Tetrabutylammonium Fluoride → 2-bromo-5H-pyrrolo[2,3-b]pyrazine

HRID 2389018Notes

Reaction equation

HRID 2389018 reaction equation
[Br:1][C:2]1[N:3]=[C:4]([C:12]#[C:13][Si](C)(C)C)[C:5]([NH:8]C(=O)C)=[N:6][CH:7]=1.[F-].C([N+](CCCC)(CCCC)CCCC)CCC>C1COCC1>[Br:1][C:2]1[N:3]=[C:4]2[CH:12]=[CH:13][NH:8][C:5]2=[N:6][CH:7]=1

Participants

4

Reactant 2

HCID 2724141Tetrabutylammonium FluorideHCID 59836029N-(5-bromo-3-((trimethylsilyl)ethynyl)pyrazin-2-yl)acetamide

Product 1

HCID 250673082-bromo-5H-pyrrolo[2,3-b]pyrazineYield 43.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of N-(5-Bromo-3-trimethylsilanylethynyl-pyrazin-2-yl)-acetamide (474 mg, 1.52 mmol) in THF (4 ml) was added dropwise a 1 M solution of tetra-n-butyl ammonium fluoride in THF (3.3 ml, 3.3 mmol). After stirring at reflux for 15 hours, the reaction mixture was concentrated in vacuum and water added. The aqueous layer was extracted three times with dichloromethane and the combined extracts were directly adsorbed on silica gel. Purification by silica gel chromatography with a gradient of ethyl acetate/hexanes afforded the title compound (130 mg, 43% yield) as a yellow solid. 1H-NMR (500 MHz, d6-DMSO) δ 12.38 (s br, 1H), 8.38 (s, 1H), 7.95 (d, 3.5 Hz, 1H), 6.61 (d, 3.5 Hz, 1H). MS: m/z 197.9/199.9 [MH+].

Workup

  1. temperatureat reflux for 15 hours
  2. concentrationthe reaction mixture was concentrated in vacuum and water
  3. additionadded
  4. extractionThe aqueous layer was extracted three times with dichloromethane
  5. customPurification by silica gel chromatography with a gradient of ethyl acetate/hexanes

Sources & evidence

ORD record
ord-033edc94de9342c489ab90709993b2b6
Source dataset
uspto-grants-2012_09
Patent number
US08268994B2

Reaction notes

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