6835-99-0Relevant academic research and scientific papers
Preparation methods for chiral impurities of vincamine
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, (2019/03/10)
The invention relates to preparation methods for chiral impurities of vincamine. Through oriented synthesis method and the later column chromatography separation, high purity product of seven chiral impurities can be obtained, and the preparation methods can be used for the qualitative and quantitative analysis of impurities in the production of vincamine, so that the separation and confirmation of the seven chiral impurities in vincamine drugs can be realized, and the drug standard of the vincamine can be enhanced, and therefore, the vincamine with high purity can be obtained. Compared with existing preparation methods for the vincamine, the preparation methods relate to the preparation of seven chiral isomers, and are more complete and simpler in operation.
Synthesis of 18-hydroxyvincamines and epoxy-1,14-secovincamines; A new proof for the aspidospermane-eburnane rearrangement
Nemes, Andras,Szantay Jr., Csaba,Czibula, Laszlo,Greiner, Istvan
, p. 2347 - 2362 (2008/09/18)
Chemical transformations started from tabersonine were studied. A one-pot oxidative ring-transformation with permaleic acid in methanol yielded 17,18-dehydrovincamine. Hydroboration-oxidation of the latter compound led to alkaloid 17,18-dehydrovincamone. Hydroboration-oxidation of tabersonine resulted 14β-hydroxyvincadifformine and 15β-hydroxyvincadifformine. Allowing 14β- and 15β- hydroxyvincadifformines to react with permaleic acid/methanol provided 1,14-secovincamines, serving as new evidence for the mechanism of the aspidospermane-eburnane transformation. On the other hand 18β-hydroxyvincamine was obtained from 14β-hydroxyvincadifformine by reaction with 3-chloroperbenzoic acid and successive treatment with triphenylphosphine/aqueous acetic acid.
Syntheses and Cardiovascular Activity of Stereoisomers and Derivatives of Eburnane Alkaloids
Czibula, Laszlo,Nemes, Andras,Visky, Gyoergy,Farkas, Maria,Szombathelyi, Zsolt,et al.
, p. 221 - 230 (2007/10/02)
The synthesis of all the possible isomers of the eburnamenine-vincamine type alkaloids 1b, 2a*, 3a and derivatives 4, 8, 9, 10 is described.Structures were determined by 1H- and 13C-NMR spectroscopy including special techniques such as DR, DEPT, DNOE, and 2D-HSC.In contrast to the known cerebrovascular effects of cis-(3S,16S) compounds, trans-(3S,16R) derivatives show a significant peripheral vasodilator effect. Key Word: Eburnanes / Alkaloids / Cardiovascular effects / Indoloquinolizines
ALTERNATIVE ROUTES TO VINCAMINE
Nemes, Andras,Czibula, Laszlo,Visky, Gyorgy,Farkas, Maria,Kreidl, Janos
, p. 2329 - 2338 (2007/10/02)
The preparation of vincamine (1a) via indoloquinolizine propionic esters (7) is discussed.A new synthesis of the starting material methyl 2-acetoxyacrylate and an oxidative transformation of 7b to 1a are described and an alternative, more efficient route is reported.
SYNTHESIS OF VINCA ALKALOIDS AND RELATED COMPOUNDS, XLIX. AROMATIC SUBSTITUENT EFFECTS IN THE C-14 EPIMERIZATION
Moldvai, Istvan,Vedres, Andras,Szantay, Csaba,Toth, Gabor,Szantay, Csaba
, p. 109 - 118 (2007/10/02)
Some A-ring substituted vincamine derivatives and their C-14 epimers have been prepared and the aromatic substituent effects on the epimeric equilibrium of these compounds investigated.
Nouvelles hemisyntheses de la (+)vincamine et de la (-)vincamone
Lewin, Guy,Poisson, Jacques
, p. 435 - 437 (2007/10/02)
A new course in the hemisynthesis of (+)vincamine 2a and (-)vincamone 3 indole alkaloids of medicinal interest from (-)apovincamine 1a is described.Apovincamine itself was obtained from vincadifformine 4 by an original process recently related (N-chlorosuccinimide in pure CF3COOH or HCOOH).The conversion of apovincamine into vincamine involves three steps, with or without isolation of the intermediate compounds: a) addition of bromine in methanol to the double bond (C-16)-(C-17) b) catalytic hydrogenolysis of the (C-17)-Br bond in vincamine O-methyl ether 9 c) hydrolysis of 9 resulting in a mixture of vincamine 2a and 16-epivincamine 2b.The conversion of apovincamine into vincamone is carried out after saponification to apovincaminic acid 1b.Addition of bromine in aqueous medium, and further acidification and heating yields vincamone by a single step process.
THERMAL REARRANGEMETS OF SOME INDOLE ALKALOID DERIVATIVES
Hugel, Georgette,Levy, Jean
, p. 1067 - 1074 (2007/10/02)
Under both static and flow thermolysis conditions, several compounds with an "aspidosperma" framework rearranged to "vinca" derivatives.Thus (-)1,2-dehydroaspidospermidine (4) rearranged to (-)aspidospermidine and compound 17 on pyrolysis (200 deg C) while flow termolysis (580 deg C) gave vincane (14).Compound 6 rearranged to vincamine (13a) and 16-epivincamine (13b) under either condition; increasing the temperature resulted in formation of apovincamine (19) (pyrolysis) or vincamone (16) (flow thermolysis).
Dye-sensitized Photo-oxygenation of the Aspidosperma Alkaloids Vincadifformine and Tabersonine. A New, Convenient Approach to Vincamine
Calabi, Luisella,Danieli, Bruno,Lesma, Giordano,Palmisano, Giovanni
, p. 1371 - 1380 (2007/10/02)
The dye-sensitized photo-oxygenation of (-)-vincadifformine (1) and (-)-tabersonine (3) is discribed.Reaction takes place through the intermediate formation of 16-hydroperoxyindolenines, which decompose to give 2,16-seco-products or which can be efficently trapped by reductants to give a new stereoselective synthesis of the 16-hydroxy-indoles (10) and (14).These compounds are the key precursors to the eburnane alcaloids vincamine (4) and Δ14-vincamine (6).Suitable experimental conditions give compounds (4) and (6) in good yields directly from their Aspidosperma precursor.
