title: Candibirin A, a furanocoumarin dimer isolated from Heracleum candicans WALL.
abstract: Candibirin A [systematic name: 9,9'-(1,4-dioxane-2,5-diyldimethylenedioxy)di(7H-furo[3,2-g]chromen-7-one)], a new furanocoumarin dimer, was isolated from Heracleum candicans WALL. (1)H NMR and MS spectra had indicated that the title compound was a dimer of heraclenin or heraclenol, but the linkage structure and its chirality were undetermined. The dioxane linkage, having the R,R configuration, has now been elucidated from dimethyl sulfoxide-solvated crystals, C(32)H(28)O(10).2C(2)H(6)OS. Candibirin A is thus a dimerization product from heraclenin formed by reaction at the epoxy group. Dimethylformamide-solvated crystals, C(32)H(28)O(10).C(3)H(7)NO, adopt a different conformation, with a folded structure that differs from the extended structure in the dimethyl sulfoxide solvate. However, the puckering of the dioxane linker unit is very similar in the two conformers. This result shows that the rotation of the ether bonds, in the linker between the furanocoumarin and dioxane moieties, causes the conformational flexibility of (I).
authors.affiliation: Osaka University of Pharmaceutical Sciences, Nasahara, Takatsuki, Osaka 569-1094, Japan. doit@gly.oups.ac.jp
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Doi
authors.forename: Terue
authors.initials: T
authors.lastname: Nakamori
authors.forename: Makio
authors.initials: M
authors.lastname: Shibano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Nian He
authors.initials: NH
authors.lastname: Wang
authors.forename: Kimiye
authors.initials: K
authors.lastname: Baba
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004121:Dimethyl Sulfoxide; D030002:Heracleum / Q000737:chemistry*; D029001:Herbal Medicine; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D012997:Solvents
chemical_list: D018712:Analgesics, Non-Narcotic; D012997:Solvents; D004121:Dimethyl Sulfoxide