7.7 g of a 47% w/v aqueous solution of hydrobromic acid and a solution of 1.3 g of sodium nitrite in 3 ml of water were added dropwise, in that order, to a solution of 4.3 g of 4-(2,5-dimethoxy-3,4,6-trimethylphenoxy)aniline [prepared as described in step (c) above] in 10 ml of acetone, after which 21 ml of butyl acrylate were added to the mixture. After that, 0.3 g of cupric bromide was gradually added and the resulting mixture was stirred at room temperature for 4 hours. At the end of this time, the reaction mixture was poured into water, after which it was extracted with benzene. The extract was washed with water and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure from the extract, and the residue thus obtained was purified by column chromatography through silica gel, using a 3:7 by volume mixture of hexane and benzene as the eluent, to give 5.7 g of the title compound.
