  Isolement et détermination de Structure de l' Afrocurarine; Angenot, Luc  ; et alin Planta Medica (1984), 50(2), 131-133 The structure and the stereochemistry of afrocurarine (a new unsymmetrical bisindole alkaloid) previously isolated from S. USAMBARENSIS Gilg. are established especially from (1)H-NMR spectroscopic data ... [more ▼] The structure and the stereochemistry of afrocurarine (a new unsymmetrical bisindole alkaloid) previously isolated from S. USAMBARENSIS Gilg. are established especially from (1)H-NMR spectroscopic data. The separation of quaternary alkaloids has always been very tedious. Ion-pair reversed-phase column chromatography applied to the purification of afrocurarine is proved very useful and seems to be a suitable technique in quaternary alkaloid research. [less ▲] Detailed reference viewed: 10 (4 ULg)La strychnoxanthine, un alcaloide monoterpénique d'un nouveau type isolé à partir du Strychnos gossweileri; ; et al in Planta Medica (1984), 50(1), 93-95 Strychnoxanthine, an anhydronium base, was isolated from root barks of STRYCHNOS GOSSWEILERI, a few years ago. The structure of this new indole alkaloid is now established by spectral analysis, especially ... [more ▼] Strychnoxanthine, an anhydronium base, was isolated from root barks of STRYCHNOS GOSSWEILERI, a few years ago. The structure of this new indole alkaloid is now established by spectral analysis, especially by (1)H NMR at 360 MHz. [less ▲] Detailed reference viewed: 19 (1 ULg)Isolement de Nb-méthylantirhine, malindine et isomalindine à partir du Strychnos Usambarensis; ; et al in Planta Medica (1984), 50(1), 27-30 Three quaternary alkaloids have been isolated from root barks of STRYCHNOS USAMBARENSIS Gilg from Rwanda: malindine, isomalindine and Nb-methyl-antirhine. The structure elucidation and the stereochemistry ... [more ▼] Three quaternary alkaloids have been isolated from root barks of STRYCHNOS USAMBARENSIS Gilg from Rwanda: malindine, isomalindine and Nb-methyl-antirhine. The structure elucidation and the stereochemistry of the new isomalindine has been proposed based on its spectral data and their comparison with those of malindine, its isomer. [less ▲] Detailed reference viewed: 9 (1 ULg)Les alcaloides quaternaires majoritaires du Strychnos variabilis du ZaireTits, Monique ; Franz, Michel ; et alin Planta Medica (1981), 42(8), 371-4 Two quaternary alkaloids have been isolated from the root barks of STRYCHNOS VARIABILIS collected in Zaire. The structure of these alkaloids (mavacurine and fluorocurine) could be deduced from spectral ... [more ▼] Two quaternary alkaloids have been isolated from the root barks of STRYCHNOS VARIABILIS collected in Zaire. The structure of these alkaloids (mavacurine and fluorocurine) could be deduced from spectral data: UV, MS, IR and (1)H NMR. Moreover, the stereochemistry could be assigned by (1)H NMR at 360 MHz. [less ▲] Detailed reference viewed: 36 (0 ULg)The 1H NMR spectra of the Strychnos alkaloids Retuline and Isoretuline, and their N-deacetyl compounds; ; Tits, Monique et alin Bulletin de la Société Chimique de Belgique (1978), 87(8), 595-607 The 300 MHz 1H NMR spectra of the title compounds are discussed. The vicinal coupling constants 3J H2,H16 and 3J H16,H15 are about 10Hz and 4 Hz in the iso series, and about 7 Hz and 1 Hz for retuline ... [more ▼] The 300 MHz 1H NMR spectra of the title compounds are discussed. The vicinal coupling constants 3J H2,H16 and 3J H16,H15 are about 10Hz and 4 Hz in the iso series, and about 7 Hz and 1 Hz for retuline series. In isoretuline, the piperidine ring ( ring D) has a chair conformation, but in retuline a boat conformation, with C21 in the tip position, prevails. This conclusion is based on the pattern of allylic and homoallylic couplings around the double bond, and rests also on comparison with the spectrum of strychnine. Evidence is presented for a hydrogen bond between the C17 hydroxymethyl and the N1-COCH3 group in isoretuline. [less ▲] Detailed reference viewed: 27 (1 ULg) |
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