Synthesis
The general procedure for the synthesis of 2,4-dimethyl-m-dibromobenzene from m-xylene was as follows: 7.5 mmol (0.795 g) of m-xylene, 33.6 mmol (7.56 g) of zinc bromide, and 60 mL of nitromethane were added to a 200 mL aubergine flask. The resulting solution was stirred at room temperature, followed by the slow addition of 15.8 mmol (6.19 g) di-n-butyltetrabutylammonium in batches. The reaction mixture was stirred continuously for 44 hours at room temperature before the reaction was quenched by the addition of aqueous sodium sulfite and extracted with ether. The organic layers were combined and concentrated under reduced pressure to give a yellow solid. Hexane was added to the yellow solid and the mixture was heated to about 85°C and filtered. The filtrate was concentrated under reduced pressure to give 0.945 g of white solid, the target product 2,4-dimethyl m-dibromobenzene (yield: 48%).
References
[1] Tetrahedron, 2016, vol. 72, # 41, p. 6363 - 6367
[2] Chemistry - A European Journal, 2013, vol. 19, # 32, p. 10672 - 10689
[3] Journal of Organic Chemistry, 2005, vol. 70, # 21, p. 8522 - 8526
[4] Patent: EP1816134, 2007, A1. Location in patent: Page/Page column 32; 33
[5] Patent: JP2016/47836, 2016, A. Location in patent: Paragraph 0051-0052
