Hydrochloric Acid → 8-Bromo-5-carboxy-5,6-dihydro-1H-pyrrolo[1,2,3-de]quinoxaline-2,3-dione

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Reaction Steps

To a solution of 8-bromo-5-methoxycarbonyl-5,6-dihydro-1H-pyrrolo[1,2,3-de]quinoxaline-2,3-dione (256 mg, 0.76 mmol) in a mixture of THF (5 mL) and methanol (5 mL) was added aqueous 1N NaOH (2.5 mL) and the mixture was stirred for 12 h at room temperature. Aqueous 1N HCl was added and the resulting mixture was concentrated to ca. 5 mL. The precipitates formed were collected by filtration, washed with distilled water, and dried in vacuo to give 256 mg of the title compound (quant): mp 285° C. (dec); 1H NMR (270 MHz, DMSO-d6) δ13.45 (bs, 1H), 12.09 (s, 1H), 7.22 (d, 1H, J=1Hz), 7.08 (d, 1H, J=1 Hz), 5.18 (dd, 1H, J=11, 4 Hz), 3.79 (dd, 1H, J=17, 11 Hz), 3.33 (dd, 1H, J=17, 4 Hz).

Provenance & Evidence