反应详情

3-Amino-2-tert-butoxycarbonylamino-propionic acid (5.0 g, 24.5 mmol) was suspended in methanol (100 mL) and benzaldehyde (5.2 g, 49 mmol) was added, followed by triethylamine (TEA, 10.2 mL, 73.5 mmol). The reaction mixture was stirred at ambient temperature for 90 minutes and cooled to 0° C. Solid sodium borohydride (2.78 g, 73.5 mmol) was added in small portions and the reaction was stirred for additional 60 minutes after addition was complete. All volatiles were removed in vacuo and the crude was dissolved in NaOH aq (0.1 M, 100 mL). The solution was washed with diethyl ether and acidified with HCl aq. The mixture was extracted with chloroform. The organic extracts were washed with brine and dried over sodium sulfate. Filtration and evaporation of solvents in vacuo yielded crude semi-solid (9.0 g). The crude material was dissolved in methanol (40 mL) and toluene (20 mL) and the solution was cooled to 0° C. Trimethysilyl diazomethane solution (2M, in hexanes) was added until the yellow color persisted (˜25 mL). The reaction mixture was stirred for additional 60 minutes at room temperature. The volatiles were removed in vacuo and the crude product was purified via silica gel chromatography (eluent: EtOAc/hexanes) to yield the pure product 3-Benzylamino-2-tert-butoxycarbonylamino-propionic acid methyl ester (4.09 g): LCMS-ESI+: calc'd for C16H24N2O4: 308.3 (M+). Found: 309.2 (M+H+).

1. temperaturecooled to 0° C
2. stirringthe reaction was stirred for additional 60 minutes
3. additionafter addition
4. customAll volatiles were removed in vacuo
5. dissolutionthe crude was dissolved in NaOH aq (0.1 M, 100 mL)
6. washThe solution was washed with diethyl ether
7. extractionwas extracted with chloroform
8. washThe organic extracts were washed with brine
9. dry with materialdried over sodium sulfate
10. filtrationFiltration and evaporation of solvents in vacuo
11. customyielded crude semi-solid (9.0 g)
12. stirringThe reaction mixture was stirred for additional 60 minutes at room temperature
13. customThe volatiles were removed in vacuo
14. customthe crude product was purified via silica gel chromatography (eluent: EtOAc/hexanes)