Acta Cryst. (2009). E65, o330  [ doi:10.1107/S1600536809001470 ]

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

T. U. Sheikh, M. A. Khan, M. N. Arshad, I. U. Khan and H. Stoeckli-Evans

Abstract: 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-HO 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-HN interaction. There are also some weak C-H interactions involving the phenyl ring of molecule A and H atoms of the acetyl groups of both molecules.

Online 17 January 2009

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