Synthesis
General procedure for the synthesis of 1-bromo-2-methyl-3,4-dinitrobenzene from 2-bromo-6-nitrotoluene:
Step 1: 2-Bromo-6-nitrotoluene (43.2 g, 0.2 mol) was dissolved in sulfuric acid (600 mL) at 0°C and nitric acid (37 g, 0.24 mol) was added in batches. Effective stirring was maintained during the reaction and the temperature was controlled between 0 and 10°C. The reaction mixture was slowly warmed to room temperature and stirring was continued overnight. Subsequently, the reaction mixture was quenched by pouring it into crushed ice (1600 g). The resulting solid product was collected by filtration, washed well with water and dried in air. The crude product was purified by solvent recrystallization from ethyl acetate/hexane mixture to give 40 g (11% yield) of 1-bromo-2-methyl-3,4-dinitrobenzene (154) as a light white solid. Mass spectrum (ESI) m/z = 262 [M+1]+.
References
[1] Tetrahedron Letters, 2000, vol. 41, # 22, p. 4277 - 4279
[2] Patent: WO2013/26914, 2013, A1. Location in patent: Page/Page column 142
[3] Patent: WO2009/134850, 2009, A1. Location in patent: Page/Page column 29-30
[4] Patent: WO2010/45166, 2010, A1. Location in patent: Page/Page column 57-58
[5] Patent: US2010/222345, 2010, A1. Location in patent: Page/Page column 87
