Synthesis
General procedure for the synthesis of 6-fluoro-2-hydrazinylbenzothiazole (2) from 2-amino-6-fluorobenzothiazole: Concentrated hydrochloric acid (10 mL) was slowly added dropwise to 99% hydrazine hydrate (10 g, 0.2 mol) at 5-10 °C, followed by the addition of 2-amino-6-fluorobenzothiazole (1) (3.364 g, 0.02 mol) to a glycol (40 mL) solution. The reaction mixture was heated to reflux temperature and kept for 5 hours. After completion of the reaction, it was cooled to room temperature, the precipitated solid product was collected by filtration, washed with water, dried and purified by recrystallization from ethanol. The product yield was 89% and the melting point was 194-196°C [1].
References
[1] Journal of Heterocyclic Chemistry, 2014, vol. 51, # 2, p. 459 - 465
[2] Chinese Chemical Letters, 2015, vol. 26, # 12, p. 1522 - 1528
[3] Bioorganic and Medicinal Chemistry Letters, 2007, vol. 17, # 14, p. 4022 - 4025
[4] Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1981, vol. 20, # 4, p. 314 - 316
[5] European Journal of Medicinal Chemistry, 2010, vol. 45, # 9, p. 4293 - 4299
