反应详情

温度

25 °C

A stirred solution of (S)-N-BOC diethyl Laspartate 3 (47.41 g, 0.16 mol) in absolute ethanol (770 ml) was cooled in ice, then sodium borohydride (60.8 g, 1.6 mol) was added in 10 g portions. The cooling bath was removed when the reaction subsided, and the reaction mixture was heated slowly to reflux for 1 h; after this time TLC (EtOAc-EtOH 3:1) analysis indicated complete consumption of the starting material. The reaction mixture was cooled to 25° C., and the lumps formed were broken-up to give a slurry that was poured into brine (450 ml). The mixture was filtered, the filtrate concentrated in vacuum to ca. 100 ml, and was extracted with ether (6×300 ml). The insoluble solid material was extracted by stirring in ether (4×1 L) for 2 h. The combined ether extracts were dried over MgSO4, filtered and concentrated to give 4 as a colourless oil (24 g, 73%), which crystallised on standing. Spectral data for this sample were consistent with those given in the literature2. 1H NMR (200 MHz, d6-DMSO) 6.45 (d, J=8.4 Hz, 1H), 4.57 (t,J=5.6 Hz, 1H), 4.35 (t,J=5.1 Hz, 1H), 3.40 (m, 4H), 3.23 (m, 1H), 1.62 (m, 1H), 1.40 (m, 1H), 1.36 (s, 9H); 13C NMR (50 MHz, d6-DMSO) 155.5, 77.4, 63.5, 58.0, 49.6, 34.4, 2.83.

1. customThe cooling bath was removed when the reaction
2. temperaturethe reaction mixture was heated slowly
3. temperatureto reflux for 1 h
4. customconsumption of the starting material
5. customthe lumps formed
6. customto give a slurry that
7. filtrationThe mixture was filtered
8. concentrationthe filtrate concentrated in vacuum to ca. 100 ml
9. extractionwas extracted with ether (6×300 ml)
10. extractionThe insoluble solid material was extracted
11. dry with materialThe combined ether extracts were dried over MgSO4
12. filtrationfiltered
13. concentrationconcentrated