Subsequently, 12 M hydrochloric acid (4 equiv.) and zinc dust (2.5 equiv.) were slowly added to the solution and let to stir at rt for 15 min. To the resulting slurry, a solution of ammonia (30%, 14 mL) and sodium hydroxide (6 M, 30 mL) was added dropwise and the mixture was stirred at rt for another 15 min. Then, the resulting solution was extracted with DCM, dried over anhydrous Na2SO4, and filtered. The solvent was removed under vacuum to give the amines without further purification.