General procedure for the synthesis of (5-bromothiophen-2-yl)methylamine hydrochloride from tert-butyl (5-bromothiophen-2-yl)methylcarbamate: tert-butyl (5-bromothiophen-2-yl)methylcarbamate (8.322 g, 0.0285 mmol) was dissolved in 150 mL of anhydrous ethyl acetate. After continuous passage of dry HCl gas for 2 h, a large amount of precipitate generation was observed. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The resulting residue was washed sequentially with anhydrous ethyl acetate (3 x 50 mL) and ether (3 x 50 mL) to give the final target product (5-bromothiophen-2-yl)methylamine hydrochloride (5.862 g) in 95% yield.