Hydrochloric Acid → 2-(3-nitro-1H-pyrazol-1-yl)ethanol

HRID 2365711Notes

Reaction equation

HRID 2365711 reaction equation
C([Si](C)(C)[O:6][CH2:7][CH2:8][N:9]1[CH:13]=[CH:12][C:11]([N+:14]([O-:16])=[O:15])=[N:10]1)(C)(C)C.Cl>C(O)C.Cl>[N+:14]([C:11]1[CH:12]=[CH:13][N:9]([CH2:8][CH2:7][OH:6])[N:10]=1)([O-:16])=[O:15]

Participants

5

Reactant 2

HCID 313Hydrochloric AcidHCID 593449511-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole

Product 1

HCID 163948492-(3-nitro-1H-pyrazol-1-yl)ethanolYield 94%

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidCatalystHCID 702EthanolSolvent

Procedure

A solution of 1-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole (prepared as in US 20080021032 Example 67, 6.34 g, 23.36 mmol) in ethanol (100 mL) was treated with concentrated hydrochloric acid (12 drops) and stirred for 1 h at room temperature. After this time, another portion of concentrated hydrochloric acid was added (12 drops) and it was stirred overnight at room temperature. After this time, the reaction mixture was concentrated in vacuo and then azeotroped with acetonitrile. The crude material was then purified by flash column chromatography (silica gel 60, 230-400 mesh, 80% ethyl acetate/hexanes) to afford 2-(3-nitro-pyrazol-1-yl)-ethanol (2.36 g, 94%) as a white solid: 1H NMR (300 MHz, DMSO-d6) δ ppm 8.00 (d, J=2.56 Hz, 1H), 7.03 (d, J=2.56 Hz, 1H), 5.00 (t, J=5.31 Hz, 1H), 4.26 (t, J=5.31 Hz, 2H), 3.77 (q, J=5.49 Hz, 2H).

Workup

  1. stirringwas stirred overnight at room temperature
  2. concentrationAfter this time, the reaction mixture was concentrated in vacuo
  3. customazeotroped with acetonitrile
  4. customThe crude material was then purified by flash column chromatography (silica gel 60, 230-400 mesh, 80% ethyl acetate/hexanes)

Sources & evidence

ORD record
ord-e70fab388c624101ba2cc0a9c566ae3a
Source dataset
uspto-grants-2014_04
Patent number
US08697705B2

Reaction notes

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