- Synthesis of (S)-(-)-austrocorticin and (S)-(+)-dermolactone: Absolute stereochemistry of the natural products
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The anthraquinones (S)-(-)-austrocorticin (9) and (S)-(+)-dermolactone (2) are synthesised using the chiral dienes 6a and 6b, respectively; comparison with these synthetic compounds establishes that natural austrocorticin has the (R) absolute configuration while dermolactone occurs naturally as a mixture of enantiomers in which the (S) isomer predominates.
- Cotterill,Gill
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- Synthesis of E-Alkyl Alkenes from Terminal Alkynes via Ni-Catalyzed Cross-Coupling of Alkyl Halides with B-Alkenyl-9-borabicyclo[3.3.1]nonanes
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The first Ni-catalyzed Suzuki-Miyaura coupling of alkyl halides with alkenyl-(9-BBN) reagents is reported. Both primary and secondary alkyl halides including alkyl chlorides can be coupled. The coupling method can be combined with hydroboration of termina
- Di Franco, Thomas,Epenoy, Alexandre,Hu, Xile
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supporting information
p. 4910 - 4913
(2015/10/12)
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- Highly regioselective opening of zirconacyclopentadienes by remote coordination: Concise synthesis of the furan core of the leupyrrins
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An efficient protocol for the highly regioselective opening of aliphatic zirconacyclopentadienes is reported. The one-pot process involves a zirconocene-mediated cyclization of 1,6-diynes and highly selective cleavage of the metallacycles with NBS and enables a concise synthesis of the tetrahydrofuran-core of the leupyrrins.
- Debnar, Thomas,Dreisigacker, Sandra,Menche, Dirk
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supporting information
p. 725 - 727
(2013/02/25)
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- Method for the efficient synthesis of highly-substituted oxetan- and azetidin-, dihydrofuran- and pyrrolidin-3-ones and its application to the synthesis of (±)-pseudodeflectusin
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Highly substituted four- and five-membered heterocycles were prepared starting with O,P- and N,P-acetals by using a one-pot method involving base induced cyclization and a Horner-Wadsworth-Emmons (HWE) olefination reaction. Divergent synthesis of various heterocycles was achieved by using this method and transformations of the alkenyl group in the products of these processes were exemplified. Finally, a short and efficient synthesis of (±)- pseudodeflectusin based on the new methodology was achieved.
- Maegawa, Tomohiro,Otake, Kazuki,Hirosawa, Keiichi,Goto, Akihiro,Fujioka, Hiromichi
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supporting information
p. 4798 - 4801
(2013/01/15)
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- COMPOUNDS AND COMPOSITIONS USEFUL IN THE TREATMENT OF NEOPLASIA
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There is described compounds for use in therapy, said compounds being defined by Formula (1): There is also described an anti-proliferative composition comprising one or more compounds according to Formula (1), and a method of treatment of neoplasia comprising the administration of such a compound or composition.
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Page/Page column 49; 62-63
(2008/06/13)
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- (Z,Z)-4,7-tridecadien-(S)-2-YL acetate: Sex pheromone of Douglas-fir cone gall midge, Contarinia oregonensis
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Our objectives were to identify and field test the sex pheromone of female Douglas-fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae). Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of pheromone extract revealed a single compound (A) that elicited responses from male antennae. Hydrogenation of pheromone extract, followed by renewed GC-EAD analysis, revealed a new EAD-active compound with chromatographic characteristics identical to those of tridecan-2-yl acetate on five fused silica columns (DB-5, DB-210, DB-23, SP-1000, and Cyclodex-B). Syntheses, chromatography, and retention index calculations of all possible tridecen-2-yl acetates suggested that the candidate pheromone A was a tridecadien-2-yl acetate with nonconjugated double bonds. Synthetic candidate pheromone component (Z,Z)-4,7-tridecadien-2-yl acetate (Z4Z7) cochromatographed with A on all analytical columns and elicited comparable antennal activity. In GC-EAD analyses that separated the enantiomers (Z,Z)-4,7-tridecadien-(S)-2-yl acetate (2S-Z4Z7) and (Z,Z)-4,7-tridecadien-(R)-2-yl acetate (2R-Z4Z7) with baseline resolution, only 2S-Z4Z7 as a component in a racemic standard or in pheromone extract elicited antennal responses. In Douglas-fir seed orchards, sticky traps baited with 2S-Z4Z7 captured male C. oregonensis, whereas 2R-Z4Z7 was behaviorally benign. Comparable catches of males in traps baited with racemic Z4Z7 (50μg) or virgin female C. oregonensis suggested that synthetic pheromone baits could be developed for monitoring C. oregonensis populations in commercial Douglas-fir seed orchards.
