General procedure for the synthesis of 4-benzyloxyphenylhydrazine hydrochloride from 4-benzyloxyaniline hydrochloride: (4-(benzyloxy)phenyl)hydrazine hydrochloride (2). Note: Keep the reaction mixture and all added solutions at 0°C during this procedure. Add 4-(benzyloxy)aniline hydrochloride (3.00 g, 12.5 mmol) and water (25 mL) to the reaction flask and stir for 10 minutes at 0°C. Subsequently, a solution of NaNO2 (852 mg, 12.3 mmol) in water (6 mL) was slowly added dropwise over 15 minutes. After the dropwise addition, stirring of the reaction mixture was continued for 15 min. Then, a solution of SnCl2 (6.40 g, 33.1 mmol) in water (7.5 mL) was slowly added. After addition, the reaction mixture was stirred at 0°C for 1 hour. After completion of the reaction, the off-white precipitate was collected by filtration, washed with water and ground with ether (Et2O) to afford the target product 2 (3.01 g, 96% yield). The product characterization data were as follows: IR (ATR, pure) νmax 3232, 2906 (br), 2693, 1568, 1508, 1242, 1177 cm-1; 1H NMR (DMSO-d6, 600 MHz) δ 10.11 (bs, 3H), 7.44-7.40 (m, 2H), 7.40-7.35 (m, 2H ), 7.33-7.29 (m, 1H), 7.01-6.93 (m, 4H), 5.05 (s, 2H); 13C NMR (DMSO-d6, 150MHz) δ 153.7, 139.1, 137.3, 128.5, 128.4, 128.3, 127.9, 127.7, 127.5, 117.1, 116.9, 115.5, 116.9, 115.5, 116.9, 116.9, 115.5, 117.1 116.9, 115.5, 115.3, 69.5; HRMS (EI) m/z calculated value C13H14N2 214.1106, measured value 214.1110.
