Hydrogen Bromide → 5,8-Dibromoimidazo[1,2-a]pyrazine

HRID 906206Notes

Reaction equation

HRID 906206 reaction equation
C(O[CH:4](OCC)[CH2:5][Br:6])C.Br.[Br:11][C:12]1[C:13]([NH2:19])=[N:14][C:15](Br)=[CH:16][N:17]=1>CC(O)C>[Br:11][C:12]1[N:17]2[CH:16]=[CH:15][N:14]=[C:4]2[C:5]([Br:6])=[N:19][CH:13]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 510516652-Amino-3,6-dibromopyrazine

Product 1

HCID 534859495,8-Dibromoimidazo[1,2-a]pyrazine

Reagents, catalysts & solvents 1

HCID 3776IsopropanolSolvent

Procedure

Bromoacetaldehyde diethyl acetal (49 mL, 326 mmol) and 48% hydrobromic acid is heated to reflux for 1.5 h, then poured into propan-2-ol (600 mL) and quenched with NaHCO3. After filtering, 3,6-dibromopyrazin-2-yl amine (41.34 g, 163 mmol) is added to the solution and heated at reflux overnight. The reaction is cooled and solvents removed in vacuo, followed by addition of aq. NaHCO3 and extraction with EtOAc. The organic phase is dried over anhydrous MgSO4, filtered, and concentrated in vacuo to afford a brown solid. 1H NMR (250 MHz, CDCl3) δ(ppm) 7.86 (s, 1H), 7.93-7.94 (d, 1H), 7.98-7.99 (d, 1H); m/z (APCI) 278 (M+H)+; m.p 132-135° C.

Workup

  1. temperatureto reflux for 1.5 h
  2. customquenched with NaHCO3
  3. filtrationAfter filtering
  4. temperatureheated
  5. temperatureat reflux overnight
  6. temperatureThe reaction is cooled
  7. customsolvents removed in vacuo
  8. additionfollowed by addition of aq. NaHCO3 and extraction with EtOAc
  9. dry with materialThe organic phase is dried over anhydrous MgSO4
  10. filtrationfiltered
  11. concentrationconcentrated in vacuo
  12. customto afford a brown solid
  13. customm.p 132-135° C.

Sources & evidence

ORD record
ord-ae9923b9f0fd43febe06c545522f763e
Source dataset
uspto-grants-2011_09
Patent number
US08012983B2

Reaction notes

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