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Two steroids, 3-oxo-chol-4-ene-24-oic acid (2) andi ts unsaturated analog 4 have been isolated from the dorid nudibranch Aldisasanguineacooperi, and the acid 2 has been shown to have antifeedant properties.  相似文献   

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Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort Plagiochilaacanthophylla subsp. japonica and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis.  相似文献   

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The structure of koumine, an indole alkaloid from Gelsemiumelegans Benth., was determined by a X-ray crystallographic study.  相似文献   

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The new compounds 14 and 8 have been isolated from cultures of Aspergillusduricaulis  相似文献   

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All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.  相似文献   

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A new ichthyotoxic toxin was isolated from the unialgal culture of the deleterious Florida red tide organism, Gymnodiniumbreve Davis (Syn. Ptychodiscusbrevis), and its structure was elucidated.  相似文献   

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Sterepolide and dihydrosterepolide, new sesquiterpenes isolated from the fungus Stereumpurpureum, are assigned structures 4 and 7, respectively. The assignments are based mainly on spectroscopic studies and similarities to isolactarorufin (5). A possible mode of biogenesis of these isolactarane type sesquiterpenes is discussed.  相似文献   

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The structures of alkaloid-A and -B were established via X-ray crystallography of the former as its HI salt, and its chemical conversion to the latter.  相似文献   

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Head space analysis, GLC retention time data, and solution calorimetry are used to determine the effect of medium on the thermodynamic parameters for the equilibrium (1) ? (2). It is shown that changes in ΔG° and ΔH° can be evaluated for the transfer of the equilibrium from a series of solvents to the gaseous phase which is used as the reference medium.  相似文献   

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