反应详情

To a solution of Compound 4 (2.94 g, 11.1 mmol) in anhydrous CH2Cl2 (40 mL) at 0° C. was added PPh3 (3.49 g, 13.3 mmol). NBS (2.37 g, 13.3 mmol) was added portionwise into the reaction mixture over 1 h. The resulting mixture was stirred at 0° C. for 30 minute after which the ice bath was removed, and the reaction mixture was stirred for 3 h. The resulting mixture was evaporated into an orange solid. The residue was dissolved in ether (100 mL). The solution was filtered, and the filtrate was evaporated and washed with ether again (3 times). The resulting clear filtrate was evaporated to give a white solid. The residue was then dissolved in ether (100 mL) and was passed through a short silica gel column to eliminate as much of the leftover PPh3 as possible. The resulting pure fractions (according to TLC analysis) were collected and dried overnight. The residue was on column chromatography eluted with 5% EtOAc in hexanes to provide Compound 5 (1.83 g, 50.4%) was collected at the ratio ethyl acetate to hexane as 1:11. 1H NMR (CDCl3) δ 1.47 (s, 9H), 3.10 to 3.18 (m, 2H), 3.31 (s, 2H), 3.30 to 3.40 (m, 2H), 3.88 (s, 2H), 7.20 to 7.38 (m, 5H); 13C NMR (CDCl3) δ 28.12, 30.47, 55.14, 55.85, 57.99, 80.96, 127.17, 128.26, 128.69, 138.74, 170.48. HRMS (Positive ion FAB) Calcd for C15H23N4O2Br [M+H]+ m/z 328.0929. Found: [M+Na]+ m/z 328.0912.

1. customwas removed
2. customThe resulting mixture was evaporated into an orange solid
3. dissolutionThe residue was dissolved in ether (100 mL)
4. filtrationThe solution was filtered
5. customthe filtrate was evaporated
6. washwashed with ether again (3 times)
7. customThe resulting clear filtrate was evaporated
8. customto give a white solid
9. customThe resulting pure fractions (according to TLC analysis) were collected
10. customdried overnight
11. washeluted with 5% EtOAc in hexanes