Structure of (<i>E</i>)-4-amino-5-{[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1<i>H</i>-pyrazol-4-yl)imino]methyl}-1-methyl-2-phenyl-2,3-dihydro-1<i>H</i>-pyrazol-3-one: aerial oxidation of 4-aminoantipyrine in dimethylformamide

The title compound, C₂₂H₂₂N₆O₂ (<b>I</b>), is the result of the aerial oxidation of the 5-methyl group of 4-amino-anti-pyrine to an aldehyde group followed by Schiff base formation with a second mol-ecule of 4-amino-anti-pyrine. The reaction only takes place in the presence of di-methyl-formamide. The central unit of the mol-ecule is close to planar, the pyrazole rings being inclined to each other by 3.74 (15)°. There is an intra-molecular N-H⋯N hydrogen bond enclosing an <i>S</i>(6) ring motif and there are two further <i>S</i>(6) rings involving weak C-H⋯O=C hydrogen bonds. The mol-ecule has an <i>E</i> configuration about the azomethine (-N=CH-) bond. In the crystal, inversion-related mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming dimers enclosing <i>R</i> ² ₂(10) loops. The dimers are linked by C-H⋯O hydrogen bonds and C-H⋯π inter-actions, leading to the formation of a three-dimensional supra-molecular network.