- Gries, Regine,Khaskin, Grigori,Gries, Gerhard,Bennett, Robb G.,King, G.G. Skip,Morewood, Petra,Slessor, Keith N.,Morewood, W. Dean
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p. 2283 - 2297
(2007/10/03)
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- Identification of a Novel Moth Sex Pheromone in Eriocrania cicatricella (Zett.) (Lepidoptera: Eriocraniidae) and its Phylogenetic Implications
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Extracts from different body parts of adult female Eriocrania cicatricella (Zett.) were tested for electrophysiological activity on conspecific male antennae. Extracts from the Vth abdominal segment, containing a pair of exocrine glands, elicited the largest electroantennographic response when compared to extracts of other body parts. Female extracts were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). The EAD active peaks were identified as (Z)-4-hepten-2-one, (2R)-heptane-2-ol, and (2R)-(Z)-4-hepten-2-ol by coinjection on a gas chromatography and by comparison of mass spectra with those of synthetic standards. In field tests, a blend of these three pheromone components was highly attractive to conspecific males, and a subtractive assay confirmed that the unsaturated alcohol is the major pheromone component, whereas no definite behavioral activity could be assigned to the ketone or the saturated alcohol. A bait containing the two alcohols with S-configuration was attractive to male E. sparrmanella (Bosc), whereas no males of E. cicatricella were found in these traps. The sex pheromone compounds in E. cicattricella are chemically similar to pheromones reported in Trichoptera and they are produced in homologous glands.
- Zhu, Junwei,Kozlov, Mikhail V.,Philipp, Peter,Francke, Wittko,Loefstedt, Christer
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- Pigments of fungi. Part 41. Synthesis of (S)-(+)- and (+/-)-dermolactone; stereochemistry of dermocactone from the Australian fungus Dermocybe sanguinea (Wulf. ex Fr.) Wuensche sensu Cleland
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(S)-(+)-Dermolactone 3 has been synthesised in monochiral form beginning with ethyl (S)-lactate, the tetracyclic nucleus being assembled by way of a regiospecific cycloaddition between the known chloronaphthoquinone 15 and the novel, highly functionalised chiral butadiene 5.Isochiral dermolactone 3 + 4 is prepared in the same way from (+/-)-5.Dermolactone, as it occurs naturally, is shown by 1H NMR shift experimants on the corresponding permethyl ethers 25 and 27, using , to consist of an anisochiral mixture of the (S)-(+)- and (R)-(-)-enantiomers 3 and 4, respectively, in which the former predominates in the ratio of 1.8:1 (28.6percent ee).
- Cotterill, Ann S.,Gill, Melvyn,Milanovic, Nives M.
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p. 1215 - 1224
(2007/10/02)
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- Synthesis of a Pyranonaphthoquinone-spiroacetal
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A synthesis of pyranonaphthoquinone-spiroacetal 12 is reported which represents an efficient entry to the pentacyclic framework of the pyranonaphthoquinone antibiotic griseusin A.The key step involves assembly of the furonaphthopyran 11 via a ceric ammonium nitrate oxidative rearrangement of the furonaphthofuran 10.This latter heterocycle 10 in turn was constructed via the uncatalysed 1,4-addition of 2-trimethylsilyloxyfuran 9 to naphthoquinone 8.Naphthoquinone 8 is readily available from 1,4-dimethoxynaphthalene-2-carbaldehyde 3 and acetylene 4.
- Brimble, Margaret A.,Nairn, Michael R.
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p. 579 - 584
(2007/10/02)
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