title: (E)-N-Butyl-3-(3,4-dihy-droxy-phen-yl)acryl-amide hemihydrate.
abstract: In the title compound, C(13)H(17)NO(3)·0.5H(2)O, a new caffeic acid amide derivative, the solvent water mol-ecule lies on a twofold axis and the terminal ethyl group appears disordered with occupancy factors of 0.525 (6) and 0.475 (6). The benzene ring makes an angle of 17.3 (2)° with the C=C-C-O linker. The presence of an ethyl-enic spacer in the caffeic acid amide mol-ecule allows the formation of a conjugated system, strongly stabilized through π-electron delocalization. The C=C double bond in the linker is trans, similar to those previously reported in caffeic esters. The crystal is stabilized by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds. The mol-ecules of the caffeic acid amide form a supermolecular planar structure through O-H⋯O hydrogen bonds between a hy-droxy group of one caffeic acid mol-ecule and a carbonyl O atom of another. These planes inter-act via C-H⋯O, O-H⋯O and N-H⋯O hydrogen bonds to form a three-dimensional network.
authors.affiliation: College of Chemistry and Chemical Engineering, Xinxiang University, Xinxiang, Henan 453003,  People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Han
authors.forename: Mi-Hua
authors.initials: MH
authors.lastname: Hao