Crystal structure of (Z)-2-hy­droxy-N′-(4-oxo-1,3-thia­zolidin-2-yl­idene)benzohydrazide

In the title compound, C₁₀H₉N₃O₃S, the five-membered ring adopts a slightly twisted conformation about the C_m—S (m = methyl­ene) bond. The dihedral angle between this ring and the benzene ring is 7.99 (9)°. A bifurcated intra­molecular N—H...(O,S) hydrogen bond helps to establish the near planar conformation of the mol­ecule. In the crystal, mol­ecules are linked by N—H...O and O—H...O hydrogen bonds to generate (001) sheets.

Crystal structure of (Z)-2-hy­droxy-4-methyl-N′-(4-oxo-1,3-thia­zolidin-2-yl­idene)benzohydrazide trihydrate

In the title compound, C₁₁H₁₁N₃O₃S·3H₂O, the non-H atoms of the main mol­ecule are approximately planar, with an r.m.s. deviation of 0.030 Å. There is a bifurcated intra­molecular N—H...(O,S) hydrogen bond present forming S(6) and S(5) ring motifs. In the crystal, O—H...O and N—H...O hydrogen bonds link the molecules into a three-dimensional network.