Chiral Resolution of Aspartic Acid Racemate by Single Crystallization With Phenylalanine as Additive

The effective chiral resolution of amino acid racemates has important significance in fields such as medicine and pharmaceuticals. By using phenylalanine as additive, the chiral resolution of aspartic acid racemate was investigated through crystallization method. It reveals that the enantiomeric excess of the crystalline product is affected by the seeding temperature, crystallization temperature, crystallization time, seed dosage, phenylalanine dosage, and the relative supersaturation. Under optimized condition, the average enantiomeric excess could reach 85% after a single crystallization in water. The excess enantiomer of the crystalline product is determined by the configuration of phenylalanine. The enantiomeric excess and the excess enantiomer were confirmed by chiral high performance liquid chromatography. The powder X-ray diffraction and Fourier transform infrared spectral results show that conglomerate was formed in the crystalline product. Seed and additive both play great role in the chiral resolution. The findings could give inspirations for efficient resolution of aspartic acid racemate into enantiopure compounds.