General procedure for the synthesis of 2-chloro-7-nitrobenzo[d]thiazole from 2-amino-7-nitrobenzothiazole: 0.195 g (1.0 mmol) of 7-nitro-1,3-benzothiazol-2-amine and 0.336 g (2.5 mmol) of copper chloride were dissolved in 2 mL of N,N-dimethylformamide (DMF), followed by the slow dropwise addition of 0.15 mL ( 1.25 mmol) tert-butyl nitrite. The reaction mixture was stirred at room temperature for 24 hours. Upon completion of the reaction, the mixture was poured into water and the resulting precipitate was collected by filtration and dried to give 0.163 g (76% yield) of the target compound 2-chloro-7-nitrobenzo[d]thiazole as a tan powder. Calculated mass spectrum value (MS Calcd.): 215; measured value (MS Found): 214 (M-H).
