydrogenion titration, 1-N oxidation of adenine residues by monoperphthalic acid and X-ray diffraction reveal, however, that the geometry of base pairing between adenine and uracil is closely similar in each complex and apparently of the Watson-Crick type. Therefore the differences observed between vibrational spectra of poly (rA-rU)·poly (rA-rU) and poly(rA)·poly(rU) are not due to different base-pairing schemes but may be attributed to differences in vibrational coupling between vertically stacked bases. Vibrational coupling may also account for the differences between infrared and Raman spectra of the same complex. Thus, the present results indicate that infrared and Raman frequencies of RNA in the region 1750-1550 cm-1 should be dependent on the base sequence.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120409
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  • 2
    Electronic Resource
    Electronic Resource
    Infrared spectra of transfer ribonucleic acids. III. Fragments of formyl-methionine tRNA from Escherichia Coli (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 681-698 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four fragments (named K, L, M, and N) of Escherichia coli formylmethionine transfer RNA have been prepared by a partial digestion with ribonuclease T1 followed by a chromatographic separation with a DEAE-Sphadex (A-25) column and then a DEAE-cellulose column. The fragment K is the anticodon fragment with 19 nucleotides (previously reported). L is a fragment with 57 nucleotides involving the 3′-terminal (CCA). M is a fragment with 51 nucleotides which is equal to L except that M lacks 6 nucleotides at the 3′-terminal. N is a fragment with 20 nucleotides which involved the 5′-terminal and corresponds to the complementary half to L. The infrared absorption spectrum has been observed of each of these fragments and two equimolar mixtures L + N and M + N in D2O solutions at several temperatures. The results indicate that at 37°C, K has about 4 hydrogen-bonded base-pairs, L about 11, and M about 13. On the other hand, fragment N is found to have only three weak G-C pairs. For both L + N and M + N, 15-17 strong base pairs are found. The observations give direct support to the clover-leaf structure and at the same time provide information on the stability of each of the four arms in the structure.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100407
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  • 3
    Electronic Resource
    Electronic Resource
    Strategy for the synthesis of large peptides: An application to the total synthesis of human parathyroid hormone [hPTH(1-84)] (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 1823-1832 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A strategy suitable for the synthesis of larger peptides is proposed. It involves the following four considerations: (1) all of the side-chain functional groups are protected by benzyl-type protective groups; (2) a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, is used for the fragment-condensation reactions together with 1-hydroxybenzotriazole as the additive; (3) all the protective groups are cleaved simultaneously by the HF method in the final stage of the synthesis; and (4) side products formed are detected and removed by an efficient high-performance liquid chromatography procedure. The usefulness of these procedures is demonstrated taking the synthesis of human parathyroid hormone [hPTH(1-84)] as an example.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360200907
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  • 4
    Electronic Resource
    Electronic Resource
    1.4-Dipolare Cycloadditionen, II. Dreikomponenten-Reaktionen des Isochinolins mit Acetylendicarbonsäureester und verschiedenen Dipolarophilen (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1094-1106 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Läßt man Acetylendicarbonsäure-dimethylester in niedriger Stationärkonzentration mit lsochinolin in Gegenwart von Phenylisocyanat, Mesoxalsäure-diäthylester oder Azodicarbonsäureester reagieren, gelangt man zu 1: 1: 1-Cycloaddukten der drei Komponenten (4, 15, 20), die strukturell geklärt werden. Der aus Isochinolin und Acetylendicarbonester gebildete 1.4-Dipol vereinigt sich dabei mit den genannten Dipolarophilen. Ein zweistufiger Mechanismus der 1.4-Cycloaddition wird wahrscheinlich gemacht. Unter Pyridin-Katalyse tritt Acetylendicarbonester mit Phenylisocyanat zu einem Tetrahydropyrimidin-Derivat (25) (1 : 2-Addukt) zusammen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000406
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  • 5
    Electronic Resource
    Electronic Resource
    1.4-Dipolare Cycloadditionen, V. Einige Umsetzungen des 3.4-Dihydro-isochinolins mit elektrophilen CC-Mehrfachbindungen (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1616-1620 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nach dem üblichen Schema vereinigt sich 3.4-Dihydro-isochinolin mit N-Phenyl-maleinimid zu einem säurelabilen 2:1-Addukt. Mit Popiolsäure-methylester gelangt man je nach Stöchiometrie zu 1:2- bzw. 2:1-Addukten. Gleichem strukurellem Typ wie obige 2:1-Addukte entspricht dasjenige aus Dihydroisochinolin un Hexafluor-butin-(2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000528
