2-Aminopyridine → 1-{2-Methylimidazo[1,2-a]pyridin-3-yl}ethan-1-one

HRID 416278Notes

Reaction equation

HRID 416278 reaction equation
N(C1(C#N)CCCCC1)=NC1(C#N)CCCCC1.[CH3:19][C:20](=[O:25])[CH2:21][C:22](=O)[CH3:23].BrN1C(=O)CCC1=O.[N:34]1[CH:39]=[CH:38][CH:37]=[CH:36][C:35]=1[NH2:40]>C(Cl)(Cl)Cl.CCOC(C)=O.CO>[CH3:23][C:22]1[N:40]=[C:35]2[CH:36]=[CH:37][CH:38]=[CH:39][N:34]2[C:21]=1[C:20](=[O:25])[CH3:19]

Participants

7

Reactant 4

HCID 104392-AminopyridineHCID 31261AcetylacetoneHCID 67184N-bromobutanimideHCID 749781,1'-Azobis(cyclohexanecarbonitrile)

Product 1

HCID 27352551-{2-Methylimidazo[1,2-a]pyridin-3-yl}ethan-1-oneYield 35.5%

Reagents, catalysts & solvents 2

HCID 6212ChloroformSolventHCID 21584119Ethylacetate methanolSolvent

Procedure

1,1′-Azobis(cyclohexanecarbonitrile) (catalytic amount) was added to a solution of pentane-2,4-dione (1.00 g, 9.99 mmol) and N-bromosuccinimide (1.96 g, 10.99 mmol) in CHCl3 (20 mL). The reaction mixture was stirred for 1 hour, filtered and the filtrate was concentrated under reduced pressure. The residue was re-dissolved in a 1:1 mixture of THF/Et2O (20 mL), then pyridin-2-amine (723 mg, 7.68 mmol) was added and the reaction mixture was refluxed overnight. After cooling the solvent was removed under reduced pressure and the residue was purified by column chromatography, eluents EtOAc, then EtOAc-MeOH (96:4), to afford the title compound (475 mg 35% yield). 1H NMR (DMSO-d6) δ (ppm): 9.59 (dt, J=6.8, 1.4 Hz, 1H), 7.68 (dt, J=8.8, 1.2 Hz, 1H), 7.56 (ddd, J=8.8, 6.8, 1.4 Hz, 1H), 7.17 (td, J=6.8, 1.4 Hz, 1H), 2.72 (s, 3H), 2.58 (s, 3H). MS (m/z): 174.20 (calc) 175.1 (MH+) (found).

Workup

  1. filtrationfiltered
  2. concentrationthe filtrate was concentrated under reduced pressure
  3. dissolutionThe residue was re-dissolved in a 1:1 mixture of THF/Et2O (20 mL)
  4. temperaturethe reaction mixture was refluxed overnight
  5. temperatureAfter cooling the solvent
  6. customwas removed under reduced pressure
  7. customthe residue was purified by column chromatography, eluents EtOAc

Sources & evidence

ORD record
ord-abcb5d11aedb4ab692fcdbf86af4f307
Source dataset
uspto-grants-2012_01
Patent number
US08088805B2

Reaction notes

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