Phosphorus oxychloride → 2-Chloro-5-(trifluoromethyl)pyrazine

HRID 734337Notes

Reaction equation

HRID 734337 reaction equation
N[C:2]1[CH:7]=[N:6][C:5]([C:8]([F:11])([F:10])[F:9])=[CH:4][N:3]=1.FC(F)(F)C1N=CC(=O)NC=1.C([O-])(O)=O.[Na+].O=P(Cl)(Cl)[Cl:30]>OS(O)(=O)=O>[Cl:30][C:2]1[CH:7]=[N:6][C:5]([C:8]([F:11])([F:10])[F:9])=[CH:4][N:3]=1

Participants

6

Reactant 4

HCID 24813Phosphorus oxychlorideHCID 516892Sodium BicarbonateHCID 133411155-(Trifluoromethyl)pyrazin-2-amineHCID 199158085-(Trifluoromethyl)pyrazin-2-ol2×

Product 1

HCID 189876452-Chloro-5-(trifluoromethyl)pyrazine

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidCatalyst

Procedure

2-Amino-5-trifluoromethylpyrazine (Miesel, U.S. Pat. No. 4,293,552) was converted into 5-trifluoromethylpyrazin-2-one (Fitzjohn, EP 408196). 5-Trifluoromethylpyrazin-2-one (0.5 g) was heated at reflux in POCl3 (3 ml) containing 1 drop of conc. H2SO4 for 3 h. The cooled mixture was poured onto ice and brought to pH 5 by addition of solid NaHCO3 and extracted (3×) with diethyl ether. The ethereal extracts were washed with water and brine, dried (Na2SO4) and evaporated to give the title compound (D31) as a light yellow oil (0.2 g) which was sufficiently pure for use without further purification. 1H NMR δ [CDCl3]: 8.72 (1H, s), 8.76 (1H, s).

Workup

  1. additionThe cooled mixture was poured onto ice
  2. extractionextracted (3×) with diethyl ether
  3. washThe ethereal extracts were washed with water and brine
  4. dry with materialdried (Na2SO4)
  5. customevaporated

Sources & evidence

ORD record
ord-5d6aaf11f8614af08afc87ada03a9c71
Source dataset
uspto-grants-2009_09
Patent number
US07592347B2

Reaction notes

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