title: Ultra-high resolution band-selective HSQC for nanomole-scale identification of chlorine-substituted13C in natural products drug discovery.
abstract: Ultra-high resolution band-selective HSQC (bsHSQC) has been employed for detection of35Cl-37Cl isotope shifted13C NMR signals for assignment of regioisomerism in bromo-chloro natural products. Optimum pulse sequence and instrumental parameters for maximization of detection of the isotope shifts were explored. The chlorine isotope shifts (Δδ) were detected within crosspeaks and were shown to vary with hybridization of13C, substitution of13C, presence of β-chloro substituents, and their relative configuration. Deconvolution of Cl-substituted CH bsHSQC crosspeaks may provide other useful information, including a potentially MS-independent method for quantitating37Cl/35C isotopic fractionation during the biosynthesis of halogenated natural products. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr. MC-0358, La Jolla, CA, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Dr. MC-0358, La Jolla, CA, USA.
authors.forename: Brendan M
authors.initials: BM
authors.lastname: Duggan
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr. MC-0358, La Jolla, CA, USA.|Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Dr. MC-0358, La Jolla, CA, USA.
authors.forename: Tadeusz F
authors.initials: TF
authors.lastname: Molinski
mesh_terms: D001688:Biological Products / Q000737:chemistry*; D002247:Carbon Isotopes; D005591:Chemical Fractionation; D002713:Chlorine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D007554:Isotopes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure
chemical_list: D001688:Biological Products; D002247:Carbon Isotopes; D007554:Isotopes; D002713:Chlorine
keywords: 13C; 1H; 35Cl; 37Cl; HSQC; NMR; Rhodophyta; isotope shift; natural product; terpene