Crystal structure of 4-((4-methoxy-benzylidene)-amino)-1,5-dimethyl- 2-phenylpyrazolidin-3-ol, C19H19N3O2

Abstract

Source of material p-Methoxybenzaldehyde (0.1 mmol, 13.6 mg) and 4-aminoantipyrine (0.1 mmol, 20.3 mg) were dissolved in methanol (10 ml). The mixture was stirred for 30 min at room temperature to give a clear yellow solution. After allowing the resulting solution to stand in air for 7 d, yellow flake-shaped crystals were formed at the bottom of the vessel by slow evaporation of the solvent. The crystals were isolated by filtration, washed with methanol and dried in a vacuum desiccator using anhydrous CaCl2 (yield 54 %). Elemental analysis found: C, 58.1 %; H, 5.5 %; calculated for C18H16N4O3: C, 58.2 %; H, 5.6 %. DiscussionAntipyrine and antipyridine derivatives in biological processes have become a topic of study in recent years [1][2][3]. The title compound is a new representative of antipyrine Schiff bases. All bond lengths and angles are in agreement with those in similar antipyrine Schiff bases. The pyrazoline ring is essentially planar. The dihedral angle between pyrazoline ring and C14®C19 phenyl ring is 46.8(5)°. The N3N2C14C19 and C1N1C14C15 torsion angles are 155.7(2)°and 118.9(3)°, respectively. The O1 atom deviates from the pyrazoline mean plane by 0.109(3) Å, whereas the C4 and C5 atoms deviate from it on the opposite side by 0.581(8) Å and 0.149(7) Å, respectively. The C6N1 bond length of 1.277(3) Å conforms to the value for a double bond. Because of conjugation through the imine double bond, C6N1, the pyrazoline and C14®C19 substituted phenyl rings are approximately coplanar (mean deviation from the overall plane is 0.025(3)°), the dihedral angle between the two rings is 11.4(5)°. As expected, the molecular structure adopts a trans configuration around the C6N1 bond.Z. Kristallogr.

Structural characterization of hydrogen bonding for antipyrine derivatives: Single-crystal X-ray diffraction and theoretical studies

“…They form a large number of complexes with alkaline-, transition-, and rare-earth metals [1][2][3][4][5][6][7][8]. From this point of view, searching for new ligands (including representatives of antipyrine-based ones) is very important [4,9]. Using the method of computer prognosis based on the Prediction of Activity Spectra for Substances (PASS) system [10], it has been demonstrated that some pyrazolone derivatives, such as 5-methyl-2-phenyl-4H-pyrazol-3-one (compound I) and 2-(4-chlorophenyl)-5-methyl-4H-pyrazol-3-one (compound II), possess a relatively high probability of antimetastatic activity.…”