Mannich Reaction of Solasodine with Acetylenes and Formaldehyde. Cytotoxicity of N -Propargyl-Substituted Alkaloid Derivatives

The reaction of the steroidal alkaloid solasodine with formaldehyde, terminal arylalkynes, 2-ethynylpyridine, propiolic acid methyl ester, or (trimethylsilyl)acetylene with heating to 100°C in 1,4-dioxane in the presence of CuI synthesized the corresponding N -(prop-2-ynyl)spiro solanes as mixtures of (22 R ,25 R )- and (22 S ,25 R )-diastereomers in 28–81% yields and 1.6–1:1–1.7 ratios of stereoisomers. The cytotoxicities of the new solasodine derivatives against T98G, U-87, MT-4, and MDA-MB-231 human tumor cells were tested in vitro .