Crystal structure of (Z)-N′-[1-(3-methyl-5-oxo-1-phenyl-1,5-di­hydro-4H-pyrazol-4-yl­idene)prop­yl]benzene­sulfono­hydrazide

The title compound, C(19)H(20)N(4)O(3)S, was synthesized by refluxing equimolar amounts of 1-phenyl-3-methyl-4-propionylpyrazol-5-one and benzene­sulfonyl hydrazide in ethanol. The compound crystallizes in the keto form and the carbonyl O atom forms an intra­molecular N—H⋯O hydrogen bond with the neighbouring NH group. There is also C—H⋯O short contact involving the neighbouring phenyl ring. Probably as a result of this, the phenyl ring is inclined to the pyrazolone ring by only 7.58 (12)°. The dihedral angle between the phenyl ring and the benzene­sulfonyl ring is 22.78 (11)°. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R (2) (2)(14) ring motif. The dimers are linked via pairs of C—H⋯O hydrogen bonds, forming chains propagating along [100].