A second monoclinic polymorph of 4-(2-hydr-oxy-4-methoxy-benzyl-ideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one.

The title compound, C(19)H(19)N(3)O(3), prepared by condensing 4-amino-anti-pyrine and 4-meth-oxy-2-hydroxy-benzaldehyde 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 P2(1)/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 P2(1)/c polymorph are 7.5†(2) and 42.6†(2)°. Intra-molecular O-H⋯N and C-H⋯O hydrogen bonds are observed in the major disorder component. Adjacent molecules are linked through intermolecular O-H⋯O hydrogen bonds, forming dimers.