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

The title compound, C12H12N2O2, crystallized in the monolinic space group P21/n, with two independent mol­ecules (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 mol­ecule per asymmetric unit. The dihedral angles between the two rings differ slightly; in mol­ecule A it is 4.90 (11)° and in mol­ecule B it is 16.05 (13)°. In both mol­ecules, there is an intra­molecular O—H⋯O hydrogen bond involving the hydroxyl substituent and the carbonyl O atom of the adjacent acetyl group. In the crystal structure, mol­ecules A and B are linked via a C—H⋯N inter­action. There are also some weak C—H⋯π inter­actions involving the phenyl ring of mol­ecule A and H atoms of the acetyl groups of both mol­ecules