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  • 1
    Electronic Resource
    Electronic Resource
    Molecular structure of 2,3-(4′-phenylacetyl)- and 2,3-(4′-diphenylacetyl)-benzo-15-crown-5 (1991)
    Springer
    Russian chemical bulletin 40 (1991), S. 1609-1614 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The conformational state of two benzo-crown ethers with substantially different physiological activity, 2,3-(4′-phenylacetyl)- and 2,3-(4′-diphenylacetyl)benzo-15-crown-5, was studied in crystals and solutions in CH3CN and CCl4 by x-ray crystallographic analysis, IR spectroscopy, and conformational calculations by the method of molecular mechanics. Transition from the crystalline state to solutions was found to be accompanied by a substantial change in the conformation of the macrocyclic ring of all the compounds studied. The nature of the substituent in the benzene ring and the polarity of the solvent have an influence on the conformational state of the macrocyclic ring of the free ligand, which, however, is not the determining factor in the change in the activity of the compounds. The COCCOC fragments of the macrocyclic framework are conformationally labile, readily passing from gauche to trans conformations and the reverse, which is promoted by the negligible energy barriers between the different conformations, determined in the work by a molecular mechanics method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01172262
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and structure of diastereomeric trans-3,4-diamino-2,2,6,6-tetramethylpiperidine1-oxyl derivatives (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 328-333 
    Details
    ISSN: 1573-9171
    Keywords: trans-3.4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl ; diastereomeric derivatives, resolution ; structure ; absolute configuration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reaction of 3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl with (1S)-(+)-camphor-10-sulfonyl chloride gives a mixture of diastereomeric 4-monosulfonylamino derivatives. The products of their acylation have been obtained. The 3,4-bis-[(1S)-camphor-10-sulfonylamino] derivative was synthesized and resolved to individual diastereomers. For one of them thetrans relationship of the 3- and 4-substituents and the absolute (3S,4R)-configuration were established by X-ray structural analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697088
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  • 3
    Electronic Resource
    Electronic Resource
    Structure and properties of diphenylacetylbenzo-12-crown-4 (1989)
    Springer
    Russian chemical bulletin 38 (1989), S. 1857-1860 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It has been shown by x-ray structural examination and IR spectroscopy that conformations of diphenylacetylbenzo-12-crown-4 in which the lone pairs of oxygen are oriented on opposite sides of the plane of the macrocycle are stabilized in the crystal and in solution. From a comparison with the structure and anticonvulsant activity of benzo-12-crown-4 with those of its acetyl and diphenylacetyl derivatives, it is suggested that a condition for the possition of this type of activity is the presence of a conformation of the macrocycle in which the lone pairs of the three oxygen atoms are located on the same side.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00957777
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  • 4
    Electronic Resource
    Electronic Resource
    Conformational analysis of benzo-15-crown-5 and 2,3-(4′-benzoyl)benzo-15-crown-5 (1989)
    Springer
    Russian chemical bulletin 38 (1989), S. 748-753 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. An x-ray structure analysis has revealed substantial diferrences in the conformational states of 2,3-(4′-benzoyl)benzo-15-crown-5 and benzo-15-crown-5 in the crystal phase, differences related to realization of a trans-gauche-gauche' conformation in one COCCOC fragment in the 2,3-(4′-benzoyl)benzo-15-crown-5. 2. In nonpolar solvents, an equilibrium of several structures is realized in both compounds, an equilibrium with the participations of trans-gauche-trans, trans-gauche-gauche and trans-gauche-gauche' conformations. In a polar medium, there are no indications of the trans-gauch-gauche' conformation. 3. Upon complexation of the ligands with calcium thiocyanate in acetonitrile, there are spectral indications of complexes with differing stoichiometry, with a large contribution of the structure from trans-gauche-trans conformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00953285
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  • 5
    Electronic Resource
    Electronic Resource
    Macrocyclic amidophosphoryl polyethers: Biological activity, molecular structure, and structure of the complex with calcium thiocyanate (1992)
    Springer
    Russian chemical bulletin 41 (1992), S. 2211-2216 
    Details
    ISSN: 1573-9171
