Hydrogen Bromide → HCID 178430682, compound

HRID 1809185Notes

Reaction equation

HRID 1809185 reaction equation
[CH2:1](OC(OCC)CBr)[CH3:2].Br.C([O-])(O)=O.[Na+].[NH2:16][C:17]1[C:18]([OH:24])=[N:19][CH:20]=[C:21]([CH3:23])[N:22]=1>CC(O)C.CCOCC>[CH3:23][C:21]1[N:22]2[CH:1]=[CH:2][N:16]=[C:17]2[C:18]([OH:24])=[N:19][CH:20]=1

Participants

7

Reactant 4

HCID 260Hydrogen BromideHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 516892Sodium BicarbonateHCID 178430717HCID 178430717, compound

Product 1

HCID 178430682HCID 178430682, compoundYield 35.4%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 3776IsopropanolSolvent2×

Procedure

Bromoacetaldehyde diethyl acetal (12.2 mL, 81.4 mmol) and a solution of 48% HBr (0.94 mL) are heated at reflux for 1.5 hours, then poured into a suspension of NaHCO3 (1.92 g) in propan-2-ol (31.3 mL). The resulting solid is filtered off and 3-amino-5-methyl-pyrazin-2-ol (3.13 g, 25.0 mmol) is added. The solution is refluxed for 2 hours then left to stand overnight and the solid formed washed with IPA and ether. The solid is added to a solution of DCM (60 mL) and NaHCO3 sat. (30 mL), the two layers are separated and the aqueous phase is extracted with DCM. The combined organic layers are dried with MgSO4 anh., filtered and evaporated to give a brown solid product. The aqueous phase is again extracted with a CHCl3/IPA 9/1, dried with MgSO4 anh., filtered and concentrated to give a brown solid product. The IPA and Ether used previously for washing the solid are combined, evaporated and submitted to the same process described previously to give a brown solid quite impurified from the DCM extraction and a brown solid with the CHCl3/IPA of similar purity to the one obtained beforehand. The products resulting from the first DCM extraction and the two CHCl3/IPA extraction are combined and washed with cold MeOH to give 5-Methyl-imidazo[1,2-a]pyrazin-8-ol as a pale yellow solid (1.32 g) that is submitted into the next step without further purification.

Workup

  1. temperatureat reflux for 1.5 hours
  2. filtrationThe resulting solid is filtered off
  3. temperatureThe solution is refluxed for 2 hours
  4. waitthen left
  5. customthe solid formed
  6. washwashed with IPA and ether
  7. additionThe solid is added to a solution of DCM (60 mL) and NaHCO3 sat. (30 mL)
  8. customthe two layers are separated
  9. extractionthe aqueous phase is extracted with DCM
  10. dry with materialThe combined organic layers are dried with MgSO4 anh.
  11. filtrationfiltered
  12. customevaporated
  13. customto give a brown solid product
  14. extractionThe aqueous phase is again extracted with a CHCl3/IPA 9/1
  15. dry with materialdried with MgSO4 anh.
  16. filtrationfiltered
  17. concentrationconcentrated
  18. customto give a brown solid product
  19. washfor washing the solid
  20. customevaporated
  21. customto give a brown solid
  22. extractionquite impurified from the DCM extraction
  23. customThe products resulting from the first DCM extraction
  24. extractionthe two CHCl3/IPA extraction
  25. washwashed with cold MeOH

Sources & evidence

ORD record
ord-893bc66c582a44f5a09fd64b24c57154
Source dataset
uspto-grants-2013_01
Patent number
US08362018B2

Reaction notes

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