chloropyridine
Chloropyridines are a group of aryl chlorides consisting of a pyridine ring with chlorine atoms as substituents.
Chloropyridines include:
Production
File:Pyridinols_to_chloropyridines.svgDirect halogenation of pyridine with chlorine gas above 270 °C gives a mixture of 2-chloropyridine and 2,6-dichloropyridine.
2- and 4-chloropyridine are prepared from the corresponding pyridinols using phosphoryl chloride.
Uses
Chloropyridines are important intermediates to pharmaceuticals and agrochemicals.{{Ullmann|first1=Günter |last1=Siegemund|first2=Werner|last2=Schwertfeger|first3=Andrew|last3=Feiring|first4=Bruce|last4=Smart|first5=Fred|last5=Behr|first6=Herward|last6=Vogel|first7=Blaine |last7=McKusick|title=Pyridine and Pyridine Derivatives|year=2000|doi=10.1002/14356007.a22_399}} 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.