Stannous chloride dihydrate → 6-bromo-7-chloro-3,4-dihydroquinoxalin-2(1H)-one

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Reaction Steps

A solution of N-(5′-bromo-4′-chloro-2′-nitrophenyl)glycine sodium salt (0.255 g, 0.824 mmol, as prepared above) and tin (II) chloride dihydrate (0.560 g, 2.48 mmol, Aldrich, used as received) in ethanol (6 mL) was refluxed for 3 h. It was then cooled to room temperature and allowed to stand overnight at room temperature. The white solid was filtered and dried to yield 0.038 g (18%) of the pure (1H NMR) title compound as white flakes; m.p. 230-232° C.; 1H NMR (DMSO-d6): δ 3.732 (s, 2H), 6.371 (s, 1H), 6.830 (s, 1H), 6.912 (s, 1H), 10.437 (s, 1H). Extraction of the filtrate with ethyl acetate (30 mL) gave 0.136 g (68%) more product for a combined yield of 86%. The product was used as such for the next reaction.

Provenance & Evidence