m-Chloroperbenzoic acid → 5-(4,8-Dioxabicyclo[5.1.0]octan-5-yl)-1-methyl-4-nitro-pyrazole

HRID 521845Notes

Reaction equation

HRID 521845 reaction equation
[CH2:1]([O:4][CH:5]([C:10]1[N:14]([CH3:15])[N:13]=[CH:12][C:11]=1[N+:16]([O-:18])=[O:17])[CH2:6][CH2:7][CH:8]=[CH2:9])C=C.CN1C(C2CCCC=C[O:26]2)=C([N+]([O-])=O)C=N1.C1C=C(Cl)C=C(C(OO)=O)C=1>C(Cl)Cl.Cl[Ru](=C1N(C2C(C)=CC(C)=CC=2C)CCN1C1C(C)=CC(C)=CC=1C)(Cl)(=CC1C=CC=CC=1)[P](C1CCCCC1)(C1CCCCC1)C1CCCCC1>[CH:8]12[O:26][CH:7]1[CH2:6][CH:5]([C:10]1[N:14]([CH3:15])[N:13]=[CH:12][C:11]=1[N+:16]([O-:18])=[O:17])[O:4][CH2:1][CH2:9]2

Participants

6

Reactant 3

HCID 70297m-Chloroperbenzoic acidHCID 867137765-(1-Allyloxypent-4-enyl)-1-methyl-4-nitro-pyrazoleHCID 867137891-Methyl-4-nitro-5-(tetrahydrooxepin-2-yl)pyrazole

Product 1

HCID 867137885-(4,8-Dioxabicyclo[5.1.0]octan-5-yl)-1-methyl-4-nitro-pyrazole

Reagents, catalysts & solvents 2

HCID 178425456HCID 178425456, compoundCatalystHCID 6344DichloromethaneSolvent3×

Conditions

Temperature
40 °C

Procedure

5-(1-Allyloxypent-4-enyl)-1-methyl-4-nitro-pyrazole (7.08 g, 28.2 mmol) was dissolved in DCM (910 mL) and the mixture degassed for 30 min before Grubbs 2nd generation catalyst (1.19 g, 1.41 mmol) was added. The reaction mixture was heated at 40° C. for 18 hr and concentrated under reduced pressure. Purification via silica gel column chromatography (0-10% EtOAc/isohexane) followed by reverse-phase preparative HPLC gave a mixture of isomers of 1-methyl-4-nitro-5-(tetrahydrooxepin-2-yl)pyrazole (66/34) as a clear oil (2.3 g). To a solution of this oil (2.3 g, 10.31 mmol) in DCM (50 mL) was added m-CPBA (70-75%, 3.56 g, 14.40 mmol) and the reaction mixture was stirred at room temperature for 4 hr. The reaction mixture was diluted with DCM (50 mL) and the organic layer was washed with saturated aqueous NaHCO3 (2×50 mL), water (50 mL) and brine (50 mL), dried over MgSO4, and concentrated under reduced pressure. Purification via silica gel column chromatography (0-30% EtOAc/isohexane) gave 5-(4,8-dioxabicyclo[5.1.0]octan-5-yl)-1-methyl-4-nitro-pyrazole as a colourless solid (1.0 g, 14% over two steps). 1H NMR (400 MHz, CDCl3) δ 8.02 (s, 1H), 5.51-5.44 (m, 1H), 4.02 (s, 3H), 3.93 (dt, J=12.7, 3.4 Hz, 1H), 3.62-3.53 (m, 1H), 3.35-3.27 (m, 2H), 2.58-2.51 (m, 1H), 2.41-2.25 (m, 3H).

Workup

  1. additionwas added
  2. concentrationconcentrated under reduced pressure
  3. customPurification via silica gel column chromatography (0-10% EtOAc/isohexane)
  4. customgave
  5. washthe organic layer was washed with saturated aqueous NaHCO3 (2×50 mL), water (50 mL) and brine (50 mL)
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated under reduced pressure
  8. customPurification via silica gel column chromatography (0-30% EtOAc/isohexane)

Sources & evidence

ORD record
ord-9d49a6f247694cf78cd35a1cdd191073
Source dataset
uspto-grants-2016_05
Patent number
US09328106B2

Reaction notes

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