Aniline → 6-bromo-N-phenylimidazo[1,2-a]pyridine-2-carboxamide

HRID 2363721Notes

Reaction equation

HRID 2363721 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C[Al](C)C.[Br:12][C:13]1[CH:14]=[CH:15][C:16]2[N:17]([CH:19]=[C:20]([C:22](OCC)=[O:23])[N:21]=2)[CH:18]=1.[Cl-].[NH4+]>C1(C)C=CC=CC=1>[Br:12][C:13]1[CH:14]=[CH:15][C:16]2[N:17]([CH:19]=[C:20]([C:22]([NH:1][C:2]3[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=3)=[O:23])[N:21]=2)[CH:18]=1

Participants

6

Reactant 4

HCID 6115AnilineHCID 25517Ammonium ChlorideHCID 7141939Ethyl 6-bromoimidazo[1,2-a]pyridine-2-carboxylateHCID 16682925Trimethylaluminum

Product 1

HCID 247716736-bromo-N-phenylimidazo[1,2-a]pyridine-2-carboxamideYield 69.9%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Procedure

To a solution of 3 g of aniline in 366 mL of toluene cooled to 0° C. are added dropwise 22.5 mL of a 2M solution of trimethylaluminium in toluene, followed by addition, at 20° C., of 5.6 g of ethyl 6-bromoimidazo[1,2-a]pyridine-2-carboxylate. The reaction mixture is stirred for 2 hours at room temperature. The resulting mixture is cooled to 4° C. and 150 mL of saturated ammonium chloride solution are then added. The reaction mixture is concentrated to dryness and is then taken up in 400 mL of water and 400 mL of dichloromethane. The organic phase is dried over magnesium sulfate, filtered through Celite and evaporated to dryness under reduced pressure to give 4.6 g of 6-bromo-N-phenylimidazo[1,2-a]pyridine-2-carboxamide in the form of an off-white powder.

Workup

  1. temperatureThe resulting mixture is cooled to 4° C.
  2. concentrationThe reaction mixture is concentrated to dryness
  3. dry with materialThe organic phase is dried over magnesium sulfate
  4. filtrationfiltered through Celite
  5. customevaporated to dryness under reduced pressure

Sources & evidence

ORD record
ord-ad8fa5e1052e42c1854857e7ac0ab5f5
Source dataset
uspto-grants-2014_04
Patent number
US08691990B2

Reaction notes

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