SUCCESSIVE OPTICAL RESOLUTION BY REPLACING CRYSTALLIZATION OF DL-THREONINE

DL-Threonine [DL-Thr; (2RS, 3SR)-2-amino-3-hydroxybutanoic acid] was o ptically resolved by replacing crystallization using L-serine (L-Ser) and I-hydroxy-L-proline (L-Hyp) as optically active cosolutes. D-Thr w as allowed to crystallize preferentially from racemic aqueous solution s in the presence of these L-alpha-amino acids, The optical resolution of DL-Thr was more successfully achieved by using L-Ser, whose struct ure is more similar to that of DL-Thr than L-Hyp, and successively gav e D- and L-Thr of 87-92% optical purities. The D- and L-Thr obtained w ere then recrystallized from water to give optically pure D- and L-Thr . (C) 1994 Wiley-Liss, Inc.