Ningalin b analogs employable for reversing multidrug resistance

摘要

Anlogs of ningalin B lacking inherent cytotoxic activity may be employed to reverse multi-drug resistant (MDR) phenotype and to resensitize transformed cells, including a human colon cancer cell line (HCT116/VM46), with respect to a variety of cytotoxic agents, e.g., vinblastine and doxorubicin. In many instances, resensitization is achieved at lower doses than the prototypical agent verapamil. Total synthesis of ningalin B and its analogs was achieved using a concise, efficient approach based on a heterocyclic azadiene Diels-Alder strategy (1,2,4,5-tetrazine 1,2-diazine pyrrole) ideally suited for construction of the densely functionalized pyrrole core found in the natural product is detailed.