title: Absolute configurations of three ent-beyerene derivatives.
abstract: (1): 11 beta,17-Bis(4-bromobenzoyloxy)-9 beta-hydroxy-ent-beyerene, C34H38Br2O5, Mr = 686.5, orthorhombic, P2(1)2(1)2(1), a = 6.1686 (12), b = 14.613 (3), c = 32.935 (7) A, V = 2969 (1) A3, Z = 4, Dx = 1.536 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 27.43 cm-1, F(000) = 1408, T = 173 K, R = 0.0347 and wR = 0.0358 for 3064 reflections [Io greater than or equal to 3 sigma(Io)]. (2): 7 beta,17-Bis(4-bromobenzoyloxy)-9 beta-hydroxy-ent-beyerene, C34H38Br2O5, Mr = 686.5, monoclinic, P2(1), a = 12.6424 (15), b = 6.8353 (12), c = 18.496 (2) A, beta = 101.901 (9) degrees, V = 1564.0 (4) A3, Z = 2, D chi = 1.458 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 26.03 cm-1, F(000) = 704, T = 173 A, R = 0.0336 and wR = 0.0361 for 4610 reflections [Io greater than or equal to 3 sigma(Io)]. (3): 17-(4-Bromobenzoyloxy)-9 beta,11 beta-epoxy-7 beta-hydroxy-ent-beyerene, C27H33BrO4, Mr = 501.5, orthorhombic, P2(1)2(1)2(1), a = 6.1315 (7), b = 18.389 (3), c = 21.109 (3) A, V = 2380.0 (6) A3, Z = 4, D chi = 1.399 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 17.38 cm-1, F(000) = 1048, T = 198 K, R = 0.0325 and wR = 0.0344 for 2292 reflections [Io greater than or equal to 3 sigma(Io)].(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Chemistry, University of Texas, Austin 78712.
authors.forename: K A
authors.initials: KA
authors.lastname: Abboud
authors.forename: S H
authors.initials: SH
authors.lastname: Simonsen
authors.forename: E F
authors.initials: EF
authors.lastname: Lee
authors.forename: T J
authors.initials: TJ
authors.lastname: Mabry
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D003460:Crystallization; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification; D006368:Helianthus / Q000032:analysis*; D008968:Molecular Conformation; D015394:Molecular Structure; D014961:X-Ray Diffraction
chemical_list: D004224:Diterpenes; C070214:7,17-bis(4-bromobenzoyloxy)-9-hydroxybeyerene; C070213:11,17-bis(4-bromobenzoyloxy)-9-hydroxybeyerene; C070215:17-(4-bromobenzoyloxy)-9,11-epoxy-7-hydroxybeyerene