Chloropyridine

Chloropyridines are a group of aryl chlorides consisting of a pyridine ring with chlorine atoms as substituents.

Chloropyridines include:

• 2-Chloropyridine
• 3-Chloropyridine
• 4-Chloropyridine
• 2,6-Dichloropyridine

Production

Production of chloropyridines from pyridinols

Direct halogenation of pyridine with chlorine gas above 270 °C gives a mixture of 2-chloropyridine and 2,6-dichloropyridine.[1]

2- and 4-chloropyridine are prepared from the corresponding pyridinols using phosphoryl chloride.[1]

Uses

Chloropyridines are important intermediates to pharmaceuticals and agrochemicals.[1] A major use of 2-chloropyridine is the production of production of the fungicide pyrithione. Reaction of 4-chloropyridine with thioglycolic acid gives pyridylmercaptoacetic acid, a step in the production of cephalosporin antibiotics.

See also

• Bromopyridine

References

1. Siegemund, Günter; Schwertfeger, Werner; Feiring, Andrew; Smart, Bruce; Behr, Fred; Vogel, Herward; McKusick, Blaine (2000). "Pyridine and Pyridine Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_399. ISBN 978-3-527-30673-2.