Isolation and absolute configuration determination of alkaloids from Pandanus amaryllifolius

• Published in: Tetrahedron Vol. 73; no. 25; pp. 3423 - 3429
• Main Authors: Cheng, Yuan-Bin, Hu, Hao-Chun, Tsai, Yu-Chi, Chen, Shu-Li, El-Shazly, Mohamed, Nonato, Maribel G., Wu, Yang-Chang, Chang, Fang-Rong
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 22.06.2017; Elsevier
• Subjects: Absolute configuration; Alkaloids; carbon; chemical reactions; Chemistry; Chemistry, Organic; circular dichroism spectroscopy; diastereomers; Pandanus amaryllifolius; Physical Sciences; Science & Technology; stereochemistry; Pandanus amaryllifolius; Alkaloids; Absolute configuration; ROOTS; PANDAMARILACTONINE-A; EXTRACTS; LEAF; PYRROLIDINE ALKALOIDS
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2017.05.002

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. Seven new alkaloids, pandanusines A and B (1 and 2), pandalizines C–E (3–5), and norpandamarilactonines C and D (6 and 7) were isolated from Pandanus amaryllifolius. The stereochemistry determination for three different types of Pandanus alkaloids was established. [Display omitted]