Synthesis
General procedure for the synthesis of 3-methyl-2-nitroaniline from 3-methyl-2-nitrobenzamide: NaOH (2.220 g, 55.5 mmol) was dissolved in water (12 mL) at 0°C, followed by the addition of Br2 (0.322 mL, 6.26 mmol). Next, 3-methyl-2-nitrobenzamide (1 g, 5.55 mmol) was added all at once and the mixture was slowly heated in a water bath to 50-55°C (internal temperature), at which point oil droplets were observed to separate. The temperature was continued to be gradually increased to 70°C and maintained at this temperature for 1 hour. Subsequently, a solution of NaOH (0.7 g) dissolved in water (4 mL) was added and the temperature was slowly raised to 80°C and held for another 1 hour. After completion of the reaction, it was cooled to room temperature and extracted with EtOAc (3x50mL). The organic layers were combined, dried and concentrated to give 0.7 g (90% yield) of the target compound 3-methyl-2-nitroaniline.LC-MS analysis showed m/z of 153.1 (M + H)+ and retention time of 1.65 min.
References
[1] Patent: WO2015/92713, 2015, A1. Location in patent: Page/Page column 73; 74
[2] Patent: WO2016/203400, 2016, A1. Location in patent: Page/Page column 49
[3] Patent: WO2016/203401, 2016, A1. Location in patent: Page/Page column 60; 61
[4] Patent: WO2016/202253, 2016, A1. Location in patent: Page/Page column 126; 127
[5] Patent: WO2018/104766, 2018, A1. Location in patent: Page/Page column 60-61
