Acta Crystallographica Section E
Volume 63, Issue 5, pages o2554–o2556, May 2007
How to Cite
Baryala, Y., Zerzouf, A., Essassi, E. M., Reuter, H. and Eickmeier, H. (2007), 4-[(3-Hydroxy-5-phenyl-1H-pyrazol-4-yl)methyl]-5-phenyl-1H-pyrazol-3(2H)-one. Acta Crystallographica E, 63: o2554–o2556. doi: 10.1107/S1600536807018387
The solid-state structure of the title compound, C19H16N4O2, is dominated by the keto–enol tautomerization of its two 1H-pyrazol-3-one moieties. Since all H atoms could be located in a difference Fourier synthesis, it was possible to distinguish the enol form from the keto form unambiguously. As a result of this tautomerization, an intramolecular hydrogen bond embedded in an eight-membered ring is formed. The two-dimensional hydrogen-bonding system results from three additional intermolecular hydrogen bonds of different strengths, all involved in eight- and ten-membered ring systems.