2,4,6-Trimethylpyridine Explained

2,4,6-Trimethylpyridine (2,4,6-collidine) is an organic compound which belongs to the heterocycles (more precisely, heteroaromatics). It consists of a pyridine ring substituted with three methyl groups. It belongs to the substance group of the collidines, a group of six constitutional isomers. 2,4,6-trimethylpyridine is the most well-known isomer of this group.

Properties

The compound has a refractive index of 1.4959 (25 °C).^[1]

Preparation

2,4,6-Trimethylpyridine was isolated from Dippel's oil in 1854.^{[2] [3]} A synthesis can be carried out analogously to the Hantzsch's dihydropyridine synthesis from ethyl acetoacetate (as β-ketocarbonyl compound), acetaldehyde and ammonia in the ratio 2: 1: 1.^[4]

Use

By oxidation of the methyl groups with potassium permanganate collidinic acid is obtained.

2,4,6-Trimethylpyridine is used in organic syntheses (for example, for dehydrohalogenation), by binding the formed hydrogen halides.

See also

• 2,6-Dimethylpyridine (lutidine)

References

1. Book: David R. Lide. CRC Handbook of Chemistry and Physics. 90th. (Internet-Version: 2010). CRC Press/Taylor and Francis. Boca Raton, FL. Physical Constants of Organic Compounds. 3–510.
2. Collidin. In: Heinrich August Pierer, Julius Löbe (Hrsg.): Universal-Lexikon der Gegenwart und Vergangenheit. 4. Auflage. Band 4. Altenburg 1858, S. 262 (zeno.org).
3. Friedrich Auerbach: „Ueber ein neues Collidin“, in: Berichte der deutschen chemischen Gesellschaft, 1892, 25 (2), S. 3485–3490 .
4. T. Laue, A. Plagens: Namen- und Schlagwort-Reaktionen der Organischen Chemie, 5. Auflage, Teubner Verlag, Wiesbaden 2006,, S. 172.