反应详情

A 1 L, 3-neck flask was equipped with two dropping funnels, one containing 21.3 mL of 2.0 N H2SO4 and the other containing 21.3 mL of 2.0 N NaNO2. A mixture of 5.00 g (38.7 mmol) of 2-(S)amino-3-(cyclopropyl)propanoic acid in 28 mL of H2O at 0° C. was treated with a sufficient amount of the acid solution to dissolve the solid. The remaining H2SO4 solution and the NaNO2 solution were added, maintaining the internal temperature at less than 5° C. The resulting mixture was stirred cold for 3 h, then warned to rt and stirred for 20 h. The reaction mixture was saturated with NaCl and extracted with 4×100 mL of EtOAc. The extracts were dried over MgSO4 and concentrated to afford 4.30 g (85%) of the title compound: 1H NMR (300 MHz) δ 0.13-0.18 (m, 2H), 0.48-0.54 (m, 2H), 0.89 (m, 1H), 1.67-1.76 (m, 2H), 4.37 (dd, J=6.4, 4.7 Hz, 1H).

1. additionwas treated with a sufficient amount of the acid solution
2. dissolutionto dissolve the solid
3. temperaturemaintaining the internal temperature at less than 5° C
4. customwarned to rt
5. stirringstirred for 20 h
6. extractionextracted with 4×100 mL of EtOAc
7. dry with materialThe extracts were dried over MgSO4
8. concentrationconcentrated