5-(1-Allyloxypent-4-enyl)-1-methyl-4-nitro-pyrazole → 1-Methyl-4-nitro-5-(2,3,4,7-tetrahydrooxepin-2-yl)pyrazole

HRID 521835Notes

Reaction equation

HRID 521835 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>C1(C)C=CC=CC=1>[CH3:15][N:14]1[C:10]([CH:5]2[CH2:6][CH2:7][CH:8]=[CH:9][CH2:1][O:4]2)=[C:11]([N+:16]([O-:18])=[O:17])[CH:12]=[N:13]1

Participants

3

Reactant 1

HCID 867137765-(1-Allyloxypent-4-enyl)-1-methyl-4-nitro-pyrazole

Product 1

HCID 867137771-Methyl-4-nitro-5-(2,3,4,7-tetrahydrooxepin-2-yl)pyrazoleYield 75%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

5-(1-Allyloxypent-4-enyl)-1-methyl-4-nitro-pyrazole (5 g, 19.92 mmol) was dissolved in toluene (1 L) and the mixture was degassed for 30 min before Benzylidene-bis(tricyclohexylphosphine)dichlororuthenium, Bis(tricyclohexylphosphine)benzylidine ruthenium(IV) dichloride, “Grubbs 1st generation catalyst” CAS No. 172222-30-9, Sigma-Aldrich Product No. 579726, U.S. Pat. No. 6,111,121, (878 mg, 0.99 mmol) was added. The reaction mixture was further degassed for 20 min, then heated at reflux for 2 hr, cooled to room temperature and filtered through Celite®. The filtrate was concentrated under reduced pressure. The residue was dissolved in EtOAc (200 mL), washed with aqueous 1 M HCl (150 mL), water (150 mL), saturated aqueous NaHCO3 (2×150 mL) and brine (150 mL). The organic layer was separated, dried over MgSO4 and concentrated under reduced pressure. Purification via silica gel column chromatography (0-20% EtOAc/isohexane) gave 1-methyl-4-nitro-5-(2,3,4,7-tetrahydrooxepin-2-yl)pyrazole as a clear oil (3.3 g, 75%). 1H NMR (400 MHz, CDCl3) δ 8.02 (s, 1H), 5.99-5.91 (m, 1H), 5.83-5.76 (m, 1H), 5.59 (dd, J=9.4, 3.0 Hz, 1H), 4.42 (dd, J=15.8, 5.5 Hz, 1H), 4.24-4.17 (m, 1H), 4.06 (s, 3H), 2.58-2.48 (m, 1H), 2.46-2.36 (m, 1H), 2.14 (ddt, J=14.1, 6.8, 3.5 Hz, 1H), 1.99-1.88 (m, 1H).

Workup

  1. customthe mixture was degassed for 30 min before Benzylidene-bis(tricyclohexylphosphine)dichlororuthenium, Bis(tricyclohexylphosphine)benzylidine ruthenium(IV) dichloride, “Grubbs 1st generation catalyst” CAS No
  2. addition6,111,121, (878 mg, 0.99 mmol) was added
  3. customThe reaction mixture was further degassed for 20 min
  4. temperatureheated
  5. temperatureat reflux for 2 hr
  6. filtrationfiltered through Celite®
  7. concentrationThe filtrate was concentrated under reduced pressure
  8. dissolutionThe residue was dissolved in EtOAc (200 mL)
  9. washwashed with aqueous 1 M HCl (150 mL), water (150 mL), saturated aqueous NaHCO3 (2×150 mL) and brine (150 mL)
  10. customThe organic layer was separated
  11. dry with materialdried over MgSO4
  12. concentrationconcentrated under reduced pressure
  13. customPurification via silica gel column chromatography (0-20% EtOAc/isohexane)

Sources & evidence

ORD record
ord-9793071a80bf4b7bbea3df9337da03ed
Source dataset
uspto-grants-2016_05
Patent number
US09328106B2

Reaction notes

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