Diisopropylethylamine → 2-Nitro-5-(oxetan-3-yl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine

HRID 1431182Notes

Reaction equation

HRID 1431182 reaction equation
Br[CH2:2][CH2:3][N:4]1[C:8]([CH2:9]Br)=[CH:7][C:6]([N+:11]([O-:13])=[O:12])=[N:5]1.[O:14]1[CH2:17][CH:16]([NH2:18])[CH2:15]1.C(N(C(C)C)CC)(C)C>C(#N)C>[N+:11]([C:6]1[CH:7]=[C:8]2[CH2:9][N:18]([CH:16]3[CH2:17][O:14][CH2:15]3)[CH2:2][CH2:3][N:4]2[N:5]=1)([O-:13])=[O:12]

Participants

5

Reactant 3

HCID 81531DiisopropylethylamineHCID 98339233-OxetanamineHCID 575020831-(2-bromoethyl)-5-(bromomethyl)-3-nitro-1H-pyrazole

Product 1

HCID 667429562-Nitro-5-(oxetan-3-yl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazineYield 71.1%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To a solution of 1-(2-bromoethyl)-5-(bromomethyl)-3-nitro-1H-pyrazole (500 mg, 1.6 mmol) in acetonitrile (20 mL) was added oxetan-3-amine (140 mg, 1.92 mmol) and diisopropylethyl amine (372 mg, 0.50 ml, 2.88 mmol) drop wise and the resulting mixture was stirred at room temperature for 24 h. The solution was concentrated and the residue dissolved in ethyl acetate (50 mL), washed with water (50 mL) and dried over magnesium sulfate. The resulting mixture was filtered and evaporated and the residue purified by flash chromatography (SF25-40 g, 50% to 100% ethyl acetate in hexanes) to give 2-nitro-5-oxetan-3-yl-4,5,6,7-tetrahydro-pyrazolo[1,5-a]pyrazine (255 mg, 71%) as a light yellow solid.

Workup

  1. concentrationThe solution was concentrated
  2. dissolutionthe residue dissolved in ethyl acetate (50 mL)
  3. washwashed with water (50 mL)
  4. dry with materialdried over magnesium sulfate
  5. filtrationThe resulting mixture was filtered
  6. customevaporated
  7. customthe residue purified by flash chromatography (SF25-40 g, 50% to 100% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-73bb196658a24c33b1ef41f938899d2e
Source dataset
uspto-grants-2015_01
Patent number
US08940741B2

Reaction notes

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