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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Perspectives in drug discovery and design 9-11 (1998), S. 3-17 
    ISSN: 1573-9023
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-8854
    Keywords: Diastereomeric salts ; O, O′-di-p-toloyl hydrogen tartrates ; crystal packing ; molecular mechanics calculations ; conformational analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structures of a pair of diastereomeric salts of (−)-(2R, 3R)-O, O′-di-p-toloyl tartaric acid and (−)- and ( + )-3-N,N-dimethylamino-1,1-diphenyl-1-butanol have been determined. Crystal data: 3: (-)-(R)-C18HC24NO+(-)-(2R,3R)-C20H17O- 8 orthorhombic, P212121, a = 7.873(2), b = 15.343(3), c = 28.76(1) Å, V = 3474(2) Å3, Z = 4, and D calc = 1.254 g cm−3. 4: (+)- (S)-C18H24NO+, (-)-(2R,3R)-C20H17O- 8orthorhombic, P212121, a = 7.504(1), b = 17.215(2), c = 26.490(4) Å, V = 3422.0(8) Å3,Z = 4, and D calc = 1.273 g cm−3. The geometries and the conformational energies of the solid state conformations of the cations have been compared with global and local energy minimum conformations determined by molecular mechanics calculations. In the solid state, one conformation with and one without an intramolecular hydrogen bond are observed. The calculated global energy minimum conformation in aqueous solution contains the intramolecular hydrogen bond.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer aided molecular design 12 (1998), S. 383-383 
    ISSN: 1573-4951
    Keywords: AMBER ; bioactive conformation ; conformational analysis ; GB/SA hydration model ; ligand–protein interactions ; MM3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The conformational energies required for ligands to adopt their bioactive conformations were calculated for 33 ligand–protein complexes including 28 different ligands. In order to monitor the force field dependence of the results, two force fields, MM3 and AMBER, were employed for the calculations. Conformational analyses were performed in vacuo and in aqueous solution by using the generalized Born/solvent accessible surface (GB/SA) solvation model. The protein-bound conformations were relaxed by using flat-bottomed Cartesian constraints. For about 70% of the ligand–protein complexes studied, the conformational energies of the bioactive conformations were calculated to be ≤3 kcal/mol. It is demonstrated that the aqueous conformational ensemble for the unbound ligand must be used as a reference state in this type of calculations. The calculations for the ligand–protein complexes with conformational energy penalties of the ligand calculated to be larger than 3 kcal/mol suffer from uncertainties in the interpretation of the experimental data or limitations of the computational methods. For example, in the case of long-chain flexible ligands (e.g. fatty acids), it is demonstrated that several conformations may be found which are very similar to the conformation determined by X-ray crystallography and which display significantly lower conformational energy penalties for binding than obtained by using the experimental conformation. For strongly polar molecules, e.g. amino acids, the results indicate that further developments of the force fields and of the dielectric continuum solvation model are required for reliable calculations on the conformational properties of this type of compounds.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer aided molecular design 14 (2000), S. 769-786 
    ISSN: 1573-4951
    Keywords: bioactive conformation ; conformational analysis ; dopamine D2 ; dopamine D4 ; D2/D4 selectivity ; enantioselectivity ; pharmacophore model ; solvation energies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A pharmacophore model for dopamine D4 antagonists has been developed on the basis of a previously reported dopamine D2 model. By using exhaustive conformational analyses (MM3* force field and the GB/SA hydration model) and least-squares molecular superimposition studies, a set of eighteen structurally diverse high affinity D4 antagonists have successfully been accommodated in the D4 pharmacophore model. Enantioselectivities may be rationalized by conformational energies required for the enantiomers to adopt their proposed bioactive conformations. The pharmacophore models for antagonists at the D4 and D2 receptor subtypes have been compared in order to get insight into molecular properties of importance for D2/D4 receptor selectivity. It is concluded that the bioactive conformations of antagonists at the two receptor subtypes are essentially identical. Receptor essential volumes previously identified for the D2 receptor are shown to be present also in the D4 receptor. In addition, a novel receptor essential volume in the D4 receptor, not present in the D2 receptor, has been identified. This feature may be exploited for the design of D4 selective antagonists. However, it is concluded that the major determinant for D2/D4 selectivity is the nature of the interactions between the receptor and aromatic ring systems. The effects of the electronic properties of these ring systems on the affinities for the two receptor subtypes differ substantially.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer aided molecular design 1 (1987), S. 143-152 
    ISSN: 1573-4951
    Keywords: Molecular graphics ; Conformational analysis ; Molecular mechanics ; Dopamine receptor agonists
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A series of apomorphine congeners has been studied with respect to their ability to mimic the structural requirements of the dopamine pharmacophore in the potent and stereoselective dopamine receptor agonist (R)-apomorphine. Conformational energies of the mimicking structures calculated by molecular mechanics (MMP2) correlate well with the observed biological activities.
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  • 6
    ISSN: 1573-1561
    Keywords: Structure-activity relationships ; single-cell recordings ; turnip moth ; Agrotis segetum ; Lepidoptera ; Noctuidae ; molecular shape ; dipole moments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The response of an antennal receptor cell of the turnip moth,Agrotis segetum, was recorded during stimulation with a series of (Z)-7-dodecenyl acetate analogs with structural variations of the acetate group. The investigated receptor cell is known to be highly selective to (Z)-7-dodecenyl acetate. All parts of the acetate group were found to be of great importance for full biological activity. The results indicate very strict requirements on the shape of the polar functional group, as well as on its electron distribution for a successful interaction with the antennal receptor cell.
