A new dimeric pyridine, monyunine (1), together with four known compounds, were isolated from the rhizomes of Helminthostachys zeylanica. The structure of the new pyridine was elucidated by chemical and physical evidence.
A new dimeric pyridine, monyunine (1), together with four known compounds, were isolated from the rhizomes of Helminthostachys zeylanica. The structure of the new pyridine was elucidated by chemical and physical evidence.
A new pyridine, 4-(1′-acetoxy-2′-phenylethyl)-2-methylpyridine (1), along with five known compounds including (–)-xylopine (2), (–)-ushinsunine (3), (–)-norushisunine (4), (–)-formylstepharine (5), and thalifoline (6), were isolated from the flowers of Michelia champaca L. (Magnoliaceae). The structure of the new pyridine was elucidated by physical evidence.
The action of nitrating mixtures [(HNO3 + 3H2SO4), (AcOH + HNO3)] on acetylhaplophyllidine was studied. Intramolecular cyclization in two directions to form anhydroperforine (2) and spiro compound 3 or 4 and 2-nitrofuranoquinoline 5 occurred in AcOH. Loss of MeOH and H2O molecules occurred under more forcing conditions (HNO3 + 3H2SO4) and was accompanied by aromatization of ring D of anhydroperforine to produce compound 6. The structures of the obtained compounds were established using 1D and 2D NMR spectroscopy and an X-ray crystal structure analysis.
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