Ethyl Acetate → 5-tosyl-5H-pyrrolo[2,3-b]pyrazine-2-carbaldehyde

Participants

Reaction Steps

To a solution of (E)-2-styryl-5-tosyl-5H-pyrrolo[2,3-b]pyrazine (1.2 g, 3.2 mmol) in 1,4-dioxane (20 mL) and water (2.0 mL) was added sodium periodate (2.73 g, 12.8 mmol) followed by osmium tetroxide (2.5 wt % in t-BuOH, 4.01 mL, 0.320 mmol). The reaction mixture was stirred for about 1 day at ambient temperature and then additional sodium periodate (2.73 g, 12.78 mmol) and osmium tetroxide (2.5 wt % in t-BuOH, 4.01 mL, 0.320 mmol) were added. After stirring for about 2 days, a solution of 10% aqueous Na2S2O3 (100 mL) and EtOAc (100 mL) was added. The organic layer was separated, dried over anhydrous Na2SO4, filtered, and coned under reduced pressure to give a solid, which was triturated with heptane to remove benzaldehyde. The resulting solid was dried in vacuo to provide 5-tosyl-5H-pyrrolo[2,3-b]pyrazine-2-carbaldehyde as a brown solid (0.77 g, 80%): LC/MS (Table 1, Method a) Rt=2.01 min; MS m/z: 334 (M+H)+.

Provenance & Evidence