Acta Cryst. (2002). E58, o787-o789  [ doi:10.1107/S160053680201098X ]

2,5-Dihydro-3,4-dimethyl-5-oxo-1H-pyrazole-1-carbothioamide

R. Carballo, J. S. Casas, E. García-Martínez, G. Pereiras-Gabián, A. Sánchez, J. Sordo and E. M. Vázquez-López

Abstract: The title compound, C₆H₉N₃OS, was obtained by cyclization of ethyl 2-methylacetoacetate thiosemicarbazone with sodium methanolate in methanol. Single crystals suitable for X-ray analysis were obtained by slow evaporation of the mother liquor. The pyrazolone moiety is essentially planar. The S atom is cis with respect to the protonated endocyclic N² atom, probably because the intramolecular hydrogen bonds allowed by this arrangement afford greater stability than those allowed when S is trans to N-2. Intermolecular hydrogen bonds link the molecules in interlocking pleated sheets, stacked along the c axis.

Online 29 June 2002

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