Synthesis, Structural Characterization, in Silico ADME Approach and Thermal Analysis of (Z)-2-(5-bromo-2-oxoindolin-3-ylidene)-N-R-Hydrazinecarbothioamide

Two thiosemicarbazone derivatives, named (Z)-2-(5-bromo-2-oxoindolin-3-ylidene)-N-methyl-hydrazinecarbothiamide (1) and (E)-2-(5-bromo-2-oxoindolin-3-ylidene)-N-phenyl-hydrazinecarbothiamide (2), are synthesized by the reaction between bromoisatin and the corresponding thiosemicarbazides (methyl or phenyl) under acid catalysis. The reactions are carried out under reflux, leading to products with analytical purity and yields of 85.44% (1) and 84.73% (2). Both compounds are characterized by FTIR, 1H and 13C{1H} NMR spectroscopy, and thermal analysis (TGA-DTA). The TGA-DTA results revealed high thermal stability up to approximately 260 °C, with decomposition occurring in three main steps influenced by the substituent group. Additionally, compound 1 is characterized by single crystal X-ray diffraction. Spectroscopic data confirm the expected functional groups and structural features, supporting the successful synthesis and structural elucidation of two bromoisatin-derived thiosemicarbazones.