title: Two crystal polymorphs of a flavonoid from Melicope ellyrana.
abstract: The crystal structure determinations of two crystalline components of the hexane extract of the fruit of the indigenous Australian tree Melicope ellyrana have shown them to be polymorphs of the same compound, namely the flavonoid 4',5-dihydroxy-3,3',8-trimethoxy-7-(3-methylbut-2-enyloxy)flavone [systematic name: 5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,8-dimethoxy-7-(3-methylbut-2-enyloxy)-4H-1-benzopyran-4-one], C(23)H(24)O(8). The two polymorphs, one monoclinic (polymorph A) and the other triclinic (polymorph B), show significant conformational differences, particularly in the enyloxy side chain, while only one (polymorph A) shows intermolecular hydrogen bonding.
authors.affiliation: Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Australia. g.smith@qut.edu.au
authors.forename: G
authors.initials: G
authors.lastname: Smith
authors.forename: J P
authors.initials: JP
authors.lastname: Bartley
authors.forename: E
authors.initials: E
authors.lastname: Wang
authors.forename: R C
authors.initials: RC
authors.lastname: Bott
mesh_terms: D018360:Crystallography, X-Ray; D005419:Flavonoids / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry; D006860:Hydrogen Bonding; D007536:Isomerism; D008958:Models, Molecular; D008968:Molecular Conformation; D027821:Rutaceae / Q000737:chemistry*
chemical_list: D005419:Flavonoids