title: The absolute configuration of 1-(3',4'-dihydroxycinnamoyl)cyclopentane-2,3-diol from the amazonian tree Chimarrhis turbinata.
abstract: An antioxidant, 1-(3',4'-dihydroxycinnamoyl)cyclopentane-2,3-diol [or (E)-2,3-dihydroxycyclopentyl-3-(3',4'-dihydroxyphenyl)acrylate (1)], and two known trans- and cis-chlorogenic acid methyl esters were isolated from the ethanolic extract of the leaves of Chimarrhis turbinata. The relative configuration of 1 was determined by NMR and by comparison of the circular dichroic spectrum (CD) with those of the enantiomers of synthetic 3',4'-dimethoxycinnamoyl analogues. The absolute configuration of one of the synthetic enantiomers was determined using the CD exciton chirality method. This established the structure of naturally occurring 1 as (E)-2,3-dihydroxycyclopentyl-3-(3',4'-dihydroxyphenyl)acrylate.
authors.affiliation: NuBBE, Núcleo de Biossíntese, Bioensaios e Ecofisologia de Produtos Naturais, Instituto de Química, Universidade Estadual Paulista (UNESP), C.P. 355, 14800-900, Araraquara-SP, Brazil.
authors.forename: Carmen Lucia
authors.initials: CL
authors.lastname: Cardoso
authors.forename: Vanderlan da Silva
authors.initials: Vda S
authors.lastname: Bolzani
authors.forename: Dulce Helena Siqueira
authors.initials: DH
authors.lastname: Silva
authors.forename: Hideki
authors.initials: H
authors.lastname: Ishii
authors.forename: Nina
authors.initials: N
authors.lastname: Berova
authors.forename: Koji
authors.initials: K
authors.lastname: Nakanishi
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D003517:Cyclopentanes / Q000737:chemistry*; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism; D014197:Trees / Q000737:chemistry*
chemical_list: C513458:1-(3',4'-dihydroxycinnamoyl)cyclopentane-2,3-diol; D000975:Antioxidants; D003517:Cyclopentanes