Hydrogen Bromide → Imidazo(1,2-a)pyrazine

HRID 1371359Notes

Reaction equation

HRID 1371359 reaction equation
[NH2:1][C:2]1[CH:7]=[N:6][CH:5]=[CH:4][N:3]=1.[CH2:8](OC(OCC)CBr)[CH3:9].Br.[OH-].[Na+]>C(O)C.CC(O)C.C(Cl)Cl>[N:1]1[CH:8]=[CH:9][N:3]2[CH:4]=[CH:5][N:6]=[CH:7][C:2]=12

Participants

7

Reactant 4

HCID 260Hydrogen BromideHCID 14798Sodium HydroxideHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 78747Aminopyrazine

Product 1

HCID 2771670Imidazo(1,2-a)pyrazineYield 94%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 21966342Isopropanol methylene chlorideSolvent

Procedure

To a solution of aminopyrazine (5 g, 53 mol, 1 eq.) in ethanol (212 ml) was added bromoacetaldehyde diethylacetal (12 ml, 80 mol, 1.5 eq.) and HBr (48%, 26.5 ml). The mixture was heated at 70–80° C. for 17 hours. The mixture was then cooled to rt (room temperature), then a mixture of 1N NaOH (200 ml) and 20% IPA/DCM (isopropyl alcohol/Dichloromethane) was added to the reaction mixture. The combined organic layer was dried over sodium sulfate and concentrated to afford 5.9 g of brown solid of imidazo[1,2-a]pyrazine (yield 94%).

Workup

  1. temperatureThe mixture was heated at 70–80° C. for 17 hours
  2. additionwas added to the reaction mixture
  3. dry with materialThe combined organic layer was dried over sodium sulfate
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-87d68747182b49e1a0903588c9bee4fb
Source dataset
uspto-grants-2007_01
Patent number
US07157460B2

Reaction notes

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