反应详情

To a solution of Citrulline (2.54 g, 14.50 mmole) and Sodium Bicarbonate (1.28 g) in water (40 mL) was added Boc-Val-OSu (4.34 g, 13.81 mmole) dissolved in dimethoxyethane (DME). To aid the solubility of the mixture tetrahydrofuran (10 mL) was added. The mixture thus obtained was let stir overnight at room temperature. Aqueous citric acid (15%, 75 mL) was added and the mixture was extracted with 10% 2-propanol/ethyl acetate (2×100 mL). The organic layer was washed with brine (2×150 mL) and the solvents were removed on the rotovap. The resulting white solid was dried in vacuo for 5 hours and then treated with ether (100 mL). After brief sonication and trituration, the white solid product was collected by filtration (1.39 g, 27%). 1H NMR (CD3OD) δ 0.91 (dd, 3H), 0.98 (dd, 3H), 1.44 (s, 9H), 1.70 (m, 2H), 1.87 (m, 2H), 2.02 (m, 2H), 3.11 (t, 2H), 3.89 (t, 1H), 4.39 (q, 1H), 8.22 (d, 1H) ppm; LC-MS (ESI) 375 (M+H+).

1. additionwas added
2. customThe mixture thus obtained
3. extractionthe mixture was extracted with 10% 2-propanol/ethyl acetate (2×100 mL)
4. washThe organic layer was washed with brine (2×150 mL)
5. customthe solvents were removed on the rotovap
6. customThe resulting white solid was dried in vacuo for 5 hours
7. additiontreated with ether (100 mL)
8. customAfter brief sonication and trituration
9. filtrationthe white solid product was collected by filtration (1.39 g, 27%)