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.