Synthesis
General procedure for the synthesis of 4-(trifluoromethoxy)benzene-1,2-diamine from 2-nitro-4-trifluoromethoxyaniline: a solution of 2-nitro-4-trifluoromethoxyaniline (25.0 g, 0.112 mol) in ethanol (200 mL) was slowly added to a solution of concentrated hydrochloric acid (330 mL) of tin chloride dihydrate (82.0 g, 0.363 mol). The reaction mixture was stirred at 70-80°C for 0.5 hours. Upon completion of the reaction, the mixture was cooled to 0-5°C and the pH was adjusted to 11-12 with 40% sodium hydroxide solution.Subsequently, the reaction product was extracted with ether (2 x 200 mL). The organic phases were combined, washed with water and dried over anhydrous sodium sulfate. Finally, the solvent was removed by evaporation under reduced pressure to give 4-(trifluoromethoxy)benzene-1,2-diamine as a brown oil (21.1 g, 98% yield).
References
[1] Patent: WO2006/50148, 2006, A2. Location in patent: Page/Page column 38
[2] Patent: WO2008/75109, 2008, A1. Location in patent: Page/Page column 160
[3] Patent: WO2006/130673, 2006, A1. Location in patent: Page/Page column 115
[4] Patent: WO2006/22954, 2006, A2. Location in patent: Page/Page column 24
[5] Patent: US2014/315963, 2014, A1. Location in patent: Paragraph 0228
