Synthesis of Indole Phytoalexins Brassinin and Cyclobrassinin via [1-(tert-Butoxycarbonyl)indol-3-yl]-methyl Isothiocyanate as the Key Biomimetic Intermediate
Synthesis of Indole Phytoalexins Brassinin and Cyclobrassinin <i>via</i> [1-(<i>tert</i>-Butoxycarbonyl)indol-3-yl]-methyl Isothiocyanate as the Key Biomimetic Intermediate
A four-step synthesis of 1-protected indol-3-ylmethyl isothiocyanates from indole-3-carboxaldehyde has been elaborated. [1-(tert-Butoxycarbonyl)indol-3-yl]-methyl isothiocyanate appeared to be a suitable biomimetic intermediate for the synthesis of protected phytoalexins brassinin and cyclobrassinin. Removing of the tert-butoxycarbonyl protecting group under specific conditions afforded phytoalexins identical with previously described compounds.
brassinin, brassitin, cyclobrassinin and related compounds via 3-aminomethylindole and its 1-substituted derivatives obtained by nickelboride catalyzed reduction of corresponding aldoximes with sodium borohydride and via[1-(t-butoxycarbonyl)-indol-3-yl]methyl isothiocyanate, the first stable derivative of indol-3-ylmethyl isothiocyanate is described. Antifungal activity of the prepared compounds was examined