C5′-Alkyl Substitution Effects on Digitoxigenin α-l-Glycoside Cancer Cytotoxicity
摘要:
A highly regio- and stereoselective asymmetric synthesis of various CS'-alkyl side chains of rhamnosyl- and amicetosyl-digitoxigenin analogues has been established via palladium-catalyzed glycosylation with postglycosylated dihydroxylation or diimide reduction. The C5'-methyl group in both alpha-L-rhamnose and cc-L-amicetose digitoxin analogues displayed a steric directed apoptosis induction and tumor growth inhibition against nonsmall cell human lung cancer cells (NCI-H460). The antitumor activity is significantly reduced when the steric hindrance is increased at the C5'-stereocenter.