1-(5-Hydr-oxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)ethanone: a new monoclinic polymorph.

The title compound, C(12)H(12)N(2)O(2), crystallized in the monolinic space group P2(1)/n, with two independent mol-ecules (A and B) in the asymmetric unit. This is in contrast to the first monoclinic polymorph reported [Cingolani et al. (2002 ▶). Inorg. Chem.41, 1151-116], which crystallized in the space group C2/c with one independent mol-ecule per asymmetric unit. The dihedral angles between the two rings differ slightly; in mol-ecule A it is 4.90 (11)° and in mol-ecule B it is 16.05 (13)°. In both mol-ecules, there is an intra-molecular O-H⋯O hydrogen bond involving the hydroxyl substituent and the carbonyl O atom of the adjacent acetyl group. In the crystal structure, mol-ecules A and B are linked via a C-H⋯N inter-action. There are also some weak C-H⋯π inter-actions involving the phenyl ring of mol-ecule A and H atoms of the acetyl groups of both mol-ecules.