2933-29-1

108-94-1

17356-08-0

2933-29-1

GENERAL METHODS: A mixture of cyclohexanone (2 mmol), thiourea (3 mmol) and iodine (2 mmol) was reacted by refluxing in ethanol in the presence of 0.03 g of nano-chitosan catalyst. The progress of the reaction was monitored by thin layer chromatography (TLC, unfolding agent was petroleum ether to ethyl acetate in 4:1 volume ratio). Upon completion of the reaction, the catalyst was removed by simple filtration. After evaporation to remove the solvent, the crude product was dissolved in boiling water and extracted with ether (3 x 30 mL). Subsequently, the pH of the aqueous phase was adjusted to 8 with ammonia to precipitate the solid product. Finally, pure 2-amino-4,5,6,7-tetrahydrobenzothiazole was obtained by recrystallization from ethanol-water mixed solvent.