Trimethylsilylacetylene → Ethyl 6-[(trimethylsilyl)ethynyl]imidazo[1,2-a]pyridine-2-carboxylate

HRID 2363752Notes

Reaction equation

HRID 2363752 reaction equation
I[C:2]1[CH:3]=[CH:4][C:5]2[N:6]([CH:8]=[C:9]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[N:10]=2)[CH:7]=1.[C:16]([Si:18]([CH3:21])([CH3:20])[CH3:19])#[CH:17]>Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[CH3:19][Si:18]([C:16]#[C:17][C:2]1[CH:3]=[CH:4][C:5]2[N:6]([CH:8]=[C:9]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[N:10]=2)[CH:7]=1)([CH3:21])[CH3:20]

Participants

4

Reactant 2

HCID 66111TrimethylsilylacetyleneHCID 3681971Ethyl 6-iodoimidazo[1,2-a]pyridine-2-carboxylate

Product 1

HCID 44136341Ethyl 6-[(trimethylsilyl)ethynyl]imidazo[1,2-a]pyridine-2-carboxylate

Reagents, catalysts & solvents 1

HCID 178418476HCID 178418476, compoundCatalyst

Conditions

Temperature
50 °C

Procedure

A mixture of 4 g of ethyl 6-iodoimidazo[1,2-a]pyridine-2-carboxylate, 2.63 mL of ethynyltrimethylsilane and 888 mg of dichlorobis(triphenylphosphine)palladium is degassed under vacuum. 240 mg of degassed N,N-dimethylformamide and 3.52 mL of triethylamine are added. The reaction mixture is degassed under argon, stirred at 50° C. for 50 hours and then cooled and diluted with 20 mL of water. The precipitate is filtered off by suction and washed with 5 mL of water and then chromatographed on silica, eluting with mixtures of ethyl acetate and hexane (from 50/50 to 90/10). The fractions containing the expected product are combined and concentrated to dryness under reduced pressure to give 3.6 g of ethyl 6-[(trimethylsilyl)ethynyl]imidazo[1,2-a]pyridine-2-carboxylate in the form of an off-white solid.

Workup

  1. customis degassed under vacuum
  2. addition240 mg of degassed N,N-dimethylformamide and 3.52 mL of triethylamine are added
  3. customThe reaction mixture is degassed under argon
  4. temperaturecooled
  5. additiondiluted with 20 mL of water
  6. filtrationThe precipitate is filtered off by suction
  7. washwashed with 5 mL of water
  8. customchromatographed on silica
  9. washeluting with mixtures of ethyl acetate and hexane (from 50/50 to 90/10)
  10. additionThe fractions containing the expected product
  11. concentrationconcentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-ca67b75e54e749fc82854ca95a158990
Source dataset
uspto-grants-2014_04
Patent number
US08691990B2

Reaction notes

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