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

HRID 2381280Notes

Reaction equation

HRID 2381280 reaction equation
[N+:1]([C:4]1[CH:8]=[CH:7][NH:6][N:5]=1)([O-:3])=[O:2].[H-].[Na+].Br[CH2:12][CH2:13][O:14][Si:15]([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16]>CN(C)C=O.C(OCC)(=O)C>[C:18]([Si:15]([CH3:17])([CH3:16])[O:14][CH2:13][CH2:12][N:6]1[CH:7]=[CH:8][C:4]([N+:1]([O-:3])=[O:2])=[N:5]1)([CH3:21])([CH3:20])[CH3:19]

Participants

6

Reactant 3

HCID 24758Sodium hydrideHCID 3608067(2-Bromoethoxy)-tert-butyldimethylsilaneHCID 178526745HCID 178526745, compound2×

Product 1

HCID 593449511-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazoleYield 84.7%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Procedure

A solution of 3-nitro-1H-pyrazole (Intermediate 2, 250 mg, 2.21 mmol) was dissolved in anhydrous N,N-dimethylformamide (5 mL) was treated with a 60% dispersion of sodium hydride in mineral oil (93 mg, 2.32 mmol) was added while stirring under nitrogen. After the effervescence ceased, the reaction stirred for an additional 10 min. At this time, the reaction was treated with (2-bromo-ethoxy)-tert-butyl-dimethyl-silane (598 mg, 2.50 mmol). The reaction continued to stir under nitrogen for 2 h. At this time, the solution was diluted with ethyl acetate (200 mL), washed with water (2×75 mL), a saturated aqueous sodium chloride solution (75 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (Merck silica gel 60, 40-63 μm; 5-25% ethyl acetate/hexanes) afforded 1-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole (508 mg, 84%) as a yellow oil. 1H-NMR (400 MHz, DMSO-d6) δ 0.00 (6H, s), 0.86 (9H, s), 4.03 (2H, t, J=5.6 Hz), 4.40 (2H, t, J=5.2 Hz), 7.11 (1H, d, J=2.4 Hz), 8.06 (1H, d, J=2.4 Hz).

Workup

  1. additionwas added
  2. stirringthe reaction stirred for an additional 10 min
  3. stirringto stir under nitrogen for 2 h
  4. washwashed with water (2×75 mL)
  5. dry with materiala saturated aqueous sodium chloride solution (75 mL), dried over magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-45b11499afa14f048ef6e02bbe2292b2
Source dataset
uspto-grants-2012_09
Patent number
US08258134B2

Reaction notes

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