Hydroxyamine hydrochloride → 2-Chloro-6-fluoro-4-hydroxybenzonitrile

A solution of 2-chloro-6-fluoro-4-hydroxybenzaldehyde (WO 2008141249, 90 mg, 0.344 mmol) in formic acid (1 mL) was treated with hydroxylamine hydrochloride (23.9 mg, 0.344 mmol) and sodium formate (23.4 mg, 0.344 mmol) and stirred under nitrogen for 3.5 hours at 105° C. The mixture was concentrated in vacuo and the residue treated with saturated aqueous sodium bicarbonate solution (10 mL). The aqueous solution was extracted with ethyl acetate (2×10 mL), dried over sodium sulphate and concentrated in vacuo. The residue was purified using silica gel column chromatography eluting with 30-50% EtOAc in heptanes to afford the title compound as a beige solid (33 mg, 56%).