Dimethylformamide → 1-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole

HRID 1772132Notes

Reaction equation

HRID 1772132 reaction equation
[N+:1]([C:4]1[CH:8]=[CH:7][NH:6][N:5]=1)([O-:3])=[O:2].[Si:9]([O:16][CH2:17][CH2:18]Br)([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10].C(=O)([O-])[O-].[Cs+].[Cs+].CN(C=O)C>C(Cl)Cl.O>[Si:9]([O:16][CH2:17][CH2:18][N:6]1[CH:7]=[CH:8][C:4]([N+:1]([O-:3])=[O:2])=[N:5]1)([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10]

Participants

7

Reactant 4

HCID 6228DimethylformamideHCID 10796Cesium carbonateHCID 3608067(2-Bromoethoxy)-tert-butyldimethylsilaneHCID 178526745HCID 178526745, compound

Product 1

HCID 593449511-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazoleYield 85%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
70 °C

Procedure

A 100-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer was purged with nitrogen and charged with 3-nitro-1H-pyrazole (500 mg, 4.42 mmol), 2-(tert-butyldimethylsilyloxy)-1-bromoethane (2.12 g, 8.85 mmol), cesium carbonate (5.76 g, 17.7 mmol) and anhydrous DMF (5 mL). After heating at 70° C. for 1 h, the mixture was cooled to room temperature and diluted with methylene chloride (50 mL) and water (30 mL). The organic layer was separated, and the aqueous layer was extracted with methylene chloride (2×30 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography to afford an 85% yield (1.02 g) of 119a as a white solid: mp 76-77° C.; 1H NMR (500 MHz, CDCl3) δ 7.52 (d, 1H, J=2.5 Hz), 6.87 (d, 1H, J=2.5 Hz), 4.29 (t, 2H, J=5.0 Hz), 3.98 (t, 2H, J=5.0 Hz), 0.84 (s, 9H), −0.44 (s, 6H).

Workup

  1. customA 100-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer
  2. customwas purged with nitrogen
  3. temperaturethe mixture was cooled to room temperature
  4. customThe organic layer was separated
  5. extractionthe aqueous layer was extracted with methylene chloride (2×30 mL)
  6. dry with materialThe combined organic layers were dried over sodium sulfate
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified by column chromatography

Sources & evidence

ORD record
ord-ae96e02384cd409690ac04cd608c9a90
Source dataset
uspto-grants-2016_02
Patent number
US09249123B2

Reaction notes

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