Synthesis and structure of 1-[(3-hydroxybenzo[b]thiophen-2-yl)methylidene]-3-oxo-5-phenyl-1-pyrazolidinium-2-ide

Resumo

Potentially tautomeric azomethine imine, 1-[(3-hydroxybenzo[b]thiophen-2-yl)methylidene]-3-oxo-5-phenyl-1-pyrazolidinium-2-ide has been prepared. According to X-ray diffraction, ¹H, ¹³C, and ¹⁵N NMR and electronic spectroscopy, the compound exists as 3-hydroxybenzothiophene structure containing intermolecular hydrogen bond between the hydroxy group and the carbonyl oxygen of the pyrazolidone ring in crystal state. Quantum chemical calculations predict the possibility of OH and NH tautomeric forms.