Synthesis
General procedure for the synthesis of 2-amino-7-fluoro-1,3-benzothiazole from 1-fluoro-3-nitro-2-thiocyanatobenzene: 1-fluoro-3-nitro-2-thiocyanatobenzene (3.96 g, 20 mmol), ethanol (30 mL), water (25 mL) and concentrated hydrochloric acid (25 mL) were mixed and slowly heated to reflux. Subsequently, hydrogen-reduced iron powder (8 g) was added and the reaction was continued at reflux for 16 hours. Upon completion of the reaction, the reaction solution was filtered while hot and the solid residue was collected by filtration after cooling. The residue was dissolved in hot water, the pH was adjusted to neutral with ammonia, and then extracted with ethyl acetate (EtOAc). The final 7-fluorobenzo[d]thiazol-2-amine (1 g) was obtained as a colorless oil. m/z 169.2 ([M + H]+) was detected by LC-MS.
References
[1] Journal of the Chemical Society [Section] C: Organic, 1969, p. 268 - 272
[2] Patent: WO2014/139144, 2014, A1. Location in patent: Page/Page column 183; 184
[3] Patent: US2014/288081, 2014, A1. Location in patent: Paragraph 0758
[4] Patent: WO2014/139325, 2014, A1. Location in patent: Page/Page column 197
