Synthesis of oxindole Substituted imidazothiadiazole

In this experiment a mixture of 4-Chlorophenyl acetic acid (1 eq) and thiosemicarbazide (1.5 eq) was added slowly to the round bottom flask containing concentrated H2SO4 with constant stirring in ice bath. After complete addition, ice bath was replaced by water bath and slowly heated to 70-80 ⁰C and maintained at that temperature for 7 hrs. After cooling to room temperature, the contents of the reaction were poured into ice water and made basic with ammonia and the precipitate was filtered, washed with water and recrystallized from ethanol. All work relating to analytical thin layer chromatography were performed with silica gel 60F254 aluminum plates and were visualized with UV light. Melting points were recorded on a Thomas Hoover capillary melting point apparatus and are uncorrected.  The following mobile phases were employed for TLC : hexane and ethyl acetate in different ratios. The instrumental techniques employed for the characterization of the newly synthesized compounds include 1H and 13C NMR spectroscopy. 1H and 13C NMR spectra were recorded on a (400 and 300 MHz)