title: Polymorphic forms of lupane triterpenoid betulonic aldehyde (betulonal).
abstract: The lupane triterpenoid betulonic aldehyde [also known as betulonal; systematic name: lup-20(29)-en-28-al-3-one, C30H46O2] is a product of betulin oxidation. Crystals were obtained from hexane [form (I)] and dimethyl sulfoxide [form (II)] solutions. Forms (I) and (II) are both orthorhombic. The molecular geometric parameters in the two forms are similar, but the structures are different with respect to the crystal packing. Polymorph (I) contains two independent molecules in the asymmetric unit, while polymorph (II) contains only one molecule, which has a disordered aldehyde group [the disorder ratio is 0.769 (4):0.231 (4)]. In each molecule, the six-membered rings have chair conformations, whereas the cyclopentane ring in each molecule adopts an envelope conformation. All the rings in the lupane nucleus are trans-fused. The extended structures of both polymorphs are stabilized by weak intermolecular C-H...O and van der Waals interactions. Weak intramolecular C-H...O interactions are also observed.
authors.affiliation: Department of Organic Chemistry, The Medical University of Silesia, Sosnowiec 41-200, Poland.
authors.forename: Elwira
authors.initials: E
authors.lastname: Chrobak
authors.affiliation: Department of Organic Chemistry, Wroclaw Medical University, Wroclaw 50-556, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Michalik
authors.affiliation: Department of Physics of Crystals, Institute of Physics, University of Silesia, Katowice 40-007, Poland.
authors.forename: Joachim
authors.initials: J
authors.lastname: Kusz
authors.affiliation: Department of Solid State Physics, Institute of Physics, University of Silesia, Katowice 40-007, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Nowak
authors.affiliation: Department of Organic Chemistry, The Medical University of Silesia, Sosnowiec 41-200, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Boryczka
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D015394:Molecular Structure; D014315:Triterpenes / Q000737:chemistry*; D000094062:Betulinic Acid; D053978:Pentacyclic Triterpenes
chemical_list: D000447:Aldehydes; D014315:Triterpenes; C000593278:betulonal; D000094062:Betulinic Acid; C480546:lupane; D053978:Pentacyclic Triterpenes
keywords: betulonal; betulonic aldehyde; biological activity; crystal structure; cytotoxic activity; hydrogen bonding; lupane triterpenoid; polymorphism