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

HRID 2183865Notes

Reaction equation

HRID 2183865 reaction equation
[NH2:1][C:2]1[N:7]=[CH:6][CH:5]=[CH:4][N:3]=1.[CH2:8](OC(OCC)CBr)[CH3:9].Br>C(O)C>[N:1]1[CH:8]=[CH:9][N:3]2[CH:4]=[CH:5][CH:6]=[N:7][C:2]=12

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 79782-AminopyrimidineHCID 74852Ethane, 2-bromo-1,1-diethoxy-

Product 1

HCID 577018Imidazo(1,2-a)pyrimidineYield 82%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A solution of 2-aminopyrimidine (0.5 g, 5.26 mmol), bromoacetaldehyde diethyl acetal (2.07 g, 10.5 mmol) and 48% aqueous hydrobromic acid (0.5 ml) in ethanol (5 ml) was heated at reflux for 18 h. The reaction was cooled and pre-adsorbed directly onto silica gel. Purification by flash chromatography eluting with dichloromethane (containing 1% conc. ammonia) on a gradient of methanol (1-3%) gave a solid which was triturated with 5% diethyl ether in isohexane to afford imidazo[1,2-α]pyrimidine (0.51 g, 82%) as a tan solid: δH (400 MHz, CDCl3) 6.92 (1H, dd, J 7 and 4), 7.59 (1H, d, J 1), 7.84 (1H, d, J 1), 8.49 (1H, dd, J 7 and 2), 8.58 (1H, dd, J 7 and 2).

Workup

  1. temperatureat reflux for 18 h
  2. temperatureThe reaction was cooled and pre-adsorbed directly onto silica gel
  3. customPurification by flash chromatography
  4. washeluting with dichloromethane (containing 1% conc. ammonia) on a gradient of methanol (1-3%)
  5. customgave a solid which
  6. customwas triturated with 5% diethyl ether in isohexane

Sources & evidence

ORD record
ord-01194f21a40a4246b8fad97ae3ec779a
Source dataset
uspto-grants-2005_05
Patent number
US06900215B2

Reaction notes

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