Quinine

  Quinine is one of the alkaloids which is included in the bark of cinchona tree and has been researched since 19^th century.¹⁾ It has an anti-malarial activity^2-4) and is considered to inhibit heme polymerase of plasmodium and to indicate toxicity to plasmodium. There are other antimalarial substances such as chloroquine diphosphate [C2301], hydroxychloroquine sulfate [H1306] and artemisinin [A2118]. (The product is for research purpose only)

Typical Procedure:
p-Benzoquinone (42.6 mg, 0.4 mmol) and quinine (1.3 mg, 2 mol%) are dissolved in 1,2-dichloroethane (2 mL). The solution is stirred at 25 °C for 10 min, after which a 4-substituted pyrazol-5-one (0.2 mmol) is added to the mixture. The solution is stirred at 25 °C for 24 h. Next, the solvent is removed under reduced pressure. The residue is directly subjected to column chromatography (petroleum ether/EtOAc = 10:1–6:1) to afford the desired product.