Synthesis
The synthesis of 5-bromo-2-chlorobenzylamine (3) as the target was carried out as follows: azide 2 (2.4 g, 9.76 mmol) was dissolved in THF (60 mL) at 0 °C, and triphenylphosphine (2.86 g, 10.90 mmol, 1.12 eq.) was slowly added while stirring. After addition, the mixture was continued to stir at 0 °C for 10 min, followed by overnight stirring at room temperature. Complete consumption of the raw material was confirmed by TLC analysis (unfolding agent: EtOAc-hexane, 1:20). Subsequently, ammonium hydroxide solution (10 mL) was added drop-wise and after stirring for 30 minutes, 1N NaOH solution (20 mL) was added and the resulting mixture was continued to be stirred for 2 hours at room temperature. After the reaction was completed, it was diluted by adding ether (100 mL) and water (80 mL). The mixture was adjusted to acidity (pH 2) by slowly adding 4N H2SO4 solution dropwise. The aqueous layer was separated and adjusted to basicity with 4N NaOH solution, followed by extraction with DCM (2 x 100mL). The organic layers were combined, dried with MgSO4 and concentrated under reduced pressure. The residue was purified by column chromatography (eluent: MeOH-DCM, 1:20) to afford the target product 3 as a colorless liquid (1.45 g, 67% yield). The product was analyzed by LC-MS showing: retention time (R t) 3.67 min, mass-to-charge ratio (m/e) 221.1,205.1; 1H NMR (CDCl3) δ 7.64 (s, 1H), 7.40 (dd, 1H), 7.28 (d, 1H), 4.02 (s, 2H), 1.58 (s, broad peak, 2H, NH2).
