NMR studies on natural and synthetic Amavadin

The stereochemistry of isolated natural product Amavadin, which contains a 1:2 complex of V(IV) with N-hydroxyimino-2,2′-dipropionic acid (HIDPAH3), and some synthetic complexes have been investigated. Amavadin was isolated from Amanita muscaria and oxidized with [NH4]2[Ce(NO3)6]. H2[Δ-V(S,S-HIDPA)2].3H2O, H2[Δ,Λ-V(S,S-HIDPA)2].3H2O and their equivalent oxidized species have been synthesized and characterized spectroscopically. A combination of COSY, NOE, 1H, 13C-NMR and CD spectroscopy have been used to prove that the isolated natural product Amavadin consists of an almost equal mixture of the Δ- and Λ-isomers of [V(S,S-HIDPA)2]2−.