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Synthesis of Polyamine Analoga of Spider Toxins Within the last few years, polyamine toxins derived from various arthropods raised increasing interest due to their interaction with glutamate receptors of insects and invertebrates. Compounds 51 and 52 (Scheme 5) were prepared together with 53–58 to study a new pathway to Ala-, Lys-, and Gln-derived polyamine toxins according to Scheme 6.  相似文献   

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Synthesis of Betenamine and of Betalaine Model Substances For comparisons of color, spectroscopic properties, pKa values, and stabilities, a number of model substances containing the 1,7-diazaheptamethinium chromophore 8 of the yellow and red betalaine plant pigments were prepared by the thermal or photolytic ring opening of simple pyridine derivatives (such as 2 and 14-16 ), followed by the introduction of amines. Among the novel compounds prepared were betenamine perchlorate ( 5 ), the ‘naked’ ring system of the beet-pigment betanine ( C ) as well as two 1,7-diazaheptamethinium salts 25 and 27 with terminal amono acids. The synthesis of 5 started with 4-(2-aminoethyl)pyridine ( 1 ) and proceeded via 2 , ring opening with indoline to 4 , saponification, and intramolecular amine replacement (Scheme 1). The syntheses of 25 and 27 involved only one step, namely ring opening of γ-picoline using (S)-cyclodopa ( 24 ) and (S)-proline ( 26 ), respectively (Scheme 3).  相似文献   

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A force field constructed for bile pigments and parametrized on partial structures of bile pigments was used to calculate the minimum energy geometries of diastereomeric bilatrienes-abc. In addition the relative energies of these isomers were deduced and the energies of interconversion between the mirror images of the more or less helical (Z,Z,Z)-syn, syn, syn-form were calculated for various paths.
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