Convergent Synthesis of Solamargine and Analogues Thereof: Structural Revision of 16-epi-Solamargine and Cytotoxic Evaluation

摘要

An effective and stereoselective protocol for convergent synthesis of solamargine, a representative of spirosolane-type glycoalkaloids, is reported. HB(C6F5)(4)-catalyzed coupling of 26-azido-pseudodiosgenin with chacotriosyl trichloroacetimidate as the key step for synthesis of solamargine proceeded in high yield and with excellent stereoselectivity. Three analogues of solamargine were synthesized by the method. Protonation of the nitrogen atom by deuterium chloride had a significant influence on the (HNMR)-H-1 spectrum of solamargine. On the basis of these results, the structure of 16-epi-solamargine was revised to solamargine hydrochloride. The cytotoxicity of solamargine together with its analogues against cancer cell lines was evaluated.