Synthesis of 2-Heteroylidene Triterpenoids: Complex Formation with Palladium and in vitro Cytotoxic Activity

The interaction of palladium(II) chloride with 2-heteroylidene of betulonic acid (prepared via the condensation with pyridine-2-carbaldehyde, pyridine-3-carbaldehyde, pyridine-4-carbaldehyde, or quinoline-2-carbaldehyde) has been studied. Two ligands and one complex have been prepared for the first time; their structures have been confirmed by 2D NMR spectroscopy and high-resolution mass spectroscopy. The E -configuration of triterpenoid 2-heteroylidenes has been confirmed for the first time. Cytotoxic activity of the compounds with respect to the А549 cell line has been assessed.