Hydrogen bonding and pi-pi stacking in 7-{2-[4-(4-methoxyphenyl)piperazin-1-yl]ethoxy}-4-methyl-2H-chromen-2-one monohydrate.

In the title compound, C23H26N2O4.H2O, the benzopyran ring system is planar. The piperazine ring adopts an almost perfect chair conformation, and the methoxy group is coplanar with its parent benzene ring. Hydrogen bonds link two water molecules and two piperazine molecules into tetrameric units. The adjacent benzopyran moieties within these units also interact via pi-pi stacking interactions, and a sheet is formed by the propagation of these interactions. The bioassay results have shown alpha1-adrenoceptor antagonistic activity through in vitro animal experiments.