Synthesis of Optically Pure Clausenamine-A and its Demethoxylated Analogs
作者:Guoqiang Lin、Aimin Zhang
DOI:10.1016/s0040-4020(00)00634-7
日期:2000.9
total synthesis of Clausenamine-A (3) was developed involving the Suzuki cross-coupling and oxidativecoupling reaction. The synthesis of its demethoxylated analogs 1 and 2 were also reported. Resolution of (+)-1, (+)-2, (+)-3 and (−)-1, (−)-2, (−)-3 were performed via their corresponding camphorsulfonates of the racemates. The absolute configurations of (+)-1, (+)-2, (+)-3 and (−)-1, (−)-2, (−)-3 were
Antiplasmodial Activity of Mono- and Dimeric Carbazoles
作者:Gerhard Bringmann、Alfons Ledermann、Jörg Holenz、Muh-Tsuen Kao、Ulrich Busse、Howard Wu、Guido François
DOI:10.1055/s-2006-957366
日期:1998.2
A series of mono-and dimeric natural and structurally modified carbazoles has been tested for activity against Plasmodium falciparum. One of the monomers, the synthetic compound 1,4-diacetoxy-3-methylcarbazole (17), displays the highest activity, with an IC50 value of 1.79 µg/ml. It is distinctly more active than the as yet best natural compound, 1-hydroxy-3-methylcarbazole (4) (4).
Oxidative aryl coupling reactions: a biomimetic approach to configurationally unstable or axially chiral biaryl natural products and related bioactive compounds
作者:Gerhard Bringmann、Stefan Tasler
DOI:10.1016/s0040-4020(00)00940-6
日期:2001.1
products and related compounds in the fields of biphenyls, biscarbazoles and bisnaphthylisoquinolines. For sterically more hindered biaryls, which consequently show the phenomenon of axialchirality, the products were prepared in an atropisomerically pure form. Their absoluteaxialconfigurations were assigned mainly by experimental and computational CD investigations.
The first total synthesis of a naturally occurring dimeric carbazole alkaloid, bismurrayaquinone A (4), is described, by oxidation of dimeric O-demethylmurrayafoline A, a still hypothetic natural product recently synthesized. By chromatography on a chiral phase, the two atropoenantiomers were separated. The absolute configurations of these two rotational isomers were elucidated by comparison of their calculated spectra with those measured experimentally.
Dimeric Murrayafoline A, a potential Bis-Carbazole Alkaloid: 'Biomimetic' Synthesis, Atropoisomer Separation, and Antimalarial Activity
作者:Gerhard Bringmann、Alfons Ledermann、Guido François
DOI:10.3987/com-94-s30
日期:——
The first total synthesis of a (potential) dimeric carbazole alkaloid is described. After an improved preparation of the monomeric building block, ''biomimetic dimerization'' by oxidative phenolic coupling was best achieved with di-terf-butyl peroxide in chlorobenzene, leading to a highly selective formation of the 2,2'-coupled ''dimer'', the parent framework of several naturally occurring dimeric carbazole alkaloids. For the atropo-enantiomer analysis, a chromatographic procedure on a chiral phase was developed. Both the mono- and the dimeric phenolic carbazoles displayed in vitro antimalarial activity against Plasmodium falciparum.