Baccharis megapotamica roridins from

The roridin family constitutes another subclass of the trichothecane macrolides. Two examples of this group are roridin E (148) and baccharin Bj (150). The latter is isolated from the plant Baccharis megapotamica and is a potent antileukemic agent. Structurally, this class of compounds is quite similar to the verrucarins discussed above, with the exception of the replacement of the hydroxypentanoic acid-muconic ester linkage by an ether bond and some additional carbon substitution. 

In 1983, Still et al. published methods for the total synthesis of roridin E (378) and baccharin B5 (379) (332). Roridin E (378) was isolated for the first time in 1965 from Myrothecium verrucaria and baccharin B5 (379) was obtained in 1976 from the plant Baccharis megapotamica (333,334). 

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