title: Systematic comparison of sets of (13)C NMR spectra that are potentially identical. Confirmation of the configuration of a cuticular hydrocarbon from the cane beetle Antitrogus parvulus.
abstract: A systematic process is introduced to compare (13)C NMR spectra of two (or more) candidate samples of known structure to a natural product sample of unknown structure. The process is designed for the case where the spectra involved can reasonably be expected to be very similar, perhaps even identical. It is first validated by using published (13)C NMR data sets for the natural product 4,6,8,10,16,18-hexamethyldocosane. Then the stereoselective total syntheses of two candidate isomers of the related 4,6,8,10,16-pentamethyldocosane natural product are described, and the process is applied to confidently assign the configuration of the natural product as (4S,6R,8R,10S,16S). This is accomplished even though the chemical shift differences between this isomer and its (16R)-epimer are only ±5-10 ppb (±0.005-0.01 ppm).
authors.affiliation: Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia , Skudai, 81310 Johor, Malaysia.
authors.forename: Norazah
authors.initials: N
authors.lastname: Basar
authors.forename: Krishnan
authors.initials: K
authors.lastname: Damodaran
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.forename: Gareth A
authors.initials: GA
authors.lastname: Morris
authors.forename: Hasnah M
authors.initials: HM
authors.lastname: Sirat
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Thomas
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Curran
mesh_terms: D000473:Alkanes / Q000138:chemical synthesis* / Q000737:chemistry; D000818:Animals; D001688:Biological Products / Q000737:chemistry*; D001517:Coleoptera / Q000737:chemistry*; D006838:Hydrocarbons / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: C492633:4,6,8,10,16,18-hexamethyldocosane; C492632:4,6,8,10,16-pentamethyldocosane; D000473:Alkanes; D001688:Biological Products; D006838:Hydrocarbons