Potassium Carbonate → 8-Chloro-2-(3-methoxyphenyl)imidazo[1,2-a]pyridine

HRID 1295874Notes

Reaction equation

HRID 1295874 reaction equation
[Cl:1][C:2]1[C:3]([NH2:8])=[N:4][CH:5]=[CH:6][CH:7]=1.Br[CH2:10][C:11]([C:13]1[CH:18]=[CH:17][CH:16]=[C:15]([O:19][CH3:20])[CH:14]=1)=O.C(=O)([O-])[O-].[K+].[K+]>C(O)C>[Cl:1][C:2]1[C:3]2[N:4]([CH:10]=[C:11]([C:13]3[CH:18]=[CH:17][CH:16]=[C:15]([O:19][CH3:20])[CH:14]=3)[N:8]=2)[CH:5]=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 101294Bromomethyl 3-methoxyphenyl ketoneHCID 6932672-Amino-3-chloropyridine

Product 1

HCID 113689278-Chloro-2-(3-methoxyphenyl)imidazo[1,2-a]pyridine

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a solution of 3-chloro-2-pyridinamine (4.8 g, 37.4 mmol) and 2-bromo-1-(3-methoxyphenyl)ethanone (8.56 g, 37.4 mmol) in ethanol (30 mL) was added potassium carbonate (5.15 g, 37.4 mmol) and the resultant solution was heated at reflux for 17 hours. The reaction mixture was cooled to room temperature and concentrated in vacuo. The resultant residue was taken up in dichloromethane, washed with water and then brine. The aqueous layer was extracted with dichloromethane and the combined organics dried over magnesium sulfate. Filtration and concentration followed by recrystallization of the residue from ethyl acetate-hexanes reulted in 8-chloro-2-(3-methoxyphenyl)imidazo[1,2-α]pyridine (6.7 g, 70%) as a tan powder. 1H NMR (CDCl3): δ 8.03 (d, 1 H), 7.89 (s, 1 H), 7.57–7.52 (m, 2 H), 7.33 (t, 1 H), 7.23 (d, 1 H), 6.89 (dd, 1 H), 6.71 (t, 1 H), 3.89 (s, 3 H); 13C NMR (CDCl3): δ 159.94, 146.31, 142.96, 134.61, 129.65, 124.30, 123.58, 123.26, 118.81, 114.33, 112.02, 111.44, 109.91, 55.39; MS m/z 259 (M+1); Anal. Calcd for C14H11ClN2O: C, 64.93; H, 4.29; N, 10.83. Found: C, 64.58; H, 4.51; N, 10.52.

Workup

  1. temperatureat reflux for 17 hours
  2. concentrationconcentrated in vacuo
  3. washwashed with water
  4. extractionThe aqueous layer was extracted with dichloromethane
  5. dry with materialthe combined organics dried over magnesium sulfate
  6. filtrationFiltration and concentration
  7. customfollowed by recrystallization of the residue from ethyl acetate-hexanes

Sources & evidence

ORD record
ord-a2bf1bbac54e4714812bb1089794abef
Source dataset
uspto-grants-2007_07
Patent number
US07244740B2

Reaction notes

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