Transformation of Grayanotoxin-II/Grayanotoxin-II Tetraacetate to 1, 5-seco Grayano-toxin Derivatives

Abstract

Oxidation of grayanotoxin (GTX) II with lead (IV) acetate in methanol gave a new derivative, the 1(R)-spiro-3, 6(S), 14, 16-tetra-hydroxy-5-keto derivative. Treatment of GTX-II tetraacetate in acetic acid by using Pb(IV) acetate as an oxidizing agent gave a novel 1, 5-seco-GTX derivative, Δ¹⁽¹⁰⁾-1, 5-seco-GTX-pentaacetate, together with the l, 5-seco-GTX-1(R) derivative. Oxidation of GTX-II-tetraacetate with Tl(III) acetate in acetic acid or benzene gave the 1, 5-seco-GTX-1 (S) derivative.