Total Syntheses of Ningalin A, Lamellarin O, Lukianol A, and Permethyl Storniamide A Utilizing Heterocyclic Azadiene Diels−Alder Reactions

Dale L. Boger, Christopher W. Boyce, Marc Labroli, Clark A. Sehon, Qing Jin

Journal of the American Chemical Society · 1998 · 384 citations · 21 references

Concepts

Abstract

Concise, efficient total syntheses of ningalin A ( 1 ), lamellarin O ( 2 ), lukianol A ( 3 ), and permethyl storniamide A ( 5 ) are detailed on the basis of a common heterocyclic azadiene Diels−Alder strategy (1,2,4,5-tetrazine → 1,2-diazine → pyrrole) ideally suited for construction of the densely functionalized pyrrole cores found in the three classes of marine natural products. Examination of the natural products and a number of synthetic intermediates revealed that some including lamellarin O ( 2 ) and lukianol A ( 3 ) exhibit modest cytotoxic activity against both wild-type and multidrug-resistant tumor cell lines. Fundamentally more important, a new class of agents including permethyl storniamide A ( 5 ) and its precursor 30, which lack inherent cytotoxic activity, are disclosed which reverse the multidrug-resistant (MDR) phenotype, resensitizing a human colon cancer cell line (HCT116/VM46) to vinblastine and doxorubicin at lower doses than the prototypical agent verapamil.

References

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