Monde Kenji, Taniguchi Tohru, Miura Nobuaki, Kutschy Peter, Curillová Zuzana, Pilátová Martina, Mojzis Ján
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.
Bioorg Med Chem. 2005 Sep 1;13(17):5206-12. doi: 10.1016/j.bmc.2005.06.001.
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.
