反应详情

To a stirred solution of indole 1 (Example 11, Step 3; 200 mg, 0.42 mmol) in DMF (5 mL) under inert atmosphere were added Cs2CO3 (206 mg, 0.63 mmol) and tert-butyl 4-bromobutanoate (141 mg, 0.63 mmol) at RT and stirred for 16 h. The mixture was diluted with ice cold water (20 mL) and extracted with EtOAc (3×30 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated under reduced pressure to obtain the crude. This was purified (silica gel chromatography; 20% EtOAc/hexanes) to afford compound 2 (180 mg, 70%) as a pale brown oil. 1H NMR (400 MHz, CDCl3): δ 7.67 (s, 1H), 7.64 (s, 1H), 7.63-7.60 (m, 1H), 7.18 (d, J=8.4 Hz, 1H), 7.10-7.06 (m, 1H), 6.93 (t, J=8.0 Hz, 1H), 6.77 (t, J=7.6 Hz, 1H), 4.41 (q, 2H), 4.28 (t, J=6.8 Hz, 2H), 2.28-2.19 (m, 4H), 1.74-1.66 (m, 1H), 1.46 (s, 9H), 1.41 (t, J=7.2 Hz, 3H), 1.06-1.02 (m, 2H), 0.89-0.84 (m, 2H); LC-MS (ESI): m/z 618.6 (M+H+).

1. extractionextracted with EtOAc (3×30 mL)
2. dry with materialThe combined organic extracts were dried (Na2SO4)
3. filtrationfiltered
4. concentrationconcentrated under reduced pressure
5. customto obtain the crude
6. customThis was purified (silica gel chromatography; 20% EtOAc/hexanes)