Ethyl 3-oxo-2-(2-phenyl-hydrazinyl-idene)butano-ate: a re-determination.

The previous crystallographic studies [Wang et al. (2005 ▶). Huaxue Yanjiu16, 29-32; Wang et al. (2007 ▶). Youji Huaxue, 27, 524] of the title compound, C(12)H(14)N(2)O(3), gave only the unit-cell dimensions and an R factor with no other details available: the full structure is presented here. The eth-oxy group is disordered over two orientations with refined occupancies of 0.642 (15):0.358 (15). The nine C atoms and two N atoms of the 1-phenyl-2-(propan-2-yl-idene)hydrazine segment of the mol-ecule are close to being coplanar, with a maximum deviation of 0.0779 (14) Å for the phenyl-amino N atom and an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, pairs of C-H⋯O hydrogen bonds link mol-ecules into inverson dimers, generating R(2) (2)(16) loops.