Acetonitrile → 2-Bromo-7-(2-methoxy-phenyl)-5-(toluene-4-sulfonyl)-5H-pyrrolo[2,3-b]pyrazine

Participants

Reaction Conditions

Reaction Steps

A 50-ml round bottom flask was charged with 2-Bromo-7-iodo-5-(toluene-4-sulfonyl)-5H-pyrrolo[2,3-b]pyrazine (423 mg, 0.885 mmol), 2-methoxyphenylboronic acid (148 mg (0.973 mmol) and dichlorobis(triphenylphosphino)palladium(II) (31 mg, 0.04 mmol). To this mixture was added acetonitrile (10 mL) and a 2 M aqueous solution of sodium bicarbonate (5 mL). The reaction mixture was stirred at 40° C. for 1 hour, then 55° C. for another hour. The crude reaction mixture was distributed between ethyl acetate and a saturated aqueous solution of sodium bicarbonate. The aqueous phase was then extracted with ethyl acetate and the combined organic phases were dried over sodium sulfate, filtered and concentrated. The crude product was then purified by flash silica gel chromatography using a gradient of ethyl acetate in hexanes to afford 2-Bromo-7-(2-methoxy-phenyl)-5-(toluene-4-sulfonyl)-5H-pyrrolo[2,3-b]pyrazine (139 mg, 34% yield) as a light yellow solid; the bis-addition product 2,7-Bis-(2-methoxy-phenyl)-5-(toluene-4-sulfonyl)-5H-pyrrolo[2,3-b]pyrazine (213 mg, 50% yield) was also obtained. MS: m/z 457.9/460.0 [MH+]; MS: m/z 486.1 [MH+] (bis-addition product).

Provenance & Evidence