4-Toluenesulfonyl chloride → 2-Bromo-7-iodo-5-tosyl-5H-pyrrolo[2,3-B]pyrazine

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 2-bromo-7-iodo-5H-pyrrolo[3,2-b]pyrazine [Intermediate AT] (1.1 g, 3.5 mmol) in anhydrous THF (20 mL) cooled to 0° C. was added NaH [60% dispersion in mineral oil] (0.17 g, 4.3 mmol). The reaction mixture was stirred for 20 min at 0° C., after which p-toluenesulfonyl chloride (0.73 g, 3.8 mmol) in THF (8 mL) was added. The resulting mixture was stirred at rt for 3 hr, after which it was diluted with EtOAc and washed with H2O and brine. The organic layer was separated, dried over Na2SO4, filtered, and evaporated in vacuo to yield a residue that was triturated with hexanes to yield the title compound (1.6 g, 94%) as a light yellow powder. 1H NMR (DMSO-d6, 300 MHz) δ 8.62 (d, J=7.5 Hz, 2H), 8.03 (s, 1H), 8.00 (s, 1H), 7.47 (d, J=8.1 Hz, 2H), 2.37 (s, 3H). HPLC retention time: 2.84 minutes. MS ESI (m/z): 478.0/480.0 (M+H)+, calc. 477.

Provenance & Evidence