反应详情

To a mixture of β-alanine ethyl ester hydrochloride (2.69 g, 17.5 mmol), benzaldehyde (1.68 mL, 16.6 mmol) and sodium sulfate in DCM (30 mL) was added diisopropylethylamine (3.35 mL, 19.3 mmol) and the resulting mixture stirred at ambient temperature for 4 hours. The reaction mixture was filtered and the filtrate concentrated under vacuum to a clear oil. The oil was re-dissolved in methanol (30 mL) and cooled to 0° C., and then sodium borohydride (662 mg, 17.5 mmol) was added. The resulting mixture was warmed to ambient temperature and stirred for 16 hours. The reaction mixture was concentrated under vacuum and the resulting residue dissolved in DCM and washed with 10% aqueous citric acid, then dried over sodium sulfate and concentrated under vacuum to afford 2.45 g (71%) of 3-benzylamino-propionic acid ethyl ester as a clear oil. LCMS (Method I, ESI): RT=1.49 and 0.31 min, m+H=208.3; 1H NMR (400 MHz, CDCl3) δ: 7.32 (s, 3H), 7.25 (m, 2H), 4.14 (q, 2H), 3.68 (s, 2H), 2.90 (t, 2H), 2.55 (m, 2H), 1.25 (t, 3H).

1. filtrationThe reaction mixture was filtered
2. concentrationthe filtrate concentrated under vacuum to a clear oil
3. dissolutionThe oil was re-dissolved in methanol (30 mL)
4. temperaturecooled to 0° C.
5. temperatureThe resulting mixture was warmed to ambient temperature
6. stirringstirred for 16 hours
7. concentrationThe reaction mixture was concentrated under vacuum
8. dissolutionthe resulting residue dissolved in DCM
9. washwashed with 10% aqueous citric acid
10. dry with materialdried over sodium sulfate
11. concentrationconcentrated under vacuum