Gary Martin of Seaton Hall University lead a discussion on 15N NMR for Structure Elucidation. The panelists joining Gary included Mikhail Reibarkh of Merck, Kalindi Morgan of University of North British Columbia, Ron Crouch of JOEL USA, and Tsang-Lin Hwang of Amgen.
Nitrogen is ubiquitous, incorporated in small molecule natural products, pharmaceutical agents, and pharmacologically active peptides. 15N, the spin 1/2 isotope of nitrogen amenable to NMR observation, is notoriously challenging for direct observation with low natural abundance (0.37%) and, relatively speaking, a low observation frequency roughly 10% of the 1H NMR observation frequency on a given NMR instrument with experiments further exacerbated by a negative nOe. Nonetheless, beginning in the early 90’s, it became feasible to perform both one-bond and long-range 1H-15N heteronuclear shift correlation experiments on small samples. The panel discussion will address experiment choices and optimization as well as utilizing 15N NMR data in structure elucidation studies.