(S)-2-[(2R,3S)-2-Ammonio-3-hydr-oxy-3-(4-nitro-phen-yl)propanamido]-4-methyl-penta-noate monohydrate.

The structure of the title compound, C(15)H(21)N(3)O(6)·H(2)O, is of inter-est with respect to assumed anti-cancer activity. The title mol-ecules are linked through inter-molecular O-H⋯O hydrogen-bonded chains along the a axis. These chains are connected by inter-molecular N-H⋯O hydrogen bonds through the crystallographic screw axis along [010], forming layers, which are stabilized by other N-H⋯O bonds with water O atoms as acceptors and O-H⋯O bonds with water H atoms as donors. The H atoms of the protonated amino cation are also involved in inter-molecular N-H⋯O bonding inter-actions.