5-(Trifluoromethyl)pyrazin-2-amine → 5-(Trifluoromethyl)pyrazin-2-ol

HRID 1089682Notes

Reaction equation

HRID 1089682 reaction equation
N([O-])=[O:2].[Na+].N[C:6]1[CH:11]=[N:10][C:9]([C:12]([F:15])([F:14])[F:13])=[CH:8][N:7]=1>S(=O)(=O)(O)O>[F:13][C:12]([F:15])([F:14])[C:9]1[N:10]=[CH:11][C:6](=[O:2])[NH:7][CH:8]=1

Participants

4

Reactant 2

HCID 133411155-(Trifluoromethyl)pyrazin-2-amineHCID 23668193Sodium Nitrite

Product 1

HCID 199158085-(Trifluoromethyl)pyrazin-2-ol

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent2×

Procedure

Sodium nitrite (0.21 g) was added in one batch to concentrated sulphuric acid (2.5 ml) at 2° C. The reaction mixture was then stirred, allowed to warm to room temperature and then heated to 40° C. for 10 minutes. The resulting solution was then cooled to 3° C. and a solution of 2-amino-5-trifluoromethylpyrazine (prepared by the method of Miesel, U.S. Pat. No. 4,293,552, 0.5 g) in concentrated sulphuric acid (3.5 ml) added dropwise. The reaction temperature was not allowed to rise above 5° C. during the addition. After stirring at 5° C. for 10 minutes, the reaction mixture was allowed to warm to room temperature and after 10 minutes heated to 40° C. for 10 minutes. The reaction mixture was then added to ice. Vigorous gas evolution was noted. The mixture was then extracted with ethyl acetate, the organic phase washed with brine, dried with sodium sulphate and evaporated under reduced pressure to give 5-trifluoromethylpyrazine-2-one as a yellow solid.

Workup

  1. temperatureheated to 40° C. for 10 minutes
  2. temperatureThe resulting solution was then cooled to 3° C.
  3. additionto rise above 5° C. during the addition
  4. stirringAfter stirring at 5° C. for 10 minutes
  5. temperatureto warm to room temperature and after 10 minutes
  6. temperatureheated to 40° C. for 10 minutes
  7. additionThe reaction mixture was then added to ice
  8. extractionThe mixture was then extracted with ethyl acetate
  9. washthe organic phase washed with brine
  10. dry with materialdried with sodium sulphate
  11. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-4c7128b5a9924892a72ead4d4b16c8f7
Source dataset
uspto-grants-1992_01
Patent number
US05079251

Reaction notes

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