A Convergent Total Synthesis of 19-Hydroxysarmentogenin

摘要

Crossopetalum gaumeri (Loes.), a medical plant among the Yucatec Mayan community, contains various highly cytotoxic natural products, including 19-hydroxysarmentogenin-3β-O-β-6-deoxyguloside (Figure 1). This compound belongs to a family of cardenolides and bufadienolides, which are typified by ouabain and bryophilin C. Cardenolides and bufadienolides have been used for hundreds of years in both Western and Eastern medicine, and share the capacity to slow the heart rate and to increase the force of contraction of heart muscle tissue. The positive inotropic activity is attributed to a high affinity inhibitory interaction with the extracellular surface of the membrane-bound sodium pump (Na~+/K~+-ATPase) responsible for Na~+/K~+ exchange. In addition to their cardiac activity, these molecules exhibit strong cytotoxic activity against various cultured human cancer cells. Accordingly, their potential use in oncology has been investigated. Furthermore, cardenolides and bufadienolides have been identified in mammalian tissues and plasma, and thus these compounds are also considered as endogenous factors to regulate physiological phenomena.