反应详情

(±)-(4R*,5R*)-5-(Ethoxycarbonyl)-1-methyl-4-phenylpyrrolidin-2-one (16 g, 64.8 mmol), prepared according to the method of W. Hartwig and L. Born, J. Org. Chem., 52, 4352 (1987), was heated at the reflux temperature overnight in a 3:1 mixture of 3M HCl solution and water. The resulting mixture was allowed to cool to room temperature, extracted with EtOAc, dried (Na2SO4) and concentrated under reduced pressure. The crude product was triturated (Et2O) to give (±)-(4R*,5R*)-5-carboxy-1-methyl-4-phenylpyrrolidin-2-one (9.5 g, 67%): 1H NMR (CDCl3) δ 2.60 (dd, J=8.3, 16.0 Hz, 1H), 2.82-2.91 (m, 4H), 3.90 (q, J=8.9 Hz, 1H), 3.95 (br s, 1H), 4.37 (d, J=8.6 Hz, 1H), 7.19-7.32 (m, 5H).

1. extractionextracted with EtOAc
2. dry with materialdried (Na2SO4)
3. concentrationconcentrated under reduced pressure
4. customThe crude product was triturated (Et2O)