Synthesis
5-Fluoro-2-methylbenzo[d]thiazole (1 g, 5.98 mmol) was used as starting material and dissolved in ethylene glycol (5 mL). To this solution was added 8N NaOH aqueous solution (5 mL). The reaction mixture was stirred at 140°C for 3 h. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was cooled to room temperature and the pH was adjusted to 6 with 1N HCl aqueous solution, followed by extraction with dichloromethane (DCM). The organic phases were combined, dried with anhydrous Na2SO4, filtered, and the solvent was concentrated under reduced pressure to give 2-amino-4-fluorophenyl mercaptan as a brown oil (0.8 g, 94.1% yield). The product was analyzed by liquid chromatography-mass spectrometry (LCMS): [M + 1] = 192.90; retention time (R) was 2.80 min.
References
[1] Patent: WO2016/197078, 2016, A1. Location in patent: Paragraph 284; 285-286; 311; 318-319; 702-703; 725-726; 997
[2] Journal of Medicinal Chemistry, 2005, vol. 48, # 9, p. 3141 - 3152
[3] Journal of Medicinal Chemistry, 2002, vol. 45, # 11, p. 2229 - 2239
[4] Bioorganic and Medicinal Chemistry, 2012, vol. 20, # 2, p. 866 - 876
