Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA) was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides.

One of six 2-alkylamino-4,6-dimethylnicotinamides afforded a conglomerate, and subsequent X-ray crystallographic analysis revealed that the compound crystallized in the monoclinic system, the space group P21. Crystallization of the racemic nicotinamide from the melt led to the chiral breaking of symmetry from 83 to 92% ee. This amide exhibited considerably stable axial chirality (ΔG‡: 22.4–23.5 kcal mol−1 at 20 °C) due to rotationally restricted scaffolds for the C–C(=O) bond.