Paraherquamide alkaloids

This is an indole alkaloid isolated from Penicilliutn paraherquei [31]. A number of naturally occuring and semi-synthetic analogues (17b-d and 18a, b) of paraherquamide possess marked anthelminitic activity [32,33]. 

Prenyl rearrangement. Efficient total syntheses of 3-ferf-prenylated indole alkaloids employ prenyl shifts fi om C2, which can be considered biomimetic, since it was shown by Williams that the biosynthesis of paraherquamide A (199) from Penicillium sp. proceeds via tert-prenyl shift fi om C2 to C3 starting from precursors like 198 (Scheme 39) [2, 165], in agreement with earlier proposals by Barrow [166] and by Gorst-Allman [167] for the biosynthesis of roquefortine. 

Keywords Prenyiated indole alkaloids. Biosynthesis, Paraherquamides, Brevianamides, Roquefortine, Echinulin, Verruculogen, Cyclopiazonic acid. Ergot alkaloids... 

The structurally related alkaloid marcfortine, first described by Polonsky et al. in 1980 [35] is rendered from two isoprene units, tryptophan and pipecolic acid. The structures of the members of this family of mold metabolites are presented in Fig. 4. The paraherquamides differ with respect to substitution and oxygenation in the proline ring and the prenyiated oxindole ring paraherquamide B is the simplest member of the paraherquamide family, being comprised of the amino adds proline, tryptophan, and two isoprene units. 

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