Chloroacetone → 8-Bromo-2-methylimidazo[1,2-a]pyridin-7-amine

HRID 1951352Notes

Reaction equation

HRID 1951352 reaction equation
[NH2:1][C:2]1[C:7]([Br:8])=[C:6]([NH2:9])[CH:5]=[CH:4][N:3]=1.Cl[CH2:11][C:12](=O)[CH3:13]>C(O)C>[NH2:9][C:6]1[CH:5]=[CH:4][N:3]2[CH:11]=[C:12]([CH3:13])[N:1]=[C:2]2[C:7]=1[Br:8]

Participants

4

Reactant 2

HCID 6571ChloroacetoneHCID 126562583-Bromopyridine-2,4-diamine

Product 1

HCID 673603208-Bromo-2-methylimidazo[1,2-a]pyridin-7-amineYield 90%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a solution of 2,4-diamino-3-bromopyridine (17) (in Rauckman, B. S, and al. J. Med. Chem. 1980, 23, 384-391) (2.00 g, 10.6 mmol) in ethanol (40 mL) was added chloracetone (3.93 g, 42.5 mmol). The solution was stirred under reflux for 24 h. After cooling to room temperature, the solution was evaporated to dryness. The residue was diluted with water (40 mL) and the resulting solution made basic by the addition of Na2CO3. The solution was extracted with CH2Cl2 and the combinated extracts were dried (Na2SO4), filtered and evaporated under reduced pressure. The crude product was purified by chromatography using CH2Cl2/EtOAc (4/1, v/v) as eluent to afford compound 18 (yield: 90%); mp 158-160° C.; 1H NMR (200 MHz, DMSO-d6) δ 2.19 (s, 3H), 5.78 (brs, 2H), 6.41 (d, 1H, J=7 Hz), 7.36 (s, 1H), 8.07 (d, 1H, J=7 Hz); 13C NMR (100 MHz, DMSO-d6) δ 14.1, 86.2, 104.6, 109.1, 125.5, 140.8, 143.1, 144.0. Anal.

Workup

  1. temperatureunder reflux for 24 h
  2. customthe solution was evaporated to dryness
  3. additionThe residue was diluted with water (40 mL)
  4. additionby the addition of Na2CO3
  5. extractionThe solution was extracted with CH2Cl2
  6. dry with materialthe combinated extracts were dried (Na2SO4)
  7. filtrationfiltered
  8. customevaporated under reduced pressure
  9. customThe crude product was purified by chromatography

Sources & evidence

ORD record
ord-fe39f30b1bbc4490abcc4c8590ec1f96
Source dataset
uspto-grants-2013_03
Patent number
US08404707B2

Reaction notes

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