title: Quesnoin, a novel pentacyclic ent-diterpene from 55 million years Old Oise Amber.
abstract: Amber, fossilized tree resin, found at the Oise River area of the Paris basin (France) was dated as being 55 million years old. Quesnoin, a novel unique pure organic compound, was isolated from Oise amber. 1H and 13C NMR spectroscopic analysis indicated an unknown diterpene skeleton, quesnane. The absolute configurations of the eight chiral centers of quesnoin were determined to be 4S, 5S, 8R, 9S, 10S, 13S, 14R, and 16S by chiral auxiliary (R)- and (S)-phenylglycine methyl ester derivatization. Quesnoin allowed us to disclose the tree producer, corresponding to modern Hymenaea oblongifolia, Fabaceae, a subfamily of Caesalpiniaceae, one of the oldest angiosperm. The presence of the Amazon rainforest tree, H. oblongifolia, indicated that the climate of the Paris basin might have been tropical in the early Eocene period, 55 million years ago.
authors.affiliation: Laboratoire de Chimie des Substances Naturelles, CNRS UMR5154, Muséum National d'Histoire Naturelle, 63 rue Buffon 75005 Paris, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Jossang
authors.forename: Hakima
authors.initials: H
authors.lastname: Bel-Kassaoui
authors.forename: Akino
authors.initials: A
authors.lastname: Jossang
authors.forename: Mannan
authors.initials: M
authors.lastname: Seuleiman
authors.forename: André
authors.initials: A
authors.lastname: Nel
mesh_terms: D018647:Amber / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification; D005580:Fossils; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008958:Models, Molecular; D008968:Molecular Conformation; D012015:Reference Standards
chemical_list: D018647:Amber; D004224:Diterpenes; C527422:quesnoin