Transformation of Grayanotoxin III to the 1, 5-seco-Grayanotoxin Derivative, Grayanol B

Abstract

Treatment of grayanotoxin (G) III with pyruvic acid in methanol gave the Δ1(10)-1,5-seco-G derivative. Photo-sensitized oxygenation of Δ1 (10)-1 ,5-seco-G under UV light irradiation in methanol gave the 1(S)-perhydroxy- and 1(S)-hydroxy-1,5-seco-G derivatives. The IR and NMR data for Δ1(10)-1(S)-hydroxy-1,5-seco-G were identical with those of natural grayanol B described in the literature.