Absolute configurations of phytotoxins seiricardine A and inuloxin A obtained by chiroptical studies.

摘要: Abstract The absolute configuration (AC) of the plant phytotoxin inuloxin A, produced by Inula viscosa , and fungal seiricardine obtained from Seiridium fungi, pathogen for cypress, has been determined experimental measurements theoretical simulations chiroptical properties three related methods, namely, Optical Rotatory Dispersion (ORD), Electronic Circular Dichroism (ECD), Vibrational (VCD). Computational prediction Density Functional Theory (DFT) VCD spectra Time-dependent DFT (TDDFT) ORD ECD allowed to assign (7 R ,8 ,10 S ) AC naturally occurring (+)-inuloxin A. In case compound (−)-seiricardine which lacks useful analysis UV–Vis absorption, thus provides a hardly detectable spectrum quite low values, an introduction suitable chromophore chemical derivatization was performed. corresponding derivative, 2 -O-p -bromobenzoate ester, gave rise intense higher values. comparison computed with ones (1 ,2 ,3a ,4 ,5 ,7a (−)-2- O - p ester A then This study further supports recent trend concerted application more than single technique toward unambiguous assignment flexible complex natural products. Moreover, use derivatization, insertion chromophoric moieties treat also transparent molecules spectroscopies.