Synthesis and structure of Two thiocarboxypyrazolic Acid Derivatives

Two thiocarboxypyrazolic acid amide derivatives were obtained unintentionally in a reaction of thiosemicarbazone with 2-acetylbutyrolactone, and structures of the final products have been determined by X-ray diffraction. Due to conjugation of the thioamide group with the planar pyrazolic ring, the molecule is flat, except 2-hydroxylethyl chain, accidentally adopting similar conformation in the two studied molecules. Also similar is the packing, despite different hydrogen bonding schemes, resulting from the different number of donoric H atoms and the presence of an additional water molecule in the second compound. The mechanism of the reaction is suggested.