Chiral cruciferous phytoalexins: preparation, absolute configuration, and biological activity.
Synthesized by an efficient one-pot spirocyclization method, two chiral cruciferous phytoalexins, 1-methoxyspirobrassinin (2) and 1-methoxyspirobrassinol methyl ether (4a), were prepared through optical resolution using the chiral HPLC method of corresponding racemates. The absolute configuration of natural (+)-2 was elucidated as R by using the direct comparison of ECD and VCD spectra with those of known (S)-(-)-spirobrassinin (1). Another chiral phytoalexin, (-)-4a, had its absolute configuration 2R,3R elucidated through the comparison of observed and calculated VCD. Interestingly, the absolute configurations of natural (S)-(-)-spirobrassinin (1) and (R)-(+)-1-methoxyspirobrassinin (2) were opposite of each other, even though their structures are almost similar, with the exception of an N-methoxy group. A significant difference in the antiproliferative activity between (2R,3R)-(-) and (2S,3S)-(+)-4a was observed.
Division of Biological Sciences, Graduate School of Science, Frontier Research Center for Post-Genomic Science and Technology, Hokkaido University, Kita-ku, Sapporo 001-0021, Japan. kmonde@glyco.sci.hokudai.ac.jp
Kenji
K
Monde
Tohru
T
Taniguchi
Nobuaki
N
Miura
Peter
P
Kutschy
Zuzana
Z
Curillová
Martina
M
Pilátová
Ján
J
Mojzis
D019607:Brassicaceae / Q000737:chemistry*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D055095:Optics and Photonics; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D012717:Sesquiterpenes; D013237:Stereoisomerism; D013729:Terpenes; D000094162:Phytoalexins
D010936:Plant Extracts; D012717:Sesquiterpenes; D013729:Terpenes; D000094162:Phytoalexins