Synthesis
The general procedure for synthesizing 2-bromo-4,5-dimethylaniline from 1-bromo-4,5-dimethyl-2-nitrobenzene is as follows:[Ref. Example 32] 1.006 g (4.375 mmol) of 1-bromo-4,5-dimethyl-2-nitrobenzene was placed in a 100 mL round-bottomed flask fitted with a magnetic stirrer, and 1 mL of 2-methoxyethanol and 10 mL of water were added and stirred to A suspension was formed. To the suspension was added 2.799 g (10.07 mmol) of sodium dithionite, which was heated under vigorous stirring in an oil bath at 100 °C. After 2.5 h, 10 mL of water was added to the reaction system, and heating and stirring was continued until the insoluble material was completely dissolved, yielding a pale yellow solution. To this solution 10 mL of concentrated hydrochloric acid was added slowly and dropwise over a period of 5 min, followed by refluxing the mixture for 20 min. After completion of the reaction, the mixture was cooled to room temperature and neutralized with sodium carbonate powder to pH 7-8, at which point a light brownish white precipitate precipitated. The precipitate was collected and dried to give the target product 2-bromo-4,5-dimethylaniline as a white solid. Yield: 0.832 g (95.0% yield).1H-NMR (270 MHz, CDCl3) δ: 2.13 (6H, s), 6.59 (1H, s), 7.16 (1H, s).
References
[1] Patent: EP1505067, 2005, A1. Location in patent: Page/Page column 379
[2] Patent: EP1502916, 2005, A1. Location in patent: Page 463-464
