Hydrochloric Acid → (2-Bromo-6-fluorophenyl)hydrazine hydrochloride

2-Bromo-6-fluoroaniline (2.0 g, 11 mmol) was dissolved in hydrochloric acid (7.0 mL, 12 N aqueous, 84 mmol, 8 equiv) and cooled to 0° C. An aqueous solution (10 mL) of sodium nitrite (0.80 g, 12 mmol, 1.1 equiv) was added dropwise over 30 minutes via additional funnel and the mixture was stirred for an additional 30 minutes at 0° C. A hydrochloric acid solution (10 mL, 12 N aqueous) of stannous(II) chloride dihydrate (7.1 g, 32 mmol, 3 equiv) was then added to the mixture over 45 minutes via additional funnel and the mixture was stirred for an additional 1 hour at 0° C. To the mixture, sodium hydroxide (30 mL, 1 M aqueous) was added slowly until basic by pH paper. The mixture was warmed to ambient temperature, poured into sodium hydroxide (50 mL, 25% aqueous) and the aqueous layer was extracted with diethyl ether (3×250 mL). The combined organic extracts were dried with sodium sulfate, filtered and partially concentrated in vacuo. The residue was taken up in diethyl ether and treated with gaseous hydrochloric acid. The solid was filtered and washed with diethyl ether, providing the titled compound as a white solid.