Potassium tert-butoxide → 2-bromo-5H-pyrrolo[2,3-b]pyrazine

HRID 716028Notes

Reaction equation

HRID 716028 reaction equation
CC(C)([O-])C.[K+].[Br:7][C:8]1[N:9]=[C:10]([C:15]#[C:16][Si](C)(C)C)[C:11]([NH2:14])=[N:12][CH:13]=1>C1COCC1.C(OCC)(=O)C>[Br:7][C:8]1[N:9]=[C:10]2[CH:15]=[CH:16][NH:14][C:11]2=[N:12][CH:13]=1

Participants

5

Reactant 2

HCID 23665647Potassium tert-butoxideHCID 533931895-Bromo-3-((trimethylsilyl)ethynyl)pyrazin-2-amine

Product 1

HCID 250673082-bromo-5H-pyrrolo[2,3-b]pyrazineYield 58.7%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
65 °C

Procedure

To a 250 ml three necked round bottom flask, potassium tert-butoxide (4.2 g, 0.037 mole) was taken in THF (50 ml). To this, 5-bromo-3-((trimethylsilyl)ethynyl)pyrazine-2-amine (10.0 g, 0.037 mole) in THF (50 ml) was added dropwise at RT over 20 min under nitrogen atmosphere and the reaction mixture was stirred for 30 min at same temperature and 60 min at 65° C. The completion of the reaction was monitored by TLC using hexanes:ethyl acetate (8:2) as a mobile phase. After completion of the reaction, the reaction mixture was cooled to RT and diluted with ethyl acetate, filtered through high flow. Filtrate was collected and washed with water. The layers were separated and the aq. layer was re-extracted with ethyl acetate. The combined organic layer was dried over Na2SO4, filtered, and concentrated to afford crude product which was subjected for the column purification. The crude compound was purified using column purification by eluting the compound with 15-20% ethyl acetate in hexanes to yield 4.3 g of 2-bromo-5H-pyrrolo[2,3-b]pyrazine.

Workup

  1. customAfter completion of the reaction
  2. temperaturethe reaction mixture was cooled to RT
  3. filtrationfiltered through high flow
  4. customFiltrate was collected
  5. washwashed with water
  6. customThe layers were separated
  7. extractionthe aq. layer was re-extracted with ethyl acetate
  8. dry with materialThe combined organic layer was dried over Na2SO4
  9. filtrationfiltered
  10. concentrationconcentrated
  11. customto afford crude product which
  12. customwas subjected for the column purification
  13. customThe crude compound was purified
  14. customcolumn purification
  15. washby eluting the compound with 15-20% ethyl acetate in hexanes

Sources & evidence

ORD record
ord-92f18407f9b0447d87f810266408126b
Source dataset
uspto-grants-2015_11
Patent number
US09187487B2

Reaction notes

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