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  • 6
    Electronic Resource
    Electronic Resource
    1.4-Dipolare Cycloadditionen, IV. Reaktionen der Azomethine mit Isothiocyanaten und Schwefelkohlenstoff (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1602-1615 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die reversible 2:1-Cycloaddition von Benzyliden-alkylaminen oder 3.4-Dihydro-isochinolin and Senföle führt zu Hexahydro-s-triazin-thion-Derivaten, die Addition an Schwefelkohlenstoff zu Hydro-1.3.5-thiadiazin-thionen. Benzyliden-methylamin vereinigt sich mit Benzoylsenföl zu einem gelben Diels-Alder-Addukt. Der 1.4-Dipol aus Isopropyliden-isopropylamin and Schwefelkohlenstoff stabilisiert sich durch 1.5-Protonenverschiebung und Folgereaktionen zu einem Thiazolinthion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000527
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  • 7
    Electronic Resource
    Electronic Resource
    Operator formalism for forming ket vectors under some constraints (1975)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 9 (1975), S. 969-973 
    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: Reformulation, generalization, and application of Löwdin's symmetric orthonormalization, of orthogonalization of two sets of vectors, and of McWeeny's variational method of a density matrix, etc., by means of an operator for forming ket vectors on which are imposed some conditions, are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560090604
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  • 8
    Electronic Resource
    Electronic Resource
    Maximum and minimum overlap, localized, and hybrid orbitals for atoms and molecules by means of orthonormality-constrained variation (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 13 (1978), S. 199-206 
    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 shown that application of the orthonormality-constrained variation method to the absolute squares of three kinds of overlap integrals leads to eigenvalue equations and of which the eigenvectors belonging to maximum (minimum) eigenvalues are the maximum (minimum) overlap, localized, and hybrid orbitals. In the eigenvalue equations, coupling operators similar to those used in SCF theory are found to occur. Connection of the maximum orbitals to a many-shell model, a simple MO theory, and Löwdin's orthonormalization is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560130205
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  • 9
    Electronic Resource
    Electronic Resource
    Metric-constrained variation method for atoms and molecules (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 14 (1978), S. 313-318 
    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 method is presented for the variational calculation of a set of vectors under the condition that the metric of the vectors remains unchanged through the process of variation. Application of this method to typical measures (energy, overlap, distance, etc.) in quantum chemistry gives rise to new variational equations, for which the solution yields the Löwdin symmetric orthonormalization, the Kashiwagi-Sasaki generalization, the symmetric deorthogonalization, and the Adams localization, etc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560140309
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Chemical Transformations of 1,3-Diaryltetrazolium Salts. Preparation of Mercury(II) and Palladium(II) Complexes of 1,3-Diaryltetrazolylene and Reactions of 5-Substituted 1,3-Diphenyltetrazolium Salts with Nucleophiles (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1149-1155 
    Details
    ISSN: 0009-2940
    Keywords: Mesoionic compounds ; Tetrazolium salts, 1,3-diaryl- ; Carbenes, mesoionic ; Carbene-metal complexes ; Nucleophilic substitution ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Diaryltetrazolium salts 5 and 6 have been prepared by nitric acid oxidation of the corresponding 5-thiolates 4. The reaction of 5 with mercury(II) acetate gives (1,3-diaryltetrazolylene)mercury(II) complexes 7, which provide 5-halotetrazolium salts 8 - 10 by treatment with halogen. 1,3-Diphenyltetrazolylene (16), generated in situ by proton abstraction of 1,3-diphenyltetrazolium salts 5a or 6a, has been trapped with p-(dimethylamino)benzenediazonium tetrafluoroborate to form 18/18′. The palladium(II) complex 19 of 1,3-diphenyltetrazolylene has been prepared by oxidative addition of tetrakis(triphenylphosphane)palladium(0) to 5-chlorotetrazolium salt 8. The reactivity of various 5-substituted tetrazolium salts toward carbon nucleophiles depends on the nature of the substituents at C-5. With electronegative substituents, nucleophilic substitution proceeds at C-5, whereas electron-donating substituents direct the nucleophiles towards N-2 yielding ring-cleaved products.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260514
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