Stannous Chloride → 4-Chloro-3-hydrazinylphenol hydrochloride

Participants

Reaction Steps

A solution of sodium nitrite (2.07 g, 30.0 mmol) in water (6.0 mL) was added dropwise to an ice cold slurry of 3-amino-4-chlorophenol (4.30 g, 30.0 mmol) and hydrochloric acid (37% aqueous, 9.0 mL) and the mixture stirred for 45 min. Tin (II) chloride (15.4 g, 81.0 mmol) in water (18.0 mL) and hydrochloric acid (37% aqueous, 18.0 mL) was added dropwise and the reaction stirred overnight. The mixture was cooled in an ice/water bath, diluted with water and neutralised by addition of NaOH (1M aq). The aqueous layer was then extracted with EtOAc (3×). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The residue was passed through an acidic ion-exchange cartridge (SCX-2), washing with methanol and eluting with 2M ammonia in methanol. The basic fraction was evaporated in vacuo then purified by FCC, using 3-10% [2M NH3 in MeOH] in DCM, to give the title compound (1.30 g, 27%). 1H NMR (300 MHz, d6-DMSO): 4.12 (2H, br s), 6.03 (1H, dd, J=8.5, 2.9 Hz), 6.26 (1H, s), 6.63 (1H, d, J=2.7 Hz), 6.93 (1H, d, J=8.5 Hz), 9.22 (1H, s).

Provenance & Evidence