The general procedure for the synthesis of 2(3H)-5-bromobenzothiazolone from tritiated gas and 2-amino-4-bromobenzenethiol was as follows: 2-amino-4-bromobenzenethiol (544 mg, 2.67 mmol) was dissolved in acetic acid (26.7 mL), followed by the addition of tritiated gas (530 mg, 1.79 mmol). The reaction mixture was heated to reflux for 18 hours. Upon completion of the reaction, it was cooled to room temperature, some of the solvent was concentrated under reduced pressure, water was added, and the precipitate was collected by filtration and washed with 1.0 M NaOH aqueous solution. The filtrate was acidified to pH 2 with 2 N HCl and then placed in a refrigerator for 12 hours. The precipitate was precipitated by filtration, washed with water and dried under reduced pressure to give 2(3H)-5-bromobenzothiazolone (94 mg, 15% yield) as a powder to be further purified. The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 12.07 (s, 1H), 7.55 (d, J = 8.4 Hz, 1H), 7.30 (d, J = 8.0 Hz, 1H), 7.24 (s, 1H).
