Ammonium Chloride → 5-Chloropyrazine-2-carbaldehyde

Participants

Reaction Steps

In tetrahydrofuran (66 mL) was dissolved methyl 5-chloropyrazine-2-carboxylate (3.3 g), and 1M diisobutylaluminum hydride/hexane solution (38.3 mL) was added dropwise to the solution under nitrogen atmosphere at −70° C. or lower over 10 minutes, and the resulting mixture was further stirred for 10 minutes. At −60° C. or lower, 1M diisobutylaluminum hydride/hexane solution (31.3 mL) was added dropwise to the mixture over 20 minutes, and the mixture was further stirred at −70° C. or lower for 1 hour. The reaction mixture was poured into a saturated aqueous ammonium chloride solution, and after stirring at room temperature, filtered with Celite. The filtrate was extracted with ethyl acetate, washed with a saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=100:0 to 80:20) to obtain 5-chloropyrazine-2-carbaldehyde (970 mg).

Provenance & Evidence