反应详情

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).

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)