Potassium Hydroxide → 5-Chloro-2,3-dimethylpyrazine

HRID 383862Notes

Reaction equation

HRID 383862 reaction equation
[CH3:1][C:2]1[C:7]([CH3:8])=[N:6][CH:5]=[CH:4][N+:3]=1[O-].[OH-].[K+].O=P(Cl)(Cl)[Cl:14]>>[Cl:14][C:5]1[N:6]=[C:7]([CH3:8])[C:2]([CH3:1])=[N:3][CH:4]=1

Participants

4

Reactant 3

HCID 14797Potassium HydroxideHCID 24813Phosphorus oxychlorideHCID 124071632,3-Dimethyl-1-oxo-1lambda~5~-pyrazine

Product 1

HCID 126003905-Chloro-2,3-dimethylpyrazine

Procedure

2,3-Dimethyl-pyrazine 1-oxide (25 g, 0.2 mol) was dissolved in POCl3 (200 mL) under cooling. The mixture was gradually heated to reflux and stirred for 2 hours. After cooling, the reaction mixture was poured onto ice, basified to pH 8 with a saturated KOH solution under cooling and extracted with EtOAc. The combined organics were dried over Na2SO4 and concentrated. The residue was purified by column (P.E./EtOAc 100:1-60:1) to obtain 5-chloro-2,3-dimethylpyrazine. 1HNMR (CDCI3, 300 MHz) δ 8.31 (s, 1H), 2.53 (s, 6H). MS (ESI) m/e (M+H+) 143.2.

Workup

  1. temperatureunder cooling
  2. temperatureThe mixture was gradually heated
  3. temperatureto reflux
  4. temperatureAfter cooling
  5. additionthe reaction mixture was poured onto ice
  6. temperatureunder cooling
  7. extractionextracted with EtOAc
  8. dry with materialThe combined organics were dried over Na2SO4
  9. concentrationconcentrated
  10. customThe residue was purified by column (P.E./EtOAc 100:1-60:1)

Sources & evidence

ORD record
ord-635e52b182544f698bd398bf591bfeba
Source dataset
uspto-grants-2013_02
Patent number
US08367691B2

Reaction notes

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