Zwitterionic 6-methyl-2-oxo-3-[1-(ureido-iminio)eth-yl]-2H-pyran-4-olate monohydrate

The title compound, C(9)H(11)N(3)O(4)·H(2)O, was prepared by the reaction of dehydro-acetic acid and semicarbazide hydro-chloride. It crystallizes in a zwitterionic form with cationic iminium and anionic enolate groups. In the crystal structure, the almost planar mol-ecules are held together by N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, some of them involving the water molecules.