Acta Cryst. (2010). E66, o81-o82 [ doi:10.1107/S1600536809051885 ]
Abstract: The title acridone alkaloid [systematic name: 1,3,5-trihydroxy-2,4-bis(3-methylbut-2-enyl)acridin-9(10H)-one], C23H25NO4, known as atalaphylline, was isolated from Atalantia monophylla Corrêa, a mangrove plant. The molecule contains three fused planar rings with an r.m.s. deviation of 0.026 (2) Å. Both 3-methylbut-2-enyl substituents are in a (-)anticlinal conformation. An intramolecular N-HO hydrogen bond generates an S(5) ring motif, while an intramolecular O-HO hydrogen bond generates an S(6) ring motif. In the crystal structure, the molecules are linked into screw chains along  by intermolecular O-HO hydrogen bonds. These chains are stacked along the a axis by - interactions with centroid-centroid distances of 3.6695 (13) and 3.6696 (13) Å.
Online 9 December 2009
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