General procedure for the synthesis of 3,5-dimethoxyphenylacetonitrile from trimethylsilyl cyanide and 3,5-dimethoxybenzyl bromide: In 100 mL of acetonitrile, 2.310 g (0.01 mol) of 3,5-dimethoxy-4-bromobenzyl bromide, 1.485 g (0.015 mol) of trimethylsilyl cyanide, and 4.725 g (0.015 mol) of tetra butylammonium fluoride in a 30 mL three-neck flask. The mixture was stirred and heated to reflux and the reaction was carried out for 6 hours, during which time the progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, it was cooled to room temperature and the reaction solution was poured into 100 mL of ice water and stirred until a white solid precipitated. The solid was collected by filtration, washed with 50% methanol and dried to afford the target compound 3,5-dimethoxyphenylacetonitrile in 66.7% yield.