    Keywords: macrocyclic polyethers ; crystal structure ; biological activity ; IR spectra ; complex with calcium thiocyanate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The antihypoxic and anticonvulsant activity of eight new amidophosphoryl derivatives of crown ethers was investigated. It was found that some of them exhibit pronounced antihypoxic activity. The results of an x-ray structural and IR spectroscopic study of dibenzo-N-phenylphosphonyl-14-crown-5 (a=9.818,b=16.062,c=15.925 Å; γ=124.90°;V=2072 Å3;M=417.2;d=1.33 g/cm3 forZ=4, 1955 independent reflections [I〉3σ(I)] in a DAR-UM inCuK α radiation,P2 1/b space group,R=5.2%) and dibenzo-N-adamantylphosphonyl-14-crown-5 compounds (a=11.077,b=15.936,c=16.771 Å; γ=56.05°;V=2456 Å3;M=486.3;d=1.31 g/cm3 forZ=4, 2164 independent reflections [I〉3σ(I)] in a DAR-UM inCuK α radiation,P21/b space group,R=5.1%) are reported. Some details of the structure of the dibenzo-N-phenylphosphonyl-14-crown-5-complex with calcium thiocyanate and water are discussed; a polyhedron with a coordination number of six was found for the first time for calcium complexes with macrocyclic ligands. The combined examination of the results of the biological, x-ray structural, and IR spectroscopic study of macrocyclic, 14-member ligands suggested that the nature of the substituents at phosphorus affect the conformational state of the macrocycle, which remains unchanged in complexation in the investigated conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01150749
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  • 6
    Electronic Resource
    Electronic Resource
    Molecular structures of benzoylbenzo-12-crown-4 and diphenylacetylbenzo-12-crown-4 and possible reasons for different conformational states of their macrocycles (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 1821-1826 
    Details
    ISSN: 1573-9171
    Keywords: crown ethers ; molecular structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecular structures of (benzoyl)benzo-12-crown-4 (a=22.387,b=4.503,c=16.167 Å,d calc=1.34 g cm−3,Z=4, space groupP21 nc, DAR-UM, Cu-Kα,R=0.056) and (diphenylacetyl)benzo-12-crown-4 (a=8.866,b=23.337,c=10.737 Å;d calc=1.25 g cm−3,Z=4, space groupP212121, DAR-UM, Cu-Kα, R=0.056) have been investigated. The differences in the conformations of the macrocycles and the degree of conjugation between the benzene ring π orbitals and the lone pairs on the adjacent oxygen atoms in the macrocycle are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698995
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  • 7
    Electronic Resource
    Electronic Resource
    Probability of onset of brittle failure of vessels under pressure (1988)
    Springer
    Atomic energy 64 (1988), S. 230-238 
    Details
    ISSN: 1573-8205
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Notes: Conclusions The method proposed for determining the failure probability of pressurized vessels offers the possibility of quantitative comparison of the safety of different vessels in different operating conditions and estimating their failure probability overall. It may be further developed by replacing determinate characteristics by random characteristics. For example, that q is determinate in Eq. (1) means that the orientation of all the defects in the vessel relative to the largest principal stress is strictly constant. In practice, this means that q must be taken for the defect orientation which is worst from the viewpoint of strength; this makes the method excessively conservative. This may be eliminated if the probability density function of the crack orientation in space is introduced and used to calculate the distribution of values of the random parameter q.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01123131
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  • 8
    Electronic Resource
    Electronic Resource
    Probability of loss of hermetic sealing of fuel-element shells (1990)
    Springer
    Atomic energy 69 (1990), S. 703-709 
    Details
    ISSN: 1573-8205
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02047493
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  • 9
    Electronic Resource
    Electronic Resource
    Monitoring the metal of atomic-power-station pressure vessels and pipelines (1993)
    Springer
    Atomic energy 74 (1993), S. 353-358 
    Details
    ISSN: 1573-8205
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844620
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  • 10
    Electronic Resource
    Electronic Resource
    Chemical and x-ray structural investigation of a new diterpene lactone betolide (1988)
    Springer
    Chemistry of natural compounds 23 (1988), S. 673-678 
    Details
    ISSN: 1573-8388
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A crystalline substance with the composition C20H24O5 has been isolated from the roots of common betony. The spatial structure of this new diterpene lactone, betolide, has been established from the results of UV, IR, NMR, and13C NMR spectral and x-ray structural investigations — 13-formyl-14-hydroxy-(2′-hydroxy-5′-oxotetrahydrofuro) [3′,4′:11,12′]-Δ8,10,12-podocarpane, the first representative of new tetracyclic diterpenes the lactone ring of which is formed with the participation of a hydroxyl of a geminal diol. The stability of a lactone ring of this type and a high reactivity of the semiacetal hydroxyl have been shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00596641
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