Synthesis, structures and Hirshfeld surface analyses of 2-hy-droxy-'-methyl-acetohydrazide and 2-hy-droxy--methyl-acetohydrazide.

The structures of the title compounds 2-hy-droxy-'-methyl-acetohydrazide, , and 2-hy-droxy--methyl-acetohydrazide, , both CHNO, as regioisomers differ in the position of the methyl group relative to the N atoms in 2-hy-droxy-acetohydrazide. In the structure of , the 2-hy-droxy-acetohydrazide core [OH-C-C(=O)-NH-NH] is almost planar and the methyl group is rotated relative to this plane. As opposed to , in the structure of all non-hydrogen atoms lie in the same plane. The hydroxyl and carbonyl groups in structures and are in and positions, respectively. The methyl amino group and carbonyl group are in the position relative to the C-N bond in structure , while the amino group and carbonyl group are in the position relative to the C-N bond in stucture In the crystal, mol-ecules of are linked by N-H⋯O and O-H⋯N inter-molecular hydrogen bonds, forming layers parallel to the crystallographic plane. A Hirshfeld surface analysis showed that the H⋯H contacts dominate the crystal packing with a contribution of 55.3%. The contribution of the H⋯O/O⋯H inter-action is somewhat smaller, amounting to 30.8%. In the crystal, as a result of the inter-molecular O-H⋯O hydrogen bonds, mol-ecules of form dimers, which are linked by N-H⋯O hydrogen bonds and a three-dimensional supra-molecular network The major contributors to the Hirshfeld surface are H⋯H (58.5%) and H⋯O/O⋯H contacts (31.7%).