反应详情

温度

5 °C

To a solution of 1,000 g (9.72 mol) sodium bromide in 2.1 liters 6N sulfuric acid under nitrogen was added 323.1 g (2.43 mol) L-aspartic acid and the resulting solution cooled to 5° C. To this was added in portions over 1.5 hours, 201.4 g (2.92 mol) sodium nitrite while keeping the temperature below 10° C. After the addition was completed, one liter of distilled water was added, followed by 73.07 g (1.22 mol) urea. The resulting mixture was poured into a separatory funnel and extracted with 2.5 liters ethyl ether. To the aqueous layer was added 500 g sodium chloride, and the mixture extracted three times with ether (3×1.25 liters). The combined ether layers were washed with brine, dried (Na2SO4) and the solvent evaporated in vacuo to yield 303 g (63%) of the desired compound; [alpha]D =-73.5° (c=0.6 in ethyl acetate); m.p. 185° C.

1. additionTo this was added in portions over 1.5 hours
2. customthe temperature below 10° C
3. additionAfter the addition
4. additionThe resulting mixture was poured into a separatory funnel
5. extractionextracted with 2.5 liters ethyl ether
6. additionTo the aqueous layer was added 500 g sodium chloride
7. extractionthe mixture extracted three times with ether (3×1.25 liters)
8. washThe combined ether layers were washed with brine
9. dry with materialdried (Na2SO4)
10. customthe solvent evaporated in vacuo