Pyrithione

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Structural formula
Structure of pyrithione
General
Surname Pyrithione
other names
  • Pyridine-2-thiol-1-oxide
  • Omadin
  • PTO
Molecular formula C 5 H 5 NOS
Brief description

beige-colored to gray-black solid with a foul odor

External identifiers / databases
CAS number
  • 1121-30-8 (Enthiol form)
  • 1121-31-9 (thione form)
PubChem 1570
Wikidata Q2119951
properties
Molar mass 127.18 g mol −1
Physical state

firmly

boiling point

69-72 ° C

solubility

sparingly soluble in water (2.5 g l −1 at 20 ° C)

safety instructions
GHS labeling of hazardous substances
06 - Toxic or very toxic

danger

H and P phrases H: 301-315-319-335
P: 261-301 + 310-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pyrithione is an organic compound . It consists of a pyridine ring , which is oxidized on the nitrogen atom ( pyridine- N -oxide ) and has a thiocarbonyl function in the 2-position . It is a fungicide and a bactericide .

presentation

For the preparation of the compound is first 2-chloropyridine N -oxide with sodium hydrogen sulfide to the reaction brought, from which the sodium salt of pyrithione is formed. Pyrithione can be released from this by neutralization with acids .

Synthesis of pyrithione

properties

Pyrithione is a foul-smelling solid that melts at 69–72 ° C. It has only a low solubility in water of 2.5 g · l −1 at 20 ° C.

There is an equilibrium between the tautomeric enthiol and thione forms ( thiolactam-thiolactim tautomerism ).

Tautomeric equilibrium of pyrithione

use

Structure of zinc pyrithione

Pyrithione can be used to make zinc pyrithione , which is used against dander and in anti-fungal paints. Sodium pyrithione , used as an antifungal agent , can be made by reacting with sodium salts . The bactericide and fungicide dipyrithione is produced by oxidative dimerization .

Pyrithione can also be used to produce copolymers of cellulose . This polymerization takes place radically .

In chemistry, pyrithione is used to produce Barton esters , which are required for Barton-McCombie decarboxylation . Derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NDB-Cl) serves pyrithione in chemical analysis to UV - fluorescence -type detection in HPLC measurements.

Derivatization of pyrithione with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole

Individual evidence

  1. ↑ a b c data sheet Pyrithione at AlfaAesar, accessed on June 6, 2010 ( PDF )(JavaScript required) .
  2. ↑ a b sheet pyrithione from Acros, accessed on 6 June of 2010.
  3. ↑ a b c d e f g h Entry on pyrithione. In: Römpp Online . Georg Thieme Verlag, accessed on June 10, 2014.
  4. ↑ a b Data sheet 2-Mercaptopyridine N-oxide from Sigma-Aldrich , accessed on April 22, 2011 ( PDF ).
  5. ^ CJ Chandler, IH Segel: "Mechanism of the antimicrobial action of pyrithione: effects on membrane transport, ATP levels, and protein synthesis", in: Antimicrob. Agents Chemother. , 1978 , 14 , pp. 60-68; PMC 352405 (free full text, PDF).