Hydrochloric Acid → 2-Chloro-5-(methylsulfanyl)pyrazine

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Reaction Steps

Sodium nitrite (50.9 g, 0.74 mol) was dissolved in water (150 mL), followed by dropwise addition into a 5N aqueous hydrochloric acid solution (1.0 L) at 0° C. over 1 hour. Subsequently, 5-(methylsulfanyl)pyrazine-2-amine (40.4 g, 0.28 mol) synthesized in Example (97a) was added at 0° C. over 40 minutes, and stirring was carried out at 0° C. for 1 hour. The reaction solution was brought back to room temperature, and water (500 mL) was added, followed by extraction with ethyl acetate (1.0 L). The organic layer was washed with saturated brine, and subsequently dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified using silica gel column chromatography (elution solvent: ethyl acetate/hexane=10%-20%) to afford the desired compound (11.9 g, yield 26%) as a white solid.

Provenance & Evidence