反应详情

To a suspension of 80% sodium hydride (2.48 g, 83 mmol) in benzene (50 ml) was slowly added a solution of methyl 2- ethoxycarbonylamino- 3,3-diphenylpropanoate (Example 1b, 27.0 g, 83 mmol) in benzene (200 ml) and the mixture then heated at reflux for 1 h. Ethanol (1.0 ml) followed by ethyl acrylate (8.95 ml, 83 mmol) were added and the reaction heated at reflux for 2 h, the solvent was then distilled off and the residue allowed to cool to room temperature. A solution of the residue in water was added to a concentrated sulphuric acid/ice mixture and the product extracted into ethyl acetate. The organic phase was washed with saturated brine and dried (MgSO4). The residue was chromatographed on silica gel in dichloromethane/methanol (97:3) to give 1,4-bis(ethoxycarbonyl)-2-(diphenylmethyl)-pyrrolidin-3-one, m/z (CI+) 396(MH). A solution of this oil in 1.0M oxalic acid was heated at reflux for 8 h, cooled and the product extracted into chloroform. After separation the chloroform was removed in vacuo and the residue chromatographed on silica gel using ethyl acetate/hexane (1:4) as eluant to give 2-(diphenylmethyl)-1-ethoxycarbonylpyrrolidin-3 -one. 1H NMR (250 MHz, CDCl3) δ7.14-7.52 (10H, m), 4.80 (1H, br s), 4.68 (1H, vbr s), 4.18 (2H, br q), 3.94 (1H, vbs), 3.06 (1H, m), 2.34 (1H, m), 1.76 (1H, m), 1.22 (3H, t, J=7.0 Hz). m/z (CI+) 324(MH).

1. temperaturethe mixture then heated
2. temperatureat reflux for 1 h
3. additionwere added
4. temperaturethe reaction heated
5. temperatureat reflux for 2 h
6. distillationthe solvent was then distilled off
7. additionA solution of the residue in water was added to a concentrated sulphuric acid/ice mixture
8. extractionthe product extracted into ethyl acetate
9. washThe organic phase was washed with saturated brine
10. dry with materialdried (MgSO4)
11. customThe residue was chromatographed on silica gel in dichloromethane/methanol (97:3)