2-Chloronicotinic acid (2-CNA) is a halogenated derivative of nicotinic acid that is used as an intermediate in the production of a variety of bioactive compounds, including boscalid and diflufenican. It can be synthesized by chlorination of the N-oxide of nicotinic acid or related nicotinyl compounds, by substitution of the hydroxyl group of 2-hydroxynicotinic acid, or by a tandem reaction involving cyclization of various acrolein derivatives.