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

Spontaneous resolution of cardioselective β1-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.