Water → Ethyl 6-ethynylimidazo[1,2-a]pyridine-2-carboxylate

HRID 2363753Notes

Reaction equation

HRID 2363753 reaction equation
C[Si]([C:5]#[C:6][C:7]1[CH:8]=[CH:9][C:10]2[N:11]([CH:13]=[C:14]([C:16]([O:18][CH2:19][CH3:20])=[O:17])[N:15]=2)[CH:12]=1)(C)C.[F-].C([N+](CCCC)(CCCC)CCCC)CCC.O>O1CCCC1>[C:6]([C:7]1[CH:8]=[CH:9][C:10]2[N:11]([CH:13]=[C:14]([C:16]([O:18][CH2:19][CH3:20])=[O:17])[N:15]=2)[CH:12]=1)#[CH:5]

Participants

5

Reactant 3

HCID 962WaterHCID 2724141Tetrabutylammonium FluorideHCID 44136341Ethyl 6-[(trimethylsilyl)ethynyl]imidazo[1,2-a]pyridine-2-carboxylate

Product 1

HCID 44136342Ethyl 6-ethynylimidazo[1,2-a]pyridine-2-carboxylateYield 74.9%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of 500 mg of ethyl 6-[(trimethylsilyl)ethynyl]imidazo[1,2-a]pyridine-2-carboxylate in 10 mL of anhydrous tetrahydrofuran, cooled to 0° C. are added dropwise 1.58 mL of a 1M solution of tetrabutylammonium fluoride in tetrahydrofuran. The reaction mixture is stirred for 30 minutes, 5 mL of water are then added and the resulting mixture is extracted three times with 20 mL of dichloromethane. The product is purified by chromatography on silica, eluting with mixtures of ethyl acetate and hexane (from 1/3 to 1/1). The fractions containing the expected product are combined and concentrated to dryness under reduced pressure to give 280 mg of ethyl 6-ethynylimidazo[1,2-a]pyridine-2-carboxylate in the form of a yellow solid.

Workup

  1. extractionthe resulting mixture is extracted three times with 20 mL of dichloromethane
  2. customThe product is purified by chromatography on silica
  3. washeluting with mixtures of ethyl acetate and hexane (from 1/3 to 1/1)
  4. additionThe fractions containing the expected product
  5. concentrationconcentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-66a03d95a62d48b480bb900f346c5f91
Source dataset
uspto-grants-2014_04
Patent number
US08691990B2

Reaction notes

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