Phosphorus sulfide (P2S5) → 5-Pyrazin-2-yldithiole-3-thione

HRID 1439248Notes

Reaction equation

HRID 1439248 reaction equation
C[S:2][C:3]([S:13]C)=[CH:4][C:5]([C:7]1[CH:12]=[N:11][CH:10]=[CH:9][N:8]=1)=O.P12(SP3(SP(SP(S3)(S1)=S)(=S)S2)=S)=[S:16]>C1(C)C(C)=CC=CC=1.ClCCCl.C(=S)=S>[N:8]1[CH:9]=[CH:10][N:11]=[CH:12][C:7]=1[C:5]1[S:16][S:2][C:3](=[S:13])[CH:4]=1

Participants

6

Reactant 2

HCID 14817Phosphorus sulfide (P2S5)HCID 213988833,3-Bis(methylsulfanyl)-1-(pyrazin-2-yl)prop-2-en-1-one

Product 1

HCID 1823325-Pyrazin-2-yldithiole-3-thioneYield 17%

Reagents, catalysts & solvents 3

HCID 111,2-DichloroethaneSolventHCID 6348Carbon DisulfideSolventHCID 7237O-XyleneSolvent

Conditions

Temperature
20 °C

Procedure

3,3-bis-Methylthio-1-(pyrazin-2-yl)-prop-2-en-1-one (2.26 g.) is added in the course of about one minute to a boiling suspension of phosphorus pentasulphide (7.1 g.) in anhydrous xylene (140 cc.). Heating under reflux is continued for one hour after the end of the addition, and the reaction mixture is then cooled to a temperature of about 20° C. An insoluble product is filtered off and washed with 1,2-dichloroethane (200 cc.). The filtrate is concentrated to dryness under reduced pressure and the residue obtained is taken up in 1,2-dichloroethane (100 cc.). An insoluble product is filtered off and washed with 1,2-dichloroethane (4 × 50 cc.). The filtrate is extracted successively with a 10% aqueous sodium carbonate solution (100 cc.) and with water (2 × 100 cc.) and is then dried over magnesium sulphate. After filtration of the dried solution, and concentration to dryness under reduced pressure (30 mm Hg), the residue obtained is suspended in carbon disulphide (50 cc.). The insoluble product is filtered off and taken up in boiling 1,2 -dichloroethane (25 cc.). The boiling suspension is filtered and then cooled. A product precipitates and is filtered off and then washed with 1,2-dichloroethane (2 × 2 cc.). After drying, 5-(pyrazin-2-yl)-1,2-dithiole-3-thione (0.36 g.) melting at 196° C. is obtained.

Workup

  1. temperatureHeating
  2. temperatureunder reflux
  3. additionafter the end of the addition
  4. filtrationAn insoluble product is filtered off
  5. washwashed with 1,2-dichloroethane (200 cc.)
  6. concentrationThe filtrate is concentrated to dryness under reduced pressure
  7. customthe residue obtained
  8. filtrationAn insoluble product is filtered off
  9. washwashed with 1,2-dichloroethane (4 × 50 cc.)
  10. extractionThe filtrate is extracted successively with a 10% aqueous sodium carbonate solution (100 cc.) and with water (2 × 100 cc.)
  11. dry with materialis then dried over magnesium sulphate
  12. filtrationAfter filtration of the dried solution, and concentration to dryness under reduced pressure (30 mm Hg)
  13. customthe residue obtained
  14. filtrationThe insoluble product is filtered off
  15. filtrationThe boiling suspension is filtered
  16. temperaturecooled
  17. customA product precipitates
  18. filtrationis filtered off
  19. washwashed with 1,2-dichloroethane (2 × 2 cc.)
  20. customAfter drying

Sources & evidence

ORD record
ord-e79bda0edb2b496fa8da9794101d50b7
Source dataset
uspto-grants-1977_11
Patent number
US04058611

Reaction notes

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