1,3-Dibromo-5,5-dimethylhydantoin → 2-Bromo-1,5,6,7-tetrahydro-4H-indol-4-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

1,3-Dibromo-5,5-dimethylhydantoin (Fluka, St. Louis, Mo.) (532 mg, 1.86 mmol) was added to a solution of 6,7-dihydro-1H-indol-4(5H)-one (Aldrich) (503.0 mg, 3.72 mmol) in DMF (13 mL) at 60° C. and the resulting mixture was stirred at 60° C. for 10 min. The mixture was then concentrated in vacuo (65° C., 24 Torr), and the residual oil was chromatographically purified (silica gel, 0-80% EtOAc/hexanes). The isolated product was taken up in EtOAc (100 mL) and sequentially washed with saturated aq. NaHCO3 (3×40 mL) and brine (40 mL). The organic layer was dried over Na2SO4, filtered, and concentrated in vacuo to provide 2-bromo-6,7-dihydro-1H-indol-4(5H)-one (664 mg, 3.10 mmol, 83% yield) as a white solid: 1H NMR (400 MHz, CDCl3) δ ppm 8.43 (1H, br. s.), 6.51 (1H, d, J=2.3 Hz), 2.79 (2H, t, J=6.2 Hz), 2.48 (2H, t, J=6.6 Hz), 2.15 (2H, quin, J=6.3 Hz). m/z (ESI, +ve) 214.1/216.1 (M+H)+.

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