Tetrahydrofuran → 6,8-Dibromoimidazo[1,2-a]pyrazine

HRID 925584Notes

Reaction equation

HRID 925584 reaction equation
[NH2:1][C:2]1[C:7]([Br:8])=[N:6][C:5]([Br:9])=[CH:4][N:3]=1.[CH2:10]1COC[CH2:11]1.C(OC(OCC)CBr)C>O>[Br:9][C:5]1[N:6]=[C:7]([Br:8])[C:2]2[N:3]([CH:10]=[CH:11][N:1]=2)[CH:4]=1

Participants

5

Reactant 3

HCID 8028TetrahydrofuranHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 6200042-Amino-3,5-dibromopyrazine

Product 1

HCID 150258436,8-Dibromoimidazo[1,2-a]pyrazine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a stirred suspension of 2-amino-3,5-dibrompyrazine (427 g, 1688 mmol) in water (6.4 L)/THF (482 mL), at rt was added bromacetaldehyde-diethylacetal (998 g, 5065 mmol) in one portion. After stirring under reflux for 4 h, the clear orange solution was stirred for an additional 15 h at rt. The suspension was filtered, and the remaining solid was washed with MeOH (2 L) and dried in vaccuo at 60° C. to yield 6,8-dibromo-imidazo[1,2-a]pyrazine as an off-white solid (500 g, 107% with residual MeOH): 1H-NMR (300 MHz, d6-DMSO): δ=9.02 (s, 1H), 8.23 (d, 1H), 7.89 (d, 1H) ppm. UPLC-MS: RT=0.80 min; m/z 277.9 [MH+]; required MW=276.9.

Workup

  1. temperatureunder reflux for 4 h
  2. stirringthe clear orange solution was stirred for an additional 15 h at rt
  3. filtrationThe suspension was filtered
  4. washthe remaining solid was washed with MeOH (2 L)
  5. customdried in vaccuo at 60° C.

Sources & evidence

ORD record
ord-a8547d7fb4b44d1dbf35917924521636
Source dataset
uspto-grants-2016_03
Patent number
US09284317B2

Reaction notes

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