Phosphorus oxychloride → 5-Bromo-4-chloro-1H-pyrrolo(2,3-b)pyridine

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Reaction Conditions

Reaction Steps

5-Bromo-1H-pyrrolo[2,3-b]pyridine 7-oxide (19.18 g, 90 mmol) were suspended in 200 mL NMP and cooled to −20° C. Phosphorus oxychloride (41 mL, 450 mmol) was added dropwise over 30 min. The mixture was allowed to warm to 23° C. over 1 h after which it was cooled on an ice bath and quenched with water (800 mL). The solids were filtered and recrystallized from ethyl acetate and hexanes to give 5-Bromo-4-chloro-1H-pyrrolo[2,3-b]pyridine (10 g, 48%). 1H NMR (500 MHz, DMSO-d6) δ 12.25 (bs, 1H), 8.4 (s, 1H), 7.65 (m, 1H), 6.52 (m, 1H). MS: m/z 230.8/232.8 (M+H+).

Provenance & Evidence