4-Ethoxycarbonyl-5-(pyrazin-2-yl)-1,2-dithiole-3-thione → 4-Carboxy-5-(pyrazin-2-yl)-1,2-dithiole-3-thione

HRID 614381Notes

Reaction equation

HRID 614381 reaction equation
C([O:3][C:4]([C:6]1[C:7](=[S:17])[S:8][S:9][C:10]=1[C:11]1[CH:16]=[N:15][CH:14]=[CH:13][N:12]=1)=[O:5])C>C(O)(=O)C.S(=O)(=O)(O)O.O>[C:4]([C:6]1[C:7](=[S:17])[S:8][S:9][C:10]=1[C:11]1[CH:16]=[N:15][CH:14]=[CH:13][N:12]=1)([OH:5])=[O:3]

Participants

5

Reactant 1

HCID 213292104-Ethoxycarbonyl-5-(pyrazin-2-yl)-1,2-dithiole-3-thione

Product 1

HCID 213291664-Carboxy-5-(pyrazin-2-yl)-1,2-dithiole-3-thioneYield 72.1%

Reagents, catalysts & solvents 3

HCID 176Acetic AcidSolventHCID 962WaterSolventHCID 1118Sulfuric AcidSolvent

Conditions

Temperature
20 °C

Procedure

A solution of 4-ethoxycarbonyl-5-(pyrazin-2-yl)-1,2-dithiole-3-thione (150 g) [prepared as described in Example 31] in acetic acid (6750 cc), concentrated sulphuric acid (515 cc) and water (515 cc) is heated for 2 hours under reflux. After cooling, the product which crystallises is filtered off and washed successively with acetic acid (100 cc) and carbon disulphide (2 × 100 cc). This product is then suspended in water (1350 cc) and stirred for 48 hours at a temperature of about 20° C. The insoluble product is then filtered off and washed with water (2 × 250 cc). After drying, 4-carboxy-5-(pyrazin-2-yl)-1,2-dithiole-3-thione (97.5 g), melting at 225° C., is obtained.

Workup

  1. temperatureunder reflux
  2. temperatureAfter cooling
  3. customthe product which crystallises
  4. filtrationis filtered off
  5. washwashed successively with acetic acid (100 cc) and carbon disulphide (2 × 100 cc)
  6. filtrationThe insoluble product is then filtered off
  7. washwashed with water (2 × 250 cc)
  8. customAfter drying

Sources & evidence

ORD record
ord-84604ae6432f406a823f230a31f77332
Source dataset
uspto-grants-1979_03
Patent number
US04144339

Reaction notes

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