title: Resolution and absolute configuration assignment of a natural racemic chromane from Peperomia obtusifolia (Piperaceae).
abstract: The resolution of the natural racemic chromane 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3''-methyl-2''-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylic acid (1) isolated from the leaves of Peperomia obtusifolia has been accomplished using stereoselective HPLC. The absolute configuration of the resolved enantiomers was determined by the analysis of optical rotations and CD spectra. The finding of a racemic mixture instead of an enantiomerically pure metabolite raises questions about the final steps in the biosynthesis of this class of natural products, suggesting that the intramolecular chromane ring formation step may not be enzymatically controlled at all in P. obtusifolia.
authors.affiliation: Nucleus for Bioassays, Biosynthesis and Ecophysiology of Natural Products, Organic Chemistry Department, Institute of Chemistry, São Paulo State University, Araraquara, SP, Brazil.
authors.forename: João Marcos
authors.initials: JM
authors.lastname: Batista
authors.forename: Silvia Noelí
authors.initials: SN
authors.lastname: López
authors.forename: Jonas da Silva
authors.initials: Jda S
authors.lastname: Mota
authors.forename: Kenia Lourenço
authors.initials: KL
authors.lastname: Vanzolini
authors.forename: Quezia Bezerra
authors.initials: QB
authors.lastname: Cass
authors.forename: Daniel
authors.initials: D
authors.lastname: Rinaldo
authors.forename: Wagner
authors.initials: W
authors.lastname: Vilegas
authors.forename: Vanderlan da Silva
authors.initials: Vda S
authors.lastname: Bolzani
authors.forename: Massuo Jorge
authors.initials: MJ
authors.lastname: Kato
authors.forename: Maysa
authors.initials: M
authors.lastname: Furlan
mesh_terms: D001578:Benzopyrans / Q000737:chemistry* / Q000302:isolation & purification; D001688:Biological Products / Q000737:chemistry* / Q000302:isolation & purification; D002839:Chromans / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D009904:Optical Rotation; D036941:Peperomia / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: C545838:3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3''-methyl-2''-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylic acid; D001578:Benzopyrans; D001688:Biological Products; D002839:Chromans