- Novel antifeedant and insecticidal compounds from avocado idioblast cell oil
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Several insecticidal compounds have been identified by bioassaydriven fractionation of avocado, Persea americana Mill, idioblast cell oil. A flash chromatography fraction of the oil showed substantial toxicity to early instars of the generalist insect herbivore, Spodoptera exigua (Hubner) (100% mortality after seven days). Following further fractionation, five biologically active compounds, 2-(pentadecyl)furan, 2-(heptadecyl)furan, 2-(1E-pentadecenyl)furan, 2-(8Z, 11Z-heptadecadienyl)furan, and the triglyceride triolein, were identified. Several minor components were also tentatively identified, including 2-(1Z-pentadecenyl)furan, 2-(1E-heptadecenyl)furan, and 2-(1E,8Z, 11Z-heptadecatrienyl)furan. Several 2-alkylfurans of this type have been reported previously from avocado (Persea spp.) and have received the common name of avocadofurans. The major compounds were tested individually for toxic and growth inhibitory effects. Individually, the compounds had low to moderate toxicity. Of these, 2-(pentadecyl)furan had the greatest effects, with an LC50 value of 1031 μg/g. At concentrations of 600 μg/g or higher in diets, larval growth was inhibited by >70% compared to controls. The analogous 2-(heptadecyl)furan had an LC50 value of 1206 μg/g, and also significantly reduced larval growth (>75% versus controls) at concentrations of > 600 μg/g. The unsaturated analogs 2-(1E-pentadecenyl)furan and 2-(8Z, 11Z-heptadecadienyl)furan were less toxic. Triolein was only weakly toxic, with an LC50 value of 10,364 μg/g diet. Larval growth was inhibited only at concentrations of 7000 μg/g or higher. The potential of avocadofurans in insect control is discussed.
- Rodriguez-Saona, Cesar,Millar, Jocelyn G.,Maynard, David F.,Trumble, John T.
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p. 867 - 889
(2007/10/03)
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- The Stereochemistry of the Tetrabromides from Linoleic Acid
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The stereochemistry of the crystalline 9,10,12,13-tetrabromostearic acid obtained by bromination of linoleic acid has been established by X-ray crystallographic analysis.The structures of the corresponding oily tetrabromide, and of the two derived 1,8,9,11,12-pentabromoheptadecanes, follow.
- Carman, Raymond M.,Duffield, Alan R.,Edwards, Ross A.,Robinson, Ward T.
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p. 1495 - 1502
(2007/10/02)
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- Synthesis of the Avocado Antifungal, (Z,Z)-2-Hydroxy-4-oxohenicosa-12,15-dien-1-yl Acetate
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A synthesis of the avocado antifungal, (Z,Z)-2-hydroxy-4-oxohenicosa-12,15-dien-1-yl acetate (la), confirms the structure of the compound as isolated from both avocado fruit and leaves, and provides the absolute configuration of the natural lipid.
- Bull, Steven D.,Carman, Raymond M.
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p. 1661 - 1672
(2007/10/02)
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- RETENTION OF CONFIGURATION IN DOUBLE BOND PROTECTION-DEPROTECTION BY BROMINATION-CATHODIC DEBROMINATION
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The double bond can be mildly protected by bromination with PyHBr3; deprotection is achieved by cathodic reduction at -1.4 V.The overall yields range from 68 to 99 percent, the configuration of the double bond is retained with at least 96 percent.
- Husstedt, Urda,Schaefer, Hans J.
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p. 623 - 624
(2007/10/02)
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