title: Determination of the absolute configuration of perylene quinone-derived mycotoxins by measurement and calculation of electronic circular dichroism spectra and specific rotations.
abstract: Altertoxins I-III, alterlosins I and II, alteichin (alterperylenol), stemphyltoxins I-IV, stemphyperylenol, stemphytriol, 7-epi-8-hydroxyaltertoxin I, and 6-epi-stemphytriol are mycotoxins derived from perylene quinone, for which the absolute configuration was not known. Electronic circular dichroism (ECD) spectra were calculated for these compounds and compared with measured spectra of altertoxins I-III, alteichin, and stemphyltoxin III and with reported Cotton effects. Specific rotations were calculated and compared with reported specific rotations. The absolute configuration of all the toxins, except for stemphyltoxin IV, could thus be determined. The validity of the assignment was high whenever reported ECD data were available for comparison, and the validity was lower when the assignment was based only on the comparison of calculated and reported specific rotations. ECD spectra are intrinsically different for toxins with a biphenyl substructure and for toxins derived from dihydroanthracene.
authors: Institute for Organic Chemistry, Karlsruhe Institute for Technology (KIT), Campus South, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-47652. joachim.podlech@kit.edu.
authors: Joachim
authors: J
authors: Podlech
authors: Stefanie C
authors: SC
authors: Fleck
authors: Manfred
authors: M
authors: Metzler
authors: Jochen
authors: J
authors: Bürck
authors: Anne S
authors: AS
authors: Ulrich
mesh_terms: D000528:Alternaria / Q000737:chemistry*; D002942:Circular Dichroism; D008958:Models, Molecular; D008968:Molecular Conformation; D009183:Mycotoxins / Q000737:chemistry* / Q000302:isolation & purification; D010569:Perylene / Q000031:analogs & derivatives* / Q000302:isolation & purification; D011789:Quantum Theory; D011809:Quinones / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D009183:Mycotoxins; D011809:Quinones; D010569:Perylene
keywords: DFT calculations; absolute configuration; circular dichroism; mycotoxins; quinones