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 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.

Keywords

• crystal structure
• 4-aminoantipyrine
• aerial oxidation
• dimethylformamide
• hydrogen bonding
• hirshfeld surface