title: Five diterpenoids (agallochins A-E) from the mangrove plant Excoecaria agallocha Linn.
abstract: Chemical examination of the hexane extract of the roots of Excoecaria agallocha Linn collected from the Godavari estuary resulted in the isolation of altogether eleven diterpenoids of which five (1-5) are new. The structures of the new diterpenoids have been elucidated by a study of their physical and spectral (UV, IR, 1H, 13C, DEPT, 1H-1H COSY, NOESY, HMQC, HMBC and MASS) data as 3-oxo-ent-13epi-8(13)-epoxy-15-chloro-14-hydroxylabdane (1), ent-15-chloro-13,14-dihydroxylabd-8(9)-en-3-one (2), ent-15-chloro-labd-8(9)ene-3alpha,13,14-triol (3), ent-11beta-hydroxy-8(14),15-isopimaradien-3-one (4), 8,13-epoxy-3-nor-2,3-seco-14-epilabden-2,4-olide (5). The six known diterpenoids have been characterised respectively as ent-3-oxo-13-epi-manoyl oxide (6), ent-3beta-hydroxy-13-epi-manoyl oxide (7), (13R,14S)-ent-8alpha,13;14,15-diepoxy-13-epi-labdan-3-one (8), ent-16-hydroxy-3-oxo-13-epimanoyl oxide (9), ent-15-hydroxylabda-8(17),13E-dien-3-one (10), labda-8(17),13E-diene-3beta,15-diol (11) by a comparative study of their spectral data with the literature values.
authors.affiliation: School of Chemistry, Andhra University, Visakhapatnam, India. orgchem@satyasaionline.net.in
authors.forename: A S
authors.initials: AS
authors.lastname: Anjaneyulu
authors.forename: V L
authors.initials: VL
authors.lastname: Rao
mesh_terms: D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D019665:Euphorbiaceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation
chemical_list: D004224:Diterpenes