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

HRID 507277Notes

Reaction equation

HRID 507277 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 (CDCl3, 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-33483f4992e64b1487d6f3b18f40440d
Source dataset
uspto-grants-2010_08
Patent number
US07786141B2

Reaction notes

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