pyridine4carboxylic

Pyridine-4-carboxylic acid, also known as isonicotinic acid, is an organic compound with the chemical formula C6H5NO2. It is a derivative of pyridine, a heterocyclic aromatic organic compound, with a carboxylic acid group attached at the 4-position of the pyridine ring. Isonicotinic acid is a white crystalline solid that is soluble in water and ethanol.

This compound is an important precursor in the synthesis of various pharmaceuticals, most notably isoniazid, a primary drug used in the prevention and treatment of tuberculosis. It also finds applications in the development of other medicinal agents and as a ligand in coordination chemistry due to the presence of both a nitrogen atom and a carboxylic acid group, which can bind to metal ions.

Isonicotinic acid can be synthesized through the oxidation of 4-methylpyridine (gamma-picoline). Its properties and reactivity are characteristic of both pyridine and carboxylic acids. It is a weak acid. The pyridine ring imparts aromatic stability, while the carboxylic acid group allows for reactions such as esterification and salt formation. The compound is also a key intermediate in the production of certain agrochemicals and specialty chemicals.