Synthesis
In a reaction vessel, a concentrated phosphoric acid solution with a mass fraction of 80% and 100 mL of water were added, followed by 4-amino-3-nitroanisole (2) 0.25 mol. The stirring speed was controlled to 230 rpm and the temperature of the solution was lowered to 9 °C. A solution configured from potassium nitrite 0.25 mol dissolved in 100 mL of water was added slowly. A further 200 mL of potassium bisulfite solution with a mass fraction of 55% was added to the reaction vessel, the reaction temperature was maintained at 8 °C, and the reaction lasted for 50 min. 0.30 mol of stannous bromide was dissolved in 130 mL of concentrated potassium chloride solution, and the diazonium salt solution was rapidly added to the stannous bromide solution at 19 °C and allowed to stand for 5 hours. Subsequently, the temperature of the solution was gradually raised to 70 °C until no gas escaped. The distillate was collected by steam distillation and extracted with acetone. The extracts were combined and washed sequentially with sodium bicarbonate solution and potassium chloride solution and finally dehydrated by activated alumina. After recovery of acetone, 43.71 g of yellow solid 4-chloro-3-nitroanisole was obtained in 93% yield.
References
[1] Chemistry - A European Journal, 2017, vol. 23, # 42, p. 9996 - 10000
[2] Patent: CN104292107, 2016, B. Location in patent: Paragraph 0030; 0031
[3] Patent: CN105439868, 2016, A. Location in patent: Paragraph 0014; 0015
[4] Tetrahedron Letters, 2010, vol. 51, # 51, p. 6769 - 6771
[5] Organic Process Research and Development, 2017, vol. 21, # 1, p. 44 - 51
