Pyridine-2-carbaldehyde, also called 2-formylpyridine, is an organic compound with the formula NC5H4CHO. It is one of three isomeric pyridinaldehydes. The other isomers are pyridine-3-carboxaldehyde and pyridine-4-carboxaldehyde. Pyridine-2-carbaldehyde is a colorless oily liquid with a distinctive odor. Older samples are often brown-colored owing to impurities. It serves as a precursor to other compounds of interest in coordination chemistry and pharmaceuticals. Pyridine aldehydes are typically prepared by oxidation of the hydroxymethyl- or methylpyridines. Reactions and uses The drug pralidoxime can be produced from 2-formylpyridine. The aldehyde functional group is subject to nucleophilic attack, specifically by amines to form Schiff bases, which serve as bidentate ligands. Iminopyridine complexes can be remarkably robust. References Aromatic aldehydes 2-Pyridyl compounds