15N chemical shifts of a series of isatin oxime ethers and their corresponding nitrone isomers |
| |
| Authors: | Xiaohong Liu Xiaohua Stella Huang Ny Sin Brian L Venables Vikram Roongta |
| |
| Institution: | 1. Department of Drug Metabolism, Covance Company, 3301 Kinsman Boulevard, Madison, WI 53704, USA;2. Department of Bioanalytical and Discovery Analytical Sciences, Bristol‐Myers Squibb Research and Development, 5 Research Parkway, Wallingford, CT 06492, USA;3. Department of Chemistry, Bristol‐Myers Squibb Research and Development, 5 Research Parkway, Wallingford, CT 06492, USA;4. Department of Bioanalytical Sciences, Bristol‐Myers Squibb Research and Development, Route 206 and Province Line Road, Princeton, NJ 08543, USA |
| |
| Abstract: | In this article, we describe the characteristic 15N 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 15N 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 15N 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 15N NMR chemical shifts serve as the basis for a discussion about how to distinguish both regioisomers derived from the oximes alkylation. Copyright © 2010 John Wiley & Sons, Ltd. |
| |
| Keywords: | NMR N‐15 NMR 15N chemical shifts long‐range H?N coupling constant oxime nitrone alkylation of oximes |
|
|
