Potassium Carbonate → 7-(3-Bromo-phenyl)-2-chloro-5H-pyrrolo[2,3-b]pyrazine

Participants

Reaction Steps

A 50 ml round bottom flask was charged under nitrogen with 2-chloro-7-iodo-5-(toluene-4-sulfonyl)-5H-pyrrolo[2,3-b]pyrazine (6) (950 mg, 2.2 mmol), 3-bromophenyl boronic acid (440 mg, 2.2 mmol), tetrakis-triphenylphosphine palladium (50 mg, 0.04 mmol), 2M aqueous potassium carbonate (2.2 ml, 4.4 mmol) in a toluene/ethanol mixture (15/3 ml) under nitrogen. The reaction mixture was refluxed for 18 h, then allowed to cool to room temperature. The solution was diluted with ethyl acetate (˜70 ml). The organic was washed with brine, dried over magnesium sulfate and concentrated in vacuo, The residue was triturated in dichloromethane/methanol. A pale yellow solid was removed by filtration (300 mg). The residue was taken up in a tetrahydrofuran/methanol/1M NaOH mixture (4/1/1 ml) and stirred at room temperature for 2 h. The reaction mixture was diluted with ethyl acetate, washed with brine, dried over magnesium sulfate and concentrated in vacuo. The residue was triturated in methanol. A solid was filtered off as the title compound (10 mg, 1%). 1H NMR (DMSO-d6): 7.35-7.45 (2H, m), 8.10-8.15 (1H, d), 8.35 (1H, s), 8.4 (1H, s), 8.6 (1H, s). MS (ES+): 310, 312.

Provenance & Evidence