Synthesis
General procedure for the synthesis of 2-chloro-3-methoxyaniline from 2-chloro-3-nitroanisole: 2-chloro-3-nitroanisole (1.38 g, 7.36 mmol) was dissolved in a solvent mixture of glacial acetic acid (19 mL) and acetonitrile (19 mL). To this solution was added iron powder (1.64 g, 29.4 mmol). The reaction mixture was stirred under reflux conditions for 3.5 hours. After completion of the reaction, the mixture was diluted with water (70 mL) and neutralized with solid sodium carbonate (Na2CO3). Subsequently, the product was extracted with dichloromethane (3 x 150 mL). The organic phases were combined, washed with saturated saline, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure to afford the crude product 2-chloro-3-methoxyaniline (1.2 g, 100% yield) as a yellow oil. The product was used directly in the next reaction without further purification. Mass spectrometry (MS) analysis showed a molecular ion peak of 157.9 (MH)+; high performance liquid chromatography (HPLC, with TFA as additive) showed a purity of 86% at 220 nm.
References
[1] Patent: WO2004/103996, 2004, A1. Location in patent: Page 42-43
[2] Patent: WO2006/7700, 2006, A1. Location in patent: Page/Page column 62
[3] Patent: US2006/19905, 2006, A1. Location in patent: Page/Page column 25
[4] Patent: WO2006/85, 2006, A1. Location in patent: Page/Page column 77-78
[5] Chemistry - A European Journal, 2017, vol. 23, # 42, p. 9996 - 10000
