2,6-Lutidine
2,6-Lutidine is a natural heterocyclic aromatic organic compound with the formula 2C5H3N. It is one of several dimethyl-substituted derivative of pyridine, all of which are referred to as lutidines. It is a colorless liquid with mildly basic properties and a pungent, noxious odor.
Occurrence and production
It was first isolated from the basic fraction of coal tar and from bone oil.A laboratory route involves condensation of ethyl acetoacetate, formaldehyde, and an ammonia source to give a bis of a 2,6-dimethyl-1,4-dihydropyridine, which, after hydrolysis, undergoes decarboxylation.
It is produced industrially by the reaction of formaldehyde, acetone, and ammonia.
Uses
2,6-Lutidine has been evaluated for use as a food additive owing to its nutty aroma when present in solution at very low concentrations.Due to the steric effects of the two methyl groups, 2,6-lutidine is less nucleophilic than pyridine. Protonation of lutidine gives lutidinium, +, salts of which are sometimes used as a weak acid because the conjugate base is so weakly coordinating. In a similar implementation, 2,6-lutidine is thus sometimes used in organic synthesis as a sterically hindered mild base.
One of the most common uses for 2,6-lutidine is as a non-nucleophilic base in organic synthesis. It takes part in the formation of silyl ethers as shown in multiple studies.
Oxidation of 2,6-lutidine with air gives 2,6-diformylpyridine:
2,6-Lutidine also finds application in the synthesis of Nifurpirinol .