Synthesis
b) Synthesis of methyl 4-amino-3-trifluoromethyl-benzoate: 4.0 g (16.1 mmol) of methyl 4-nitro-3-trifluoromethyl-benzoate was dissolved in 50 mL of methanol and 0.4 g of 10% palladium carbon catalyst was added. The reaction mixture was stirred at room temperature and under hydrogen atmosphere (1.7 bar) for 2 hours. Upon completion of the reaction, the catalyst was diluted by adding 100 mL of ethyl acetate and filtered to remove the catalyst. The filtrate was concentrated and dried under high vacuum to afford methyl 3-trifluoromethyl-4-aminobenzoate as a white solid in 98% yield. The product did not need further purification and could be used directly in the subsequent reaction.
References
[1] Patent: US2009/163552, 2009, A1. Location in patent: Page/Page column 31
[2] Patent: EP2017263, 2009, A1. Location in patent: Page/Page column 248
[3] Patent: US2010/185419, 2010, A1
[4] Patent: WO2016/55947, 2016, A1. Location in patent: Page/Page column 61; 68
