title: 15N chemical shifts of a series of isatin oxime ethers and their corresponding nitrone isomers.
abstract: In this article, we describe the characteristic (15)N chemical shifts of isatin oxime ethers and their isomer nitrone. These oxime ethers and nitrones are the alkylation reaction products of isatin oximes. In our study, the (15)N chemical shifts observed in these oxime ethers were in the 402-408 (or 22-28) ppm range, although those for their corresponding nitrone series were in the 280-320 (or -100 to -60) ppm range. This remarkable difference in (15)N NMR chemical shift values could potentially be used to determine the O- versus N-alkylation of oximes, even when only one isomer is available. In this paper, the differences in (15)N NMR chemical shifts serve as the basis for a discussion about how to distinguish both regioisomers derived from the oximes alkylation.
authors.affiliation: Department of Drug Metabolism, Covance Company, 3301 Kinsman Boulevard, Madison, WI 53704, USA.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
authors.forename: Xiaohua Stella
authors.initials: XS
authors.lastname: Huang
authors.forename: Ny
authors.initials: N
authors.lastname: Sin
authors.forename: Brian L
authors.initials: BL
authors.lastname: Venables
authors.forename: Vikram
authors.initials: V
authors.lastname: Roongta
mesh_terms: D000478:Alkylation; D004583:Electrons; D004987:Ethers / Q000138:chemical synthesis / Q000737:chemistry*; D007510:Isatin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D015394:Molecular Structure; D009587:Nitrogen Isotopes; D009589:Nitrogen Oxides / Q000138:chemical synthesis / Q000737:chemistry*; D010091:Oximes / Q000138:chemical synthesis / Q000737:chemistry*; D012015:Reference Standards; D013237:Stereoisomerism
chemical_list: D004987:Ethers; D009587:Nitrogen Isotopes; D009589:Nitrogen Oxides; D010091:Oximes; C015388:nitrones; D007510:Isatin