3-Aminophenol → 3-Hydrazinylphenol

To a stirred, ice cooled solution of 3-aminophenol (2.00 g, 18.3 mmol) in concentrated HCl (20 mL) was added dropwise a solution of sodium nitrite (1.33 g, 19.24 mmol) in H2O (10 mL), ensuring the internal temperature did not exceed 10° C. After 10 min, a solution of tin (II) chloride (7.645 g, 40.3 mmol) in concentrated HCl (10 mL) was added dropwise, and the ice bath removed. After stirring at RT for 45 min, the reaction was basified to pH 10 with careful addition of 10 M NaOH solution (50 mL), and then extracted with EtOAc (3×). The organic extracts were dried over MgSO4, concentrated in vacuo and triturated with Et2O to afford the title compound as a brown solid (353 mg, 16%). 1H NMR (300 MHz, d6-DMSO): 3.83 (2H, br s), 5.96-6.02 (1H, m), 6.15-6.21 (1H, m), 6.22 (1H, t, J=2.2 Hz), 6.52 (1H, br s), 6.84 (1H, t, J=8.0 Hz), 8.91 (1H, br s).