Computational studies on the conformational preference of N-(Thiazol-2-yl) benzamide

N-(Thiazol-2-yl) benzamide 1 substructures are found in some of bioactive compounds. In some of protein/ligand co-crystals, the 1 moiety adopts a conformer in which the amide O and the thiazole S atoms are close. In fact, in the crystalline structure of 1, the O-S distance is even shorter than Van der Waals radius. Although the natural bond orbital analysis finds a weak stabilizing interaction between O and S atoms, the attractive dipole-dipole interaction between the amide N & x2500;H and thiazole N atom seems to play a more significant role. Moreover, an intramolecular O-H hydrogen bonding in dimeric forms found to have an important role in the conformation preference of 1. Computational details for the stability of conformers have been discussed using quantum theory of atoms in molecules, natural bond orbital (NBO) and noncovalent interaction index analysis.