LAUSR

Abstract Seven new alkaloids belonging to three typical classes, isolated from an ethanolic extract of Pandanus amaryllifolius , were applied to establish the models in structural elucidation. The first type [pandanusines A and B ( 1 and 2 )] was applied to alkaloids with a diazaspirocyclic ring system. The absolute stereochemistry of aminal carbon is determined by analysis of J -based configuration analysis and circular dichroism spectroscopy, which has never been revealed before. The second type [pandalizines C–E ( 3 – 5 )], the stereochemistry of unusual indolizinone with chiral hydroxyl substitutions were determined by circular dichroism spectroscopy and vibrational circular dichroism experiments. The last type [norpandamarilactonines C and D ( 6 and 7 )], a comparing model in determination of diastereomers of pyrrolidinyl α , β -unsaturated γ -lactone alkaloids was established. Our study provides solutions for a challenging subject in stereochemistry determination for three different types of Pandanus alkaloids.