(Z)-4-[2-(2,4-Dimethylphenyl)hydrazinylidene]-3-methylpyrazol-5(1H)-one

Abstract

The mol­ecule of the title compound, C12H14N4O, is roughly planar, with a dihedral angle of 8.0 (8)° between the benzene and pyrazole rings, and an intra­molecular N—H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, mol­ecules are linked into an inversion dimer by a pair of N—H⋯O hydrogen bonds, which form an R 2 2(8) ring motif.

(Z)-4-[2-(3,4-Difluorophenyl)hydrazono]-3-methyl-1H-pyrazol-5(4H)-one

“…The broad peak for exocyclic NH of the hydrazono group appeared in the downfield at δ 13.03 ppm. The downfield shift could be due to the intramolecular hydrogen bond between the exocyclic N-H of the hydrazono group with the oxygen of the carbonyl group of the pyrazolone ring, which was further supported by the single crystal X-Ray diffraction structure of an analogue 5-methyl-4-(2-(2,4-dimethylphenylhydrazinylidene)-2,4-dihydro-3H-pyrazol-3-one [24]. Normally, a pyrazolone molecule exhibits tautomerism due to the presence of -NH-C=O adjacent groups in a ring, as shown in Figure 1.…”

“…Found: C, 50.35; H, 3.30; N, 23.59. The analogues of compound 4-(Z)-4-[2-(2,4-dimethylphenyl)hydrazono]-3-methyl-1H-pyrazol-5(4H)-one (PYZ-di-CH 3 ) and (Z)-4-[2-(4-fluorophenyl)hydrazono]-3-methyl-1H-pyrazol-5(4H)-one (PYZ-F)-were prepared by the reported procedure[24,27].…”