Crystal structures of two hydrazide derivatives of mefenamic acid, 3-(2,3-di-methyl-anilino)-N'-[(E)-(furan-2-yl)methyl-idene]benzohydrazide and N'-[(E)-benzyl-idene]-2-(2,3-di-methyl-anilino)benzo-hydrazide.

The conformation about the central benzene ring in the mol-ecule of (I), C20H19N3O2, is partially determined by an intra-molecular N-H⋯O hydrogen bond. In the crystal, chains parallel to the c axis are generated by inter-molecular N-H⋯O hydrogen bonds with the chains assembled into a three-dimensional network structure by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π(ring) inter-actions. The mol-ecule of (II), C22H21N3O, differs from (I) only in the substituent at the hydrazide N atom where a phenyl-methyl-ene moiety for (II) is present instead of a furan-methyl-ene moiety for (I). Hence, mol-ecules of (I) and (II) show similarities in their mol-ecular and crystal structures. The conformation of the central portion of the mol-ecule of (II) is also therefore partially determined by an intra-molecular N-H⋯O hydrogen bond and inter-molecular N-H⋯O hydrogen bonds form chains parallel to the c axis. Likewise, the chains are connected into a three-dimensional network by C-H⋯O hydrogen bonds and C-H⋯π(ring) inter-actions.