NMR of the Enaminones

Nuclear Magnetic Resonance (NMR) spectroscopy has advanced as an important tool in support of several studies of pharmacological interest. In this chapter, the following sections are discussed: the history of NMR spectroscopy, the enaminone derivatives and their NMR, the use of molecular modeling techniques as an adjunct to NMR analysis, and a newer class of compounds, the sulfonamide enaminones and their intermolecular forces determined via NMR and X-ray crystallography. The history of NMR spectroscopy details the field of NMR, its origin, and utilization in the area of structure identification. The section on NMR spectroscopy of the enaminones gives a detailed look into the use of NMR in the area of analyzing various enaminone analogs, including our library of anticonvulsant enaminones. Examples of enaminones and NMR include the work of Zhou in noting the correlation between the 17O (which has natural abundance) chemical shifts of the carbonyl atom and the 1H chemical shifts. Our work on enaminones analogs was complemented by NMR spectroscopy with examples of how reactions were determined by NMR analyses. The section on molecular modeling aspects as an adjunct to the NMR field explains how the use of Gaussian 03 performs suitable functions in determining the final structure and gives reason to why some compounds in a series are more potent than others. The final section illustrates the newer sulfonamido enaminones now being researched as potential anticonvulsant agents and how their pharmacological profile (having 6 Hz ‘psychomotor’ activity) differs from the previously investigated anticonvulsant enaminone derivatives.

Keywords: 6 Hz psychomotor, Aniline, Anticonvulsant, CLogP, Comparative molecular field analysis (CoMFA), Comparative molecular similarity indices analysis (CoMSIA), Dimedone, Drug design, Enaminones, Gaussian, Hydrogen bonding, Intermolecular forces, Maximal electroshock seizures (MES), NMR spectroscopy, Pharmacophore, Phenytoin, Protein dynamics, Structure activity relationship, Subcutaneous pentylenetetrazol (scPTZ), X-ray crystals.