4-[(<i>E</i>)-(2,4,5-Trimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1<i>H</i>-pyrazol-3(2<i>H</i>)-one

The title compound, C(21)H(23)N(3)O(4), adopts an E configuration about the central C=N double bond and the pyrazolone ring is almost planar, with a maximum deviation of 0.042 (1) Å. The central pyrazolone ring makes dihedral angles of 51.96 (5) and 3.82 (5)° with the attached phenyl and the trimeth-oxy-substituted benzene rings, respectively. The dihedral angle between the phenyl ring and the trimeth-oxy-substituted benzene ring is 50.19 (5)° and an intra-molecular C-H⋯O hydrogen bond generates an S(6) ring motif. The crystal structure is stabilized by inter-molecular C-H⋯O and C-H⋯N hydrogen bonds.