Methanol → 1-Benzenesulfonyl-5-bromo-3-iodo-1H-pyrrolo[2,3-b]pyridine

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Reaction Steps

To a cooled solution of 45 (15.00 g, 46.6 mmol) in CH2Cl2 (210 mL) was added benzenesulfonyl chloride (9.18 mL, 71.8 mmol), 50% aq NaOH (13.04 mL) and Bu4NHSO4 (2.35 g, 6.94 mmol). The mixture was allowed to warm to ambient temperature and stirred for 2 h 45 min. The mixture was diluted with CH2Cl2 (200 mL) and washed with saturated brine solution (200 mL). The aqueous layer was extracted with CH2Cl2 (2×200 mL), the combined organics were dried (MgSO4) and concentrated to afford a pale yellow solid. The solid was stirred vigorously with cold methanol for 1 h and the resulting precipitate was filtered off and dried under vacuum to afford 46 as a white solid (20.90 g, 97%); 1H NMR (400 MHz, CDCl3) δ7.49 (t, J=15.5, 7.4 Hz, 2H), 7.60-7.64 (m, 1H), 7.81 (d, J=2.2 Hz, 1H), 7.87 (s, 1H), 8.17-8.19 (m, 2H), 8.45 (d, J=2.1 Hz, 1H).

Provenance & Evidence