反应详情

To a solution of N-tert-butyloxycarbonyl-(S)-phenylalanine dimethylamide (Preparation 7, 24.8 g, 84 mmol) in methanol (50 mL) was added a solution of hydrochloric acid (4N, in dioxane, 40 mL) and the mixture stirred at rt for 3 h. The resulting solution was concentrated in vacuo then dissolved in water (300 mL). The aqueous solution was washed with ethyl acetate (3×100 mL) and concentrated again. Successive recrystallisations with methanol (200 mL) and a mixture of methanol and toluene (1:1, 200 mL) gave the title compound as colourless crystals. δH (D2O) 2.75, 2.90 (6H, 2×s), 3.18 (2H, m), 4.72 (1H, t), 7.28–7.45 (5H, m).

1. concentrationThe resulting solution was concentrated in vacuo
2. dissolutionthen dissolved in water (300 mL)
3. washThe aqueous solution was washed with ethyl acetate (3×100 mL)
4. concentrationconcentrated again
5. customSuccessive recrystallisations with methanol (200 mL)
6. additiona mixture of methanol and toluene (1:1, 200 mL)