This pungent liquid is a building block for the synthesis of other heterocyclic compounds.

Its conjugate acid, the 4-methylpyridinium ion, has a pKa of 5.98, about 0.7 units above that of pyridine itself.

It forms via the reaction of acetaldehyde and ammonia in the presence of an oxide catalyst.

4-Methylpyridine is of little intrinsic value but is a precursor to other commercially significant species, often of medicinal interest.

For example, ammoxidation of 4-methylpyridine gives 4-cyanopyridine, the precursor to a variety of other derivatives such as the antituberculosis drug isoniazid.