5-Amino-4-methyl­sulfonyl-1-phenyl-1H-pyrazole

The title compound, C₁₀H₁₁N₃O₂S, was designed and synthesized as a potential antitumour agent and a single-crystal X-ray analysis was undertaken to determine the three-dimensional arrangement of the putative pharmacophoric groups. The central pyrazole ring is exactly planar and the 1-phenyl group has no effect on the π-electron system of the pyrazole nucleus. In contrast, the 5-amino N atom is strongly conjugated with the pyrazole ring such that the flow of the resulting negative charge is in the direction of the 4-sulfonyl O atoms. All of the potential hydrogen-bond donors and acceptors are actually involved in hydrogen bonding.