Racemic mandelic acid (2) was resolved efficiently by complexation with (S)-(+)-alanine (1) and the crystal structure of 2:2:1 complex of (S)-(+)-alanine (1), (R)-(-)-mandelic acid (2) and H2O was determined characterizing the hydrogen bond network in the solid state.
RogerR., J. Chem. Soc., 1935, 1544; A. Collet, J. Jacques, Bull. Soc. Chim. Fr., 1972, 12, 3330; E. J. Valente, W. M. Christopher, J. Zubkowski, D. S. Eggleston, X. Shui, Chirality, 1995, 7, 652.