(4Z)-4-[1-(2-Aminoanilino)ethylidene]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one

Abstract

The conformation of the title compound, C18H18N4O, is partly determined by an intramolecular N—H...O hydrogen bond that imposes planarity on the central aminoethylidene-3-methylpyrazol-5-one segment of the molecule. In the crystal, N—H...O hydrogen and N—H...N hydrogen bonds both form centrosymmetric dimers that encloseR22(18) rings. These, together with C—H...N and π–π stacking interactions between centrosymmetrically related pyrazalone rings, stack the molecules along theb-axis direction.