- Long-Chain Alkyl Cyanides: Unprecedented Volatile Compounds Released by Pseudomonas and Micromonospora Bacteria
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The analysis of volatiles from bacterial cultures revealed long-chain aliphatic nitriles, a new class of natural products. Such nitriles are produced by both Gram-positive Micromonospora echinospora and Gram-negative Pseudomonas veronii bacteria, although the structures differ. A variable sequence of chain elongation and dehydration in the fatty acid biosynthesis leads to either unbranched saturated or unsaturated nitriles with an ω?7 double bond, such as (Z)-11-octadecenenitrile, or methyl-branched unsaturated nitriles with the double bond located at C-3, such as (Z)-13-methyltetradec-3-enenitrile. The nitrile biosynthesis starts from fatty acids, which are converted into their amides and finally dehydrated. The structures and biosyntheses of the 19 naturally occurring compounds were elucidated by mass spectrometry, synthesis, and feeding experiments with deuterium-labeled precursors. Some of the nitriles showed antimicrobial activity, for example, against multiresistant Staphylococcus aureus strains.
- Montes Vidal, Diogo,von Rymon-Lipinski, Anna-Lena,Ravella, Srinivasa,Groenhagen, Ulrike,Herrmann, Jennifer,Zaburannyi, Nestor,Zarbin, Paulo H. G.,Varadarajan, Adithi R.,Ahrens, Christian H.,Weisskopf, Laure,Müller, Rolf,Schulz, Stefan
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- Cycloaddition Reactions of Cobalt-Complexed Macrocyclic Alkynes: The Transannular Pauson-Khand Reaction
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The Pauson-Khand reaction is a powerful tool for the synthesis of cyclopentenones through the efficient [2 + 2 + 1] cycloaddition of dicobalt alkyne complexes with alkenes. While intermolecular and intramolecular variants are widely known, transannular versions of this reaction are unknown and the basis of this study. Macrocyclic enyne and dienyne complexes were readily synthesized by palladium(II)-catalyzed oxidative macrocyclizations of bis(vinyl boronate esters) or ring-closing metathesis reactions followed by complexation with dicobalt octacarbonyl. Several reaction modalities of these macrocyclic complexes were uncovered. In addition to the first successful transannular Pauson-Khand reactions, other intermolecular and transannular cycloaddition reactions included intermolecular Pauson-Khand reactions, transannular [4 + 2] cycloaddition reactions, intermolecular [2 + 2 + 2] cycloaddition reactions, and intermolecular [2 + 2 + 1 + 1] cycloaddition reactions. The structural and reaction requirements for each process are presented.
- Karabiyikoglu, Sedef,Boon, Byron A.,Merlic, Craig A.
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p. 7732 - 7744
(2017/08/14)
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- Silicon-containing polyphilic bent-core molecules: The importance of nanosegregation for the development of chirality and polar order in liquid crystalline phases formed by Achiral molecules
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Polyphilic molecules composed of a bent aromatic core, oligo(siloxane) units, and alkyl segments were synthesized, and the self-organization of these molecules was investigated. Most materials organize into polar smectic liquid crystalline phases. The swi
- Keith, Christina,Reddy, R. Amaranatha,Hauser, Anton,Baumeister, Ute,Tschierske, Carsten
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p. 3051 - 3066
(2007/10/03)
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- INSECT PHEROMONES AND THEIR ANALOGUES XL. SYNTHESIS OF DODEC-3Z-EN-11RS-OLIDE (FERRULACTONE II - A RACEMIC ANALOGUE OF A COMPONENT OF THE AGGREGATION PHEROMONE OF Cryptolestes ferrugineus
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A new route, based on the partial ozonolysis of ω-acetyl derivatives of alk-1-en-4-ynes, is proposed for the synthesis of 11RS-hydroxydodec-3Z-enoic acid, the cyclization of which gives dodec-3Z-en-11RS-olide (ferrulactone II) - a racemic analogue of one of the macrolide components of the aggregation pheromone of the rust-red grain beetle.
- Odinokov, V. N.,Ishmuratov, G. Yu.,Botsman, L. P.,Vakhidov, R. R.,Ladenkova, I. M.,et al.
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p. 369 - 374
(2007/10/02)
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