(RS)-α-Amino-γ-butyrolactone hydrochloride [(RS)-ABL· HCl] was found to exist as a conglomerate based on the infrared spectrum, solubility, and melting point. Optical resolution by preferential crystallization of (RS)-ABL· HCl was achieved to yield (R)-and (S)- ABL· HCl. The obtained (R)-and (S)-ABL· HCl were recrystallized, taking into account the solubility of (RS)-ABL· HCl to give optically pure (R)-and (S)-ABL· HCl.
[Jamieson, Andrew G.; Boutard, Nicolas; Beauregard, Kim; Bodas, Mandar S.; Ong, Huy; et al. Journal of the American Chemical Society, 2009 , vol. 131, p. 7917 - 7927]