N2-(4-Methoxysalicylidene)arginine hemihydrate

Abstract

The title compound, C14H20N4O4·0.5H2O [systematic name: (2S)-5-{[amino(iminiumyl)methyl]amino}-2-{[(1Z)-4-methoxy-2-oxidobenzylidene] azaniumyl}pentanoate hemihydrate], has been synthesized by the reaction of l-arginine and 4-methoxysalicylaldehyde and crystallizes with two independent substituted l-arginine molecules and one water molecule of solvation in the asymmetric unit. Each molecule exists as a zwitterion and adopts a Z configuration about the central C=N. The molecular conformation is stabilized by strong intramolecular N - H⋯O hydrogen bonds that generate S(6) and S(10) ring motifs. Intermolecular N - H⋯O and O - H⋯O hydrogen bonds involving also the water molecule and weak intermolecular C - H⋯Owater interactions link the molecules into an infinite one-dimensional ribbon structure extending along the b axis. The known (2S) absolute configuration for l-arginine was invoked. Weak intermolecular C - H⋯π interactions are also present.