Hydroxylamine HCl → 2-Chloro-3-hydroxybenzonitrile

A mixture of 2-chloro-3-hydroxybenzaldehyde [(2 g, 12.8 mmol) WO 2005007633, p 34] and hydroxylammonium chloride (1.33 g, 19.6 mmol) in acetic acid (20 mL) was heated under reflux for 2 hours. The reaction mixture was then cooled to room temperature and partitioned between diethyl ether and water. The organic layer was separated, washed with brine, dried over magnesium sulfate and concentrated in vacuo to give a white solid. The solid was then dissolved in ethyl acetate washed with water and brine, dried over magnesium sulfate and concentrated in vacuo to afford the title compound as a solid in quantitative yield.