Nature Of Nitrogen Atoms Research Articles

One more chiral drug prone to spontaneous resolution: Binary phase diagram, absolute configuration, and crystal packing of bevantolol hydrochloride

Spontaneous resolution of cardioselective β 1-adrenergic blocker bevantolol hydrochloride 1·HCl was established by IR spectroscopy, differential scanning calorimetry, and by single crystal X-ray analysis both for enantiopure and racemic samples. The absolute configuration of 1·HCl was evaluated through Flack parameter method. The molecular structure and crystal packing details were evaluated; the symmetry independent fragment of the P1 unit cell consists of two molecules which have almost identical spatial arrangement, but differ sufficiently in the nature of nitrogen atoms: quaternary form in one case and free amine form in the other.

Effect of Ligand Structure on Activation Rate Constants in ATRP

Activation rate constants (kact) for Cu complexes with various nitrogen-based ligands for Cu-mediated ATRP were determined at 35 °C in acetonitrile. The ratio of kact for complexes with different ligands exceeds 1 million times. The general order of Cu complex activity for ligands is tetradentate (cyclic-bridged) > tetradentate (branched) > tetradentate (cyclic) > tetradentate (linear) > tridentate > bidentate ligands. The nature of nitrogen atoms in ligands also plays a significant role in the activity of the Cu complexes and follows the order pyridine ≥ aliphatic amine > imine.