反应详情

Nitropropane (0.475 mL, 5.29 mmol) and phenylisocyanate (1.0 mL, 9.5 mmol) were dissolved in benzene (10 mL) and added to a flask containing 7a-ethynyl-hexahydro-1H-pyrrolizine (358 mg, 2.65 mmol, from step 13a). The solution was stirred at ambient temperature for 1 hour and at reflux for 5 hours. The mixture was cooled, filtered, concentrated and diluted with EtOAc. The solution was extracted with 6N HCl. The aqueous phase was made basic with 15% NaOH and extracted with methylene chloride. The organic extracts were combined, dried (MgSO4) and concentrated. The residue was residue was chromatographed (silica gel; CHCl3 /MeOH, 98:2) to afford an amber oil (274 mg, 50%). 1H NMR (CDCl3, 300 MHz) δ1.25 (t, J=7.5 Hz, 3H), 1.75-1.92 (m, 6H), 2.15-2.25 (m, 2H), 2.60-2.69 (m, 4H), 3.13-3.20 (m, 2H), 5.98 (s, 1H); MS (CI/NH3) m/z: 207 (M+H)+.

1. additionadded to a flask
2. temperatureat reflux for 5 hours
3. temperatureThe mixture was cooled
4. filtrationfiltered
5. concentrationconcentrated
6. additiondiluted with EtOAc
7. extractionThe solution was extracted with 6N HCl
8. extractionextracted with methylene chloride
9. dry with materialdried (MgSO4)
10. concentrationconcentrated
11. customwas chromatographed (silica gel; CHCl3 /MeOH, 98:2)