Synthesis
General procedure for the synthesis of 2-methyl-3-bromo-5-fluoroaniline from 2-bromo-4-fluoro-6-nitrotoluene: [00402] Ammonium chloride (571 mg, 10.7 mmol) was added to a mixture of 1-bromo-5-fluoro-2-methyl-3-nitrobenzene (500 mg, 2.14 mmol) and iron powder (0.6 g, 10.68 mmol). Water (24 mL) and ethanol (24 mL) were subsequently added. The reaction mixture was refluxed for 5 h. After completion of the reaction, it was filtered through diatomaceous earth and the filter cake was washed with ethanol (100 mL) and ethyl acetate (100 mL). The organic solvent was removed in vacuum to give an aqueous solution, which was extracted with dichloromethane (3 x 30 mL). The organic layer was separated and concentrated to afford the crude product 3-bromo-5-fluoro-2-methylaniline (390 mg, 1.87 mmol, 87.7% yield), which was analyzed by nuclear magnetic resonance (NMR) and showed good purity and could be used in the next reaction without further purification. [00403] 1H NMR (DMSO-d6): δ 6.60 (dd, J = 2.8 and 8.4 Hz, 1H), 6.42 (dd, J = 2.8 and 11.6 Hz, 1H), 5.54 (bs, 2H), 2.09 (s, 3H).
References
[1] Organic Letters, 2017, vol. 19, # 24, p. 6518 - 6521
[2] Green Chemistry, 2018, vol. 20, # 1, p. 130 - 135
[3] Patent: WO2015/79251, 2015, A1. Location in patent: Paragraph 00402; 00403
[4] Patent: WO2011/130628, 2011, A1. Location in patent: Page/Page column 155
[5] Patent: US2013/102595, 2013, A1. Location in patent: Paragraph 0279; 0280
