title: (2S,3R)-2-[(4-Ethyl-2,3-dioxopiperazin-1-yl)carbonyl-amino]-3-hydroxy-butyric acid monohydrate.
abstract: In the title compound, C(11)H(17)N(3)O(6)·H(2)O, an important building block of the medicine cefbuperazone sodium, the piperazine ring adopts a screw-boat conformation. Inter-molecular O-H⋯O and intra-molecular N-H⋯O hydrogen bonds are observed. The water mol-ecule participates as both donor and acceptor in this framework.
authors.forename: Chun-Xiang
authors.initials: CX
authors.lastname: Ji
authors.forename: Yong-Tao
authors.initials: YT
authors.lastname: Cui
authors.forename: Dong-Ling
authors.initials: DL
authors.lastname: Yang
authors.forename: Cheng
authors.initials: C
authors.lastname: Guo