1H and 13C resonance designation of antimycin A1 by two-dimensional NMR spectroscopy

Complete ¹H and ¹³C resonance assignments of antimycin A₁ were accomplished by two-dimensional NMR techniques, viz. ¹H homonuclear COSY correlation, heteronuclear ¹³C-¹H chemical shift correlation and long-range heteronuclear ¹³C-¹H COLOC correlation. Antimycin A₁ was found to consist of two isomeric components in a 2:1 ratio based on NMR spectroscopic evidence. The structure of the major component was newly assigned as the 8-isopentanoic acid ester. The spectra of the minor component were consistent with the known structure of antimycin A₁.