1,3-Dibromo-5,5-dimethylhydantoin → 2-(1-Bromoethyl)-3,5-dichloroquinoxaline

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Reaction Steps

3,5-Dichloro-2-ethylquinoxaline (1.10 Kg, 4.84 mol) was dissolved in CCl4 (4.4 L) at rt. 1,3-dibromo-5,5-dimethylhydantoin (762 g, 2.66 mol) and benzoyl peroxide (116 g, 0.48 mol) were then added. The resulting suspension was heated at reflux for 2 h. At this time LC-MS analysis showed that the reaction was complete. After cooling to rt white crystals formed in the reaction vessel. The white crystals were collected by filtration, washed with saturated aqueous NaHCO3 (3×5 L), and dried under high vacuum to give 2-(1-bromoethyl)-3,5-dichloroquinoxaline as a white solid (1.05 Kg). 1H NMR (DMSO-d6) δ ppm 8.04-8.12 (m, 2H), 7.78-7.90 (m, 1H), 5.76-5.84 (m, 1H), 2.09 (d, J=6.7 Hz, 3H). Mass Spectrum (ESI) m/z=304.8 [(M+1) (79Br)], 306.9 [(M+1) (81Br)].

Provenance & Evidence