Phosphorus oxychloride → 4-Chloro-1H-pyrrolo[2,3-b]pyridine

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Reaction Steps

1H-Pyrrolo[2,3-b]pyridine-N-oxide (Reference Example 65) (10.0 g) in phosphorous oxychloride (75 mL) was heated at reflux for 8 hours. The excess phosphorous oxychloride was evaporated and the residue was taken up in water and the solution was brought to a pH=8–9, the resultant precipitate was filtered and air-dried to give the title compound as an off-white solid (10.2 g). MS: 152 (MH+). 1H NMR (CDCl3): δ 8.2 (d, 1H), 7.5 (d, 1H), 7.2 (d, 2H), 6.6 (d, 2H).

Provenance & Evidence