- Divergent synthetic route to new cyclopenta[c]pyran iridoids: Syntheses of jatamanin A, F, G and J, gastrolactone and nepetalactone
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Six natural iridoids including jatamanin A, F, G and J, gastrolactone and nepetalactone have been synthesized via the efficient transformation of a core cyclopenta[c]pyran intermediate. Key features of the syntheses include the stereoselective construction of the core cyclopenta[c]pyran skeleton of the iridoid lactones via a Pd(0)-catalyzed intramolecular allylic alkylation, and the facile transformation of the common intermediate into natural iridoids.
- Sim, Jaehoon,Yoon, Inah,Yun, Hwayoung,An, Hongchan,Suh, Young-Ger
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- Simplified isolation procedure and interconversion of the diastereomers of nepetalactone and nepetalactol
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Three nepetalactones were isolated from Nepeta racemosa (mussinii) by traditional methods. An improved method was developed to isolate nepetalactones from N. faassenii. An epimerization procedure was used to prepare the fourth 7S-nepetalactone diastereomer. The cis-fused nepetalactols were prepared by reduction of the corresponding nepetalactones, while the trans-fused nepetalactols were unstable and found to undergo ring-opening reactions yielding iridodials. The characterizations and structural assignments by means of NMR agree with quantum chemical density functional calculations.
- Liblikas, Ilme,Santangelo, Ellen M.,Sandell, Johan,Baeckstroem, Peter,Svensson, Mats,Jacobsson, Ulla,Unelius, C. Rikard
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- Enantiospecific Synthesis of Nepetalactones by One-Step Oxidative NHC Catalysis
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An efficient oxidative NHC-catalyzed one-step transformation of (S)-or (R)-8-oxocitronellal to nepetalactone (NL) in enantio- A nd diastereomerically pure form has been developed. Several new and "easy to make" N-Mes-or N-Dipp-substituted 1,2,4-triazolium salts carrying nitroaromatic groups on N1 were synthesized and evaluated as precatalysts in combination with base and stoichiometric organic oxidant. Under optimized conditions, NLs are accessible in very good yields and diastereomerically pure under mild conditions. The oxidant used could be recovered and recycled under operationally simple conditions.
- Harnying, Wacharee,Neud?rfl, J?rg-M.,Berkessel, Albrecht
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p. 386 - 390
(2020/02/04)
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- Methods of separating ZE-nepetalactone and EZ-nepetalactone from catnip oil
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A method of separating ZE-nepetalactone and EZ-nepetalactone from catnip oil involving mixing catnip oil dissolved in at least one water immiscible, non-halogenated organic solvent with at least one inorganic base dissolved in water to form a biphasic mixture, stirring the biphasic mixture to hydrolyze ZE-nepetalactone to form ZE-nepetalic acid, separating the aqueous phase containing ZE-nepetalic acid from the organic phase containing EZ-nepetalactone in the biphasic mixture, and optionally acidifying the aqueous phase to about pH 4.5 and adding at least one water immiscible, non-halogenated organic solvent to azeotropically lactonize the ZE-nepetalic acid in the presence of a catalytic amount of p-toluene sulfonic acid to form ZE-nepetalactone.
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Page/Page column 3; sheet 2
(2008/06/13)
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- INSECT REPELLENT COMPOSITIONS COMPRISING DIHYDRONEPETALACTONE
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Dihydronepetalactone, a minor natural constituent of the essential oil of catmints (Nepeta spp.) such as Nepeta cataria, has been identified as an effective insect repellent compound. Synthesis of dihydronepetalactone may be achieved by hydrogenation of nepetalactone, the major constituent of catmint essential oils. This compound, which also has fragrance properties, may be used commercially for its insect repellent properties.
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Page/Page column 27-30
(2008/06/13)
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- The aphid sex pheromone cyclopentanoids: Synthesis in the elucidation of structure and biosynthetic pathways
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Identification of a range of aphid sex pheromones as comprising the cyclopentanoids (4aS,7S,7aR)-nepetalactone, (1R,4aS,7S,7aR)-nepetalactol and the (1S)- and (1R,4aR,7S,7aS)-nepetalactols required samples authenticated by 1H and 13C NMR. These and related compounds were provided by small scale synthesis and extraction from plants in the genus Nepeta (Lamiaceae). The subsequent discovery that the synthetic sex pheromones could attract males, and also parasitic wasps that attack aphids, has created a need for large scale syntheses of the cyclopentanoids. This is afforded by cyclisation of the 8-oxo-1-enamine of citronellal as originally developed by Schreiber and co-workers (1986). Investigation into the biosynthesis of the cyclopentanoids by plants for exploiting aphid sex pheromones in crop protection by means of molecular biology required synthesis of putative biosynthetic intermediates, some with radioactive isotopic labelling, particularly 8-oxidised monoterpene alcohols and aldehydes.
- Dawson, Glenn W.,Pickett, John A.,Smiley, Diane W. M.
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p. 351 - 361
(2007/10/03)
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- SYNTHESIS OF IRIDOLACTONES ISOLATED FROM SILVER VINE
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The naturally occurring iridolactones, nepetalactone, isodihydronepetalactone, and iridomyrmecin are synthesized in optically active forms starting from natural glycoside geniposide.The stereogenic centers were introduced with highly stereoselective hydrogenations.
- Kigawa, Masaharu,Tanaka, Masahide,Mitsuhashi, Hiroshi,Wakamatsu, Takeshi
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p. 117 - 120
(2007/10/02)
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- A New Conversion Method from (-)-Limonene to Nepetalactones
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This paper describes the conversion of (-)-limonene to four nepetalactones (1, 2, ent-3 and 4) in a stereocontrolled manner.The cis-3,4-disubstituted cyclopentanone (5) obtained from (-)-limonene via Rh(I)-catalyzed cyclization of the 4-pentenal, could be converted to the bicyclooctenone (6).After the stereoselective conversion of 6 into the diastereomeric isomers of the ketones (8 and 16), a sequence of reactions involving the silyl enol ethers (18 and 19), ozonolysis, and subsequent lactonization afforded the target molecules.Keywords - nepetalactone; cis,cis-dihydronepetalactone; dihydronepetalactone; cis,cis-nepetalactone; bicyclooctenone; (-)-limonene
- Suemune, Hiroshi,Oda, Kozo,Saeki, Seitaro,Sakai, Kiyoshi
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p. 172 - 177
(2007/10/02)
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- BIOSYNTHESIS OF NEPETALACTONE IN NEPETA CATARIA
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Iridodial is a key intermediate in the biosynthesis of nepetalactone.One of the steps on the pathway prior to the lactonization is a hydride shift from C-1 to C-10. 10-Hydroxycitronellol is a far more efficient precursor than the C-2/C-3 unsaturated analogue.Key Word Index -- Nepeta cataria; Labiatae; nepetalactone; iridane skeleton; monoterpene biosynthesis; hydride shift.
- Bellesia, Franco,Grandi, Romano,Pagnoni, Ugo M.,Pinetti, Adriano,Trave, Roberto
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