Myrothecium verrucaria grown on a large scale (760 L) has yielded a variety of new trichothecenes including the nonmacrocyclic trichoverroids 13-19, which contain a pendant C4 cis,trans-dienic ester side chain normally common only to the macrocyclic roridins and verrucarins. Several novel macrocyclic trichothecenes (roridins J and K acetate) and verrucarins L and L acetate also were isolated and characterized.The trichothecene complex of antibiotics has generated due to the wide spectrum of biological activity exhibited a great deal of interest during the past 10 years, principally by these sesquiterpene mycotoxins.

Verrucarin A (2) was epoxidized to give the beta-9,10-epoxide 7 (major product) and alpha-9,10-epoxide 9 (minor product). The beta-epoxide 7 and its acetate 8 exhibit high in vivo antileukemic activity against P-388 mouse leukemia, whereas 2 and 9 are inactive. Epoxidation of verrucarin B (3) and roridin A (1) to their respective beta-9,10-epoxides (11 and 12, respectively) also yields compounds with substantially increased activity. Allylic alcohols derived from 2, alpha-C8 (20), beta-C8 (14), and C16 (15), were synthesized and tested; only 15 exhibited substantial in vivo activity.

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