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

HRID 1439251Notes

Reaction equation

HRID 1439251 reaction equation
[N:1]1[CH:6]=[CH:5][N:4]=[CH:3][C:2]=1[C:7]1[S:11][S:10][C:9](=O)[CH:8]=1.P12(SP3(SP(SP(S3)(S1)=S)(=S)S2)=S)=[S:14]>O1CCOCC1.C(#N)C>[N:1]1[CH:6]=[CH:5][N:4]=[CH:3][C:2]=1[C:7]1[S:11][S:10][C:9](=[S:14])[CH:8]=1

Participants

5

Reactant 2

HCID 14817Phosphorus sulfide (P2S5)HCID 21329209HCID 21329209, compound

Product 1

HCID 1823325-Pyrazin-2-yldithiole-3-thioneYield 170.2%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolvent2×HCID 312751,4-DioxaneSolvent2×

Conditions

Temperature
100 °C

Procedure

A mixture of 5-(pyrazin-2-yl)-1,2-dithiole-3-one (2 g.) and phosphorus pentasulphide (2.3 g.) in dioxan (35 cc.) is heated for 15 minutes at 100° C., whilst stirring. The red suspension obtained is diluted whilst hot with acetonitrile (35 cc.). The solution is decanted and the precipitate obtained is taken up with a hot mixture (2 × 50 cc.) of dioxan and acetonitrile (50:50 by volume). The combined organic phases are filtered hot, diluted with distilled water (250 cc.), and the requisite amount of a 4N aqueous ammonia solution to adjust the pH to 7. The brown precipitate formed is filtered off, washed with distilled water (2 × 25 cc.) and then with diethyl ether (2 × 10 cc.) and dried. 5-(Pyrazin-2-yl)-1,2-dithiole-3-thione (1.87 g.) melting at 200°-201° C. is thus obtained.

Workup

  1. customThe red suspension obtained
  2. customThe solution is decanted
  3. customthe precipitate obtained
  4. filtrationThe combined organic phases are filtered hot
  5. additiondiluted with distilled water (250 cc.)
  6. customThe brown precipitate formed
  7. filtrationis filtered off
  8. washwashed with distilled water (2 × 25 cc.)
  9. dry with materialwith diethyl ether (2 × 10 cc.) and dried

Sources & evidence

ORD record
ord-2142235b40774844b130faded1e5f396
Source dataset
uspto-grants-1977_11
Patent number
US04058611

Reaction notes

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