title: Six new diterpenoids from Suregada multiflora.
abstract: Six new diterpenoids were isolated from a CH(2)Cl(2)-MeOH extract of the bark of Suregada multiflora. The structures were established on the basis of one- and two-dimensional NMR and other spectroscopic studies and chemical derivatizations. Two compounds, suregadolides C (1) and D (2), were identified as new diterpene lactones of two antipodal series, containing a cyclopropane ring bridging C-3 and C-4 of the basic abietane skeleton. Suremulide A (3) was found to be a new abietene diterpene lactone. Bannaringaolide A (4), a diterpene lactone, based on a novel carbon skeleton with a seven-membered ring, possibly formed by the rearrangement of the exocyclic C-17 in ring C of an ent-pimarane framework, has also been isolated. A kaurane triol, suremulol A (5), and a kaurane diol, suremulol B (6), were also identified as new metabolites.
authors.affiliation: Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh.
authors.forename: Ismet Ara
authors.initials: IA
authors.lastname: Jahan
authors.forename: Nilufar
authors.initials: N
authors.lastname: Nahar
authors.forename: M
authors.initials: M
authors.lastname: Mosihuzzaman
authors.forename: Farzana
authors.initials: F
authors.lastname: Shaheen
authors.lastname: Atta-Ur-Rahman
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D045784:Abietanes / Q000737:chemistry / Q000302:isolation & purification*; D001459:Bangladesh; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D024301:Plant Bark / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D029843:Suregada / Q000737:chemistry*
chemical_list: D045784:Abietanes; D004224:Diterpenes; D007783:Lactones; C494226:suregadolide C; C494924:suregadolide D