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  • 7
    ISSN: 1573-1561
    Keywords: Structure-activity ; single-sensillum recordings ; receptor interaction ; pheromone ; (Z)-5-decenyl acetate ; alkenyl cuprate ; alkyl substitution ; Agrotis segetum ; Lepidotera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Structure-activity relationships for 6-, 7-, 8-, and 9-alkyl substituted analogs of (Z)-5-decenyl acetate, a pheromone component of the turnip moth,Agrotis segetum, have been studied by electrophysiological single-sensillum recordings, and interpreted in terms of a receptor-interaction model. The compounds were prepared by alkenyl cuprate reactions withα,β-unsaturated carbonyl derivatives or alkyl halides. The electrophysiological results indicate steric repulsive interactions between the alkyl groups and the receptor in all the positions studied. This demonstrates a high complementarity between the receptor and the terminal alkyl chain.
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  • 8
    ISSN: 1573-1561
    Keywords: Lepidoptera ; noctuidae ; Agrotis segetum ; (Z)-5-decenyl acetate ; pheromone analogue ; halides ; structure-activity ; single-sensillum ; recordings ; receptor-interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Analogs of (Z)-5-decenyl acetate, a pheromone component of the turnip moth,Agrotis segetum, with a chloro, bromo, or iodo substituent in place of the terminal methyl group have been synthesized and tested by electrophysiological single-sensillum recordings. The electrophysiological results have been interpreted in terms of substituent size and hydrophobicity. Interaction energies based on receptor interaction models have been calculated using the molecular mechanics [MM2(85)] method. The results support our previously suggested receptor interaction model in which the terminal alkyl chain interact with a complementary hydrophobic receptor “pocket” with very limited flexibility.
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  • 9
    ISSN: 1573-1561
    Keywords: Agrotis segetum ; Lepidoptera ; Noctuidae ; (Z)-5-decenyl acetate ; fluorinated analogs ; behavioral activity ; electrophysiological activity ; flight tunnel ; single sensillum recording ; field test ; lipophobicity ; lipid solubility ; structure-activity analysis ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The electrophysiological and behavioral responses of maleAgrotis segetum to fluorinated analogs of (Z)-5-decenyl acetate (Z5-10∶OAc) were investigated. The single sensillum recordings showed that 4,4-difluoro-(Z)-5-decenyl acetate (4,4-F2), 7,7-difluoro-(Z)-5-decenyl acetate (7,7-F2), 10,10,10-trifluoro-(Z)-5-decenyl acetate (10,10,10-F3) and 7,7,8,8-tetrafluoro-(Z)-5-decenyl acetate (7,7,8,8-F4) were each 100-fold less active than the natural Z5-10 ∶ OAc, whereas the 7,7,8,8,9,9,10,10,10-nonafluoro-(Z)-5-decenyl acetate (F9) analog was essentially inactive. A mixture of Z5-10 ∶ OAc, Z7-12 ∶ OAc, and Z9-14 ∶ OAc on a filter paper dispenser was as attractive as female gland extracts when tested in a flight tunnel. With Z5-10∶OAc omitted, the two-component mixture elicited a significantly lower male response. Four analogs, 7,7-F2, 10,10,10-F3, 7,7,8,8-F4, and F9, were added separately to the two-component mixture to replace Z5-10∶OAc. The responses elicited by the mixtures containing the 7,7-F2, 10,10,10-F3, and 7,7,8,8-F4 analogs did not differ significantly from that of the natural three-component mixture and the two-component mixture, whereas the mixture containing F9 elicited a significantly lower male response, as low as the response to the two-component mixture. In a field test the mixtures containing 10,10,10-F3 and 7,7,8,8-F4 were significantly more active than the two-component mixture, but still less active than the natural three-component mixture. It appears that field tests provided greater discrimination among pheromone analogs in assessing their behavioral activity than the flight-tunnel test did. Structure-activity analyses demonstrate the importance of the lipophilic interaction between the terminal alkyl chain and the receptor site for the activity of the stimulus. The lipophobicity of the fluorinated analogs impedes a productive receptor interaction.
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  • 10
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Noctuidae ; Agrotis segetum ; (Z)-5-decenyl acetate ; pheromone analogs ; structure-activity ; chain-elongated analogs ; enol ethers ; alkyl ethers ; single-sensillum recordings ; receptor interaction ; molecular mechanics ; MM2 ; MM3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In order to test a previous conclusion that chain-elongated analogs of (Z)-5-decenyl acetate(1), a pheromone component of the turnip moth,Agrotis segetum, adopt a loop conformation of the terminal alkyl chain in the bioactive conformation, a series of alkyl ether and enol ether analogs of1 and (Z)-5-dodecenyl acetate(2) have been synthesized and tested using singlecell electrophysiology. In these analogs a methylene group in positions 7 and 9 of1 and in positions 7 and 11 in2 have been replaced by an oxygen atom in order to energetically facilitate the formation of a loop conformation in the chain-elongated analogs. The electrophysiological results in combination with molecular mechanics (MM2 and MM3) calculated conformational energies show that the activity decreases of the chain-elongated ether analogs are significantly smaller than that for2 and that these activity decreases parallel the conformational energies for a loop formation of the terminal chains in the analogs. The results support our previous conclusion that the terminal chain of chain-elongated analogs of1 adopts a loop conformation in their bioactive conformations.
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