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Michel Lebœuf Diego Cortes Reynald Hocquemiller André Cavé Angèle Chiaroni Claude Riche 《Tetrahedron》1982,38(19):2889-2896
The structure of guoregine, a new isoquinoline alkaloid from , Annonaceae, has been deduced by spectral analysis and confirmed by an X-ray structure determination. It is the first member of a new class of cularine-related alkaloids (α--dimetyltetradehydrocularines). 相似文献
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A detailed hypothesis for the biogenesis of haouamines is reported herein, supported by experiments headed towards biomimetic synthesis of these compounds. 相似文献
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An experimental study was conducted in a transonic channel to control by mechanical vortex generator devices the strong interaction
between a shock wave and a separated turbulent boundary layer. Control devices—co-rotating and counter-rotating vane-type
vortex generators—were implemented upstream of the shock foot region and tested both on a steady shock wave and on a forced
shock oscillation configurations. The spanwise spacing of vortex generator devices along the channel appeared to be an important
parameter to control the flow separation region. When the distance between each device is decreased, the vortices merging
is more efficient to reduce the separation. Their placement upstream of the shock wave is determinant to ensure that vortices
have mixed momentum all spanwise long before they reach the separation line, so as to avoid separation cells. Then, vortex
generators slightly reduced the amplitude of the forced shock wave oscillation by delaying the upstream displacement of the
leading shock. 相似文献
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Bourdat-Deschamps M Herrenknecht C Akendengue B Laurens A Hocquemiller R 《Journal of chromatography. A》2004,1041(1-2):143-152
High-performance centrifugal partition chromatography (HPCPC) has been successfully applied to the separation of four protoberberine quaternary alkaloids, namely palmatine, jatrorrhizine, columbamine and pseudocolumbamine, from a methanolic extract (M1, 1.47 g) of Enantia chlorantha Oliver stem bark. For their isolation, two successive biphasic solvent systems composed of dichloromethane-methanol-water (48:16:36, v/v) were selected. The aqueous-rich phase was the stationary phase and the organic-rich phase was the mobile phase. The first system, containing potassium perchlorate, allowed to isolate 600 mg of palmatine, and to obtain 146 mg of a mixture (M2) containing only jatrorrhizine, columbamine and pseudocolumbamine. The second biphasic system, prepared with water alkalinized with sodium hydroxide, was employed to isolate the M2 components. This system applied to the purification of 70 mg of M2 allowed to obtain 16 mg ofjatrorrhizine and 13 mg of columbamine. To obtain pseudocolumbamine (16 mg), the elution mode was reversed, the aqueous-rich phase becoming the mobile phase, and the organic-rich phase becoming the stationary one. Analytical reversed-phase high-performance liquid chromatography, NMR, high-resolution mass spectrometry and UV spectrometry were used to verify the identity and the purity of the isolated compounds. 相似文献
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Six new alkaloids, periphylline 1, isoperiphylline 5, dihydroperiphylline 21, neoperiphylline 22, perimargine 23 and dihydroperimargine 24 have been isolated from the leaves of Peripterygia marginata. All these alkaloids contain a thirteen-membered ring system derived from dicinnamoylspermidine. 相似文献
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Jalce G Seck M Franck X Hocquemiller R Figadère B 《The Journal of organic chemistry》2004,69(9):3240-3241
trans-2,5-Disubstituted tetrahydrofurans were obtained as major diastereomers (trans/cis ratio 90:10-100:0) when acetylated gamma-lactols derived from (S)-glutamic acid were treated with titanium enolates of N-acetyl (R)-oxazolidin-2-thiones. A simple transesterification allowed us to obtain the corresponding methyl esters and recover the chiral auxiliary. 相似文献
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The aerial parts of Boronia ternata var. elongata from western Australia has yielded three new 2-acyl-4(1H)-quinolinone alkaloids, characterised as 2-n-pentyl-4(1H)-quinolinone, 1-methyl-2-n-pentyl-4(1H)-quinolinone and 1-methyl-2-(1 xi-methyl)-propyl-4(1H)-quinolinone, as well as known alkaloids of this class and a furoquinoline alkaloid. Boronia alulata, from northeast Queensland, also yielded 2-n-pentyl-4(1H)-quinolinone together with the known 2-n-propyl-4(1H)-quinolinone. Both species are assigned to Boronia section Valvatae which, alone among the sections of Boronia, appears to be characterised by the presence of alkaloids. 相似文献