Iodine → 5-chloro-3-iodo-1-tosyl-1H-pyrrolo[2,3-b]pyridine-4-carbaldehyde

Participants

Reaction Steps

To a solution of 5-chloro-1H-pyrrolo[2,3-b]pyridine-4-carbaldehyde (5.0 g, 27.7 mmol) in EtOH (100 mL) was added iodine (8.43 g, 33.2 mmol), sodium iodide (4.98 g, 33.2 mmol), and aqueous NaOH (1N, 35 mL, 35 mmol). After stirring for 4 h at room temperature, the reaction mixture was diluted with water (200 mL). An orange precipitate was collected by filtration and dried under vacuum. The solid was dissolved in DMF (60 mL) and sodium hydride (60%, 1.33 g, 33.2 mmol) was slowly added. The deep red solution was stirred for 30 min at room temperature. Tosyl chloride (5.81 g, 30.5 mmol) was added and the mixture was stirred at room temperature for 2 h. The mixture was diluted with EtOAc and the reaction was quenched with water. The organics were separated, washed with aqueous NaHSO3 (0.1 N) and brine, dried over MgSO4, and concentrated. Purification by silica gel chromatography (3:1:1 hexane/DCM/EtOAc) gave the title compound as a yellow solid (8.96 g, 70%). 1H NMR (500 MHz, DMSO-d6) δ 3.15 (s, 3 H), 8.24 (d, J=8.5 Hz, 2 H), 8.81 (d, J=8.5 Hz, 2 H), 9.17 (s, 1 H), 9.38 (s, 1 H), 11.81 (s, 1 H). [M+H] calc'd for C15H10ClIN2O3S, 461, 463; found, 461, 463.

Provenance & Evidence