Conformational Studies of N,N-Disubstituted Nicotinamides. NMR Peak Assignments and Utilization of Shift Reagents with 2,6-Dichloronicotinamides

Article abstract of DOI:10.1021/jo01292a015

Europium-induced shift studies are reported for numerous substituted nicotinamides.Without ring substituents, the europium ion interacts with both the pyridine nitrogen and the amide oxygen; however, with 2,6 ring substituents interaction with the amide oxygen is favored.Simple correlations for the induced shifts of the pyridine ring hydrogens are presented and are useful in the conformational analysis of nicotinamides.A combination of variable-temperature nuclear magnetic resonance (VTNMR) studies and europium shift reagents is used to ascertain the preferred conformation in solution of both simple and complex, substituted nicotinamides.