Phytotoxic compounds produced by Fusarium equiseti. Part 9. Reactions of some 9β,10β; 12,13-diepoxytrichothecanes

Abstract

The 9β,10β-epoxides of a number of naturally-occurring non-macrocyclic 12,13-epoxytrichothec-9-enes have been prepared, and the possible formation of 10β,13-epoxytrichothecanes when these diepoxides are treated with nucleophilic reagents has been investigated. In the presence of a 15-oxygen substituent, as in diacetoxyscirpenol 9β,10β-epoxide, intramolecular attack with formation of a 9α,15-epoxide takes precedence over the intermolecular addition of a nucleophile. With the 8α-hydroxy compound trichothecodiol 9β,10β-epoxide, intramolecular attack also occurred giving an 8α,9α; 10β,13-diepoxytrichothecane together with known derivatives of trichothecolone. With trichodermol epoxide, the two epoxide groupings reacted independently. The significance of these results to the mechanism of action of the 12,13-epoxytrichothec-9-ene mycotoxins is discussed. An unexpected autoxidation is reported.