To a solution of 150 mL of water and 45 mL of 48 % HBr add 35.8 g of 4-methyl-2-nitroaniline with stirring. Place the beaker into an ice-salt water bath and cool to 0°C, then slowly add a solution of 18 g of sodium nitrite dissolved in 45 mL of water to the mixture while maintaining the temp at 0°C. Then combine 20 g of copper(I) bromide and 27 mL of 48% HBr and pour the mixture into a reflux apparatus. Slowly start the addition of the ice-cold mixture to the copper(I) bromide, heat at 90°C for 30 minutes. Cool the solution down and extract the product with tert-butyl methyl ether, evaporate the TBME off and recrystallize from hot iPrOH.
Starting the addition of the brominating agent
A sample of the crude product
A crystal of the product