Acta Cryst. (2008). E64, o1965-o1966  [ doi:10.1107/S1600536808029498 ]

A second monoclinic polymorph of 4-(2-hydroxy-4-methoxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

Z.-F. Zhu, X.-H. Shen and X.-G. Tang

Abstract: The title compound, C₁₉H₁₉N₃O₃, prepared by condensing 4-aminoantipyrine and 4-methoxy-2-hydroxybenzaldehyde in methanol, is the second monoclinic polymorph of this compound which crystallizes in the space group C2/c. The structure was previously reported [Wang, Zhang, Yan, Zheng & Yang (2007). Acta Cryst. E63, o1245-o1246] in the space group P2₁/c. The hydroxyl group is disordered over two positions with occupancies of 0.787 (4) and 0.213 (4). The triply substituted benzene ring and the phenyl ring form dihedral angles of 12.2 (2) and 53.7 (2)°, respectively, with the pyrazolone ring; the corresponding values in the P2₁/c polymorph are 7.5 (2) and 42.6 (2)°. Intramolecular O-HN and C-HO hydrogen bonds are observed in the major disorder component. Adjacent molecules are linked through intermolecular O-HO hydrogen bonds, forming dimers.

Online 20 September 2008

Copyright © International Union of Crystallography
IUCr Webmaster