2-Chloropyridine

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2-Chloropyridine
2-chloropyridine.png
2-Chloropyridine Ball and Stick.png
2-Chloropyridine Space Fill.png
Names
Preferred IUPAC name
2-Chloropyridine
Identifiers
3D model (JSmol)
105788
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.316 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-646-3
130818
PubChem CID
RTECS number
  • US5950000
UNII
UN number 2822
  • InChI=1S/C5H4ClN/c6-5-3-1-2-4-7-5/h1-4H Yes check.svgY
    Key: OKDGRDCXVWSXDC-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C5H4ClN/c6-5-3-1-2-4-7-5/h1-4H
    Key: OKDGRDCXVWSXDC-UHFFFAOYAI
  • Clc1ncccc1
Properties
C5H4ClN
Molar mass 113.54 g/mol
Appearancecolorless liquid
Density 1.2 g/mL
Melting point −46 °C (−51 °F; 227 K)
Boiling point 166 °C (331 °F; 439 K)
27 g/L
Acidity (pKa)0.49 (for C5H4ClNH+) [1]
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H301, H310, H315, H319, H330, H400
P260, P261, P262, P264, P270, P271, P273, P280, P284, P301+P310, P301+P312, P302+P350, P302+P352, P304+P340, P305+P351+P338, P310, P311, P312, P314, P320, P321, P322, P330, P332+P313, P337+P313, P361, P362, P363, P391, P403+P233, P405, P501
Safety data sheet (SDS) MSDS
Related compounds
Related compounds
 3-Chloropyridine
3-Bromopyridine
2-Chloromethylpyridine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2-Chloropyridine is an aryl chloride with the formula C5H4ClN. It is a colorless liquid that is mainly used to generate fungicides and insecticides in industry. It also serves to generate antihistamines and antiarrythymics for pharmaceutical purposes. [2] It is one of three isomers of chloropyridine.

Contents

Preparation

Simple chlorination.png

2-Chloropyridine is produced by direct reaction of pyridine with chlorine. The initially formed 2-chloropyridine reacts further to give 2,6-dichloropyridine. [2]

Alternatively, 2-chloropyridines can be conveniently synthesized in high yields from pyridine-N-oxides. [3]

2-Chloropyridine was originally prepared by the chlorination of 2-hydroxypyridine with phosphoryl chloride. [4]

Main reactions and applications

2-Chloropyridine undergoes substitution at the C-Cl bond. [5] [6] Some reactions using 2-chloropyridine generate mixtures of products. [2]

Some commercial products include pyrithione, pyripropoxyfen, chlorphenamine, and disopyramide. In these conversions, chloride is displaced. [2] Pyrithione, the conjugate base of 2-mercaptopyridine-N-oxide, is a fungicide found in some shampoos. Oxidation 2-chloropyridine gives 2-chloropyridine-N-oxide. [7] The antihistamine pheniramine may be generated via the reaction of phenylacetonitrile with 2-chloropyridine in the presence of a base. [8]

Environmental properties

Although pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, introduction of a halogen moiety significantly retards degradation of the pyridine ring. With the exception of 4-chloropyridine, each of the mono- and di-substituted chloropyridines were found to be relatively resistant to microbiological degradation in soil or liquid media. [9] Estimated time for complete degradation was > 30 days. 2-Chloropyridine exhibits extensive volatilization losses from water, less so when present in soil. [10]

Toxicity

The LD50 is 64 mg/kg (dermal, rabbit). [2]

References

  1. ↑ Linnell, Robert (1960). "Notes- Dissociation Constants of 2-Substituted Pyridines". The Journal of Organic Chemistry. 25 (2): 290. doi:10.1021/jo01072a623.
  2. 1 2 3 4 5 Shimizu, Shinkichi; Watanabe, Nanao; Kataoka, Toshiaki; Shoji, Takayuki; Abe, Nobuyuki; Morishita, Sinji; Ichimura, Hisao (2007). "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.
  3. ↑ Narendar, P.; Gangadasu, B.; Ramesh, Ch.; China Raju, B.; Jayathirtha Rao, V. (2004). "Facile and Selective Synthesis of Chloromethylpyridines and Chloropyridines Using Diphosgene/Triphosgene". Synthetic Communications. 34 (6): 1097–1103. doi:10.1081/SCC-120028642. S2CID   95706122.
  4. ↑ Pechmann, H. V.; Baltzer, O. (1891). "Ueber das α-Pyridon (α-Oxypyridin)". Berichte der Deutschen Chemischen Gesellschaft. 24 (2): 3144–3153. doi:10.1002/cber.189102402155.
  5. ↑ Kevin W. C. Poon, Philip A. Albiniak, Gregory B. Dudley (2007). "Protection of Alcohols Using 2-Benzyloxy-1-Methylpyridinium Trifluoromethanesulfonate: Methyl (R)-(-)-3-Benzyloxy-2-Methyl Propanoate". Organic Syntheses. 84: 295. doi:10.15227/orgsyn.084.0295.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ↑ Patrick M. Pollock, Kevin P. Cole (2012). "t-Butyl as a Pyrazole Protecting Group: Preparation and Use of 1-tert-Butyl-3-Methyl-1H-Pyrazole-5-Amine". Organic Syntheses. 89: 537. doi:10.15227/orgsyn.089.0537.
  7. ↑ Cheng, Hefeng; She, Ji. 14. Improved preparation of 2-mercaptopyridine-N-oxide. Zhongguo Yiyao Gongye Zazhi. 1990, 21, (2), pp. 55-56. ISSN   1001-8255
  8. ↑ Botteghi, Carlo; Chelucci, Giorgio; Del Ponte, Gino; Marchetti, Mauro; Paganelli, Stefano (1994). "New Synthetic Route to Pheniramines via Hydroformylation of Functionalyzed Olefins". The Journal of Organic Chemistry. 59 (23): 7125–7127. doi:10.1021/jo00102a044.
  9. ↑ Sims, G. K. and L.E. Sommers. 1986. Biodegradation of pyridine derivatives in soil suspensions. Environmental Toxicology and Chemistry. 5:503-509.
  10. ↑ Sims, G. K. and L.E. Sommers. 1985. Degradation of pyridine derivatives in soil. Journal of Environmental Quality. 14:580-584.
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