Molecular recognition on crystallization of enantiopure and racemic N-benzoylalanine methyl ester

The melting points of crystals of (S)- and (RS)-N-benzoylalanine methyl est er derived from solutions of ethyl acetate/light petroleum are 56-57.5 degr ees and 81.5-82.5 degrees, respectively, reflecting differences in lattice energy that are apparent from the crystal structures. A more extensive mode of association between chains, uniformly stabilized by N-H O-C interaction s, is found in the racemate leading to a more efficient packing of molecule s. The higher lattice energy of the racemate has been confirmed through the enantiomeric enrichment of an optically active sample and the partial reso lution of (RS)-N-benzoyl(2-H-2) alanine methyl ester, through molecular rec ognition on crystallization.