Potassium Carbonate → 1-(5-Ethynylpyridin-2-yl)-4-methylpiperazine

HRID 447301Notes

Reaction equation

HRID 447301 reaction equation
C(=O)([O-])[O-].[K+].[K+].[CH3:7][N:8]1[CH2:13][CH2:12][N:11]([C:14]2[CH:19]=[CH:18][C:17]([C:20]#[C:21][Si](C)(C)C)=[CH:16][N:15]=2)[CH2:10][CH2:9]1>CO>[C:20]([C:17]1[CH:18]=[CH:19][C:14]([N:11]2[CH2:12][CH2:13][N:8]([CH3:7])[CH2:9][CH2:10]2)=[N:15][CH:16]=1)#[CH:21]

Participants

4

Reactant 2

HCID 11430Potassium CarbonateHCID 667304181-Methyl-4-(5-((trimethylsilyl)ethynyl)pyridin-2-yl)piperazine

Product 1

HCID 866588281-(5-Ethynylpyridin-2-yl)-4-methylpiperazineYield 99.8%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Potassium carbonate (1M aq., 1.5 mL, 1.5 mmol) was added in a drop-wise manner to a solution of 1-methyl-4-(5-((trimethylsilyl)ethynyl)pyridin-2-yl)piperazine (325 mg, 1.19 mmol) in MeOH (5.0 mL) at room temperature, and the resulting mixture was stirred for 2 h. After removal of the solvent in vacuo, water (5 mL) and brine (10 mL) were added and the product was extracted with DCM (150 mL, then 3×10 mL). The combined organic layers were washed with brine (15 mL), dried over Na2SO4 and filtered. Evaporation of the solvent gave 1-(5-ethynylpyridin-2-yl)-4-methylpiperazine (239 mg, quantitative yield), which was used in the next step without purification. 1H NMR (400 MHz, CDCl3) δ ppm 8.32 (s, 1H), 7.55 (dd, J=8.9, 2.1 Hz, 1H), 6.58 (d, J=8.8 Hz, 1H), 3.54-3.67 (m, 4H), 3.08 (s, 1H), 2.46-2.58 (m, 4H), 2.35 (s, 3H); MS ESI [M+H]+ 201.9, calcd for [C12H15N3+H]+ 202.1.

Workup

  1. customAfter removal of the solvent in vacuo, water (5 mL) and brine (10 mL)
  2. additionwere added
  3. extractionthe product was extracted with DCM (150 mL
  4. washThe combined organic layers were washed with brine (15 mL)
  5. dry with materialdried over Na2SO4
  6. filtrationfiltered
  7. customEvaporation of the solvent

Sources & evidence

ORD record
ord-34bf4763863a4b18ac4a3a2f2d5e2083
Source dataset
uspto-grants-2013_07
Patent number
US08481533B2

Reaction notes

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