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

Abstract

The formation of the title compound is best explained by the aerial oxidation of the 5-methyl group of 4-amino­anti­pyrine to an aldehyde group, and subsequent inter­molecular Schiff base formation with a second mol­ecule of 4-amino­anti­pyrine. The reaction only takes place in the presence of di­methyl­formamide.

The title compound, C₂₂H₂₂N₆O₂ (I), is the result of the aerial oxidation of the 5-methyl group of 4-amino­anti­pyrine to an aldehyde group followed by Schiff base formation with a second mol­ecule of 4-amino­anti­pyrine. The reaction only takes place in the presence of di­methyl­formamide. The central unit of the mol­ecule is close to planar, the pyrazole rings being inclined to each other by 3.74 (15)°. There is an intra­molecular N—H⋯N hydrogen bond enclosing an S(6) ring motif and there are two further S(6) rings involving weak C—H⋯O=C hydrogen bonds. The mol­ecule has an E configuration about the azomethine (—N=CH—) bond. In the crystal, inversion-related mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming dimers enclosing R²₂(10) loops. The dimers are linked by C—H⋯O hydrogen bonds and C—H⋯π inter­actions, leading to the formation of a three-dimensional supra­molecular network.