Pyrithione

Pyrithione

Interconversion of pyrithione tautomers
thione form on the left, thiol form on the right
Names
Preferred IUPAC name
1-Hydroxy-2(1H)-pyridinethione (thione)
2-Pyridinethiol 1-oxide (thiol)
Other names
Omadine
thione: 1-Hydroxypyridine-2-thione
      N-Hydroxypyridine-2-thione
thiol: 2-Mercaptopyridine monoxide
        2-Mercaptopyridine N-oxide
        2-Mercaptopyridine 1-oxide
Identifiers
3D model (JSmol)
109936
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.013.027 Edit this at Wikidata
EC Number
  • 214-328-9
  • thione: 214-329-4
913415
UNII
  • thione: InChI=1S/C5H5NOS/c7-6-4-2-1-3-5(6)8/h1-4,7H
    Key: YBBJKCMMCRQZMA-UHFFFAOYSA-N
  • thiol: InChI=1S/C5H5NOS/c7-6-4-2-1-3-5(6)8/h1-4,8H
    Key: FGVVTMRZYROCTH-UHFFFAOYSA-N
  • thiolate salt: InChI=1S/C5H5NOS.Na/c7-6-4-2-1-3-5(6)8;/h1-4,8H;/q;+1/p-1
    Key: WNGMMIYXPIAYOB-UHFFFAOYSA-M
  • thione salt: InChI=1S/C5H4NOS.Na/c7-6-4-2-1-3-5(6)8;/h1-4H;/q-1;+1
    Key: XNRNJIIJLOFJEK-UHFFFAOYSA-N
  • thione: c1ccn(c(=S)c1)O
  • thiol: C1=CC=[N+](C(=C1)S)[O-]
  • thiolate salt: c1cc[n+](c(c1)[S-])[O-].[Na+]
  • thione salt: c1ccn(c(=S)c1)[O-].[Na+]
Properties
C5H5NOS
Molar mass 127.16 g·mol−1
Appearance Beige crystalline powder
Melting point 70 to 73 °C (158 to 163 °F; 343 to 346 K)
2.5 g L−1 at 20 °C
Solubility Soluble: benzene, chloroform, dichloromethane, dimethylformamide, dimethylsulfoxide, ethyl acetate[1]
Slightly soluble: diethyl ether, ethanol, methyl tert-butyl ether, tetrahydrofuran[1]
Acidity (pKa) −1.95 (proton addition), 4.6[2][3]
Hazards
GHS labelling:
GHS06: Toxic
Danger
H301, H315, H319, H335
P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Pyrithione is the common name of an organosulfur compound with molecular formula C
5H
5NOS, chosen as an abbreviation of pyridinethione, and found in the Persian shallot.[4] It exists as a pair of tautomers, the major form being the thione 1-hydroxy-2(1H)-pyridinethione and the minor form being the thiol 2-mercaptopyridine N-oxide; it crystallises in the thione form.[5] It is usually prepared from either 2-bromopyridine,[1] 2-chloropyridine,[6][7] or 2-chloropyridine N-oxide,[8] and is commercially available as both the neutral compound and its sodium salt.[1] It is used to prepare zinc pyrithione,[9][10] which is used primarily to treat dandruff and seborrhoeic dermatitis in medicated shampoos,[11][12] though is also an anti-fouling agent in paints.[13]

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  2. ^ Cite error: The named reference pKa was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference pKa2 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference PersianShallot was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference SolidThione was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference 2-mercaptopyridine was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference UroniumChloropyridine was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Rompp was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference ZnP2patent1 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference ZnP2patent2 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference ZnDermatology was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SebDerm was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference ACS was invoked but never defined (see the help page).