4-[(Z)-(n-Butylamino)(phenyl)methylidene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

Abstract

The title compound, C21H23N3O, exists in an enamine–keto form with the amino group involved in an intramolecular N—H...O hydrogen bond. The dihedral angle between the phenyl rings is 73.59 (6)°. The five-membered ring is nearly planar, the largest deviation being 0.0004 (7) Å, and makes dihedral angles of 4.81 (6) and 69.81 (5)° wth the phenyl rings. In the crystal, pairs of weak C—H...O interactions link the molecules into centrosymmetric dimers.