N-bromobutanimide → 5-Bromo-1-(1,4-dioxaspiro[4.5]decan-8-yl)indoline

Participants

Reaction Steps

A solution of compound 3 (3.45 g, 13.30 mmol) in dry DMF (30 mL) was treated with N-bromosuccinimide (2.36 g, 13.30 mmol) in DMF (20 mL) at 0° C. over a period of 30 min. The reaction was stirred at same temperature for 3.5 h. The reaction was diluted with water (200 mL) and product was extracted into ethyl acetate (3×25 mL). The combined ethyl acetate layer was washed with water (2×50 mL), brine (25 mL) and dried (Na2SO4). The solvent was evaporated and the crude product was purified by column chromatography on silica gel (ethyl acetate:hexanes, 1:4) to obtain compound 4 (4.05 g, 90%) as a syrup. 1H NMR (CDCl3) δ 7.12-7.10 (m, 2H), 6.25 (d, J=9.0 Hz, 1H), 3.95 (s, 4H), 3.38 (t, J=16.8 Hz, 3H), 2.91 (t, J=16.8 Hz, 2H), 1.86-1.57 (m, 8H). MS-ESI (m/z, %): 340 (98), 338 (M+, 100), 198 (18).

Provenance & Evidence