Kojic Acid → Chlorokojic acid

Participants

Reaction Steps

Kojic Acid (50.0 g; 352 mmol)—an inhibitor of tyrosinase with an EC50 of 17.0 μM—was carefully added in portions over 30 min to a stirring solution of thionyl chloride (150 mL) containing hexanes (100 mL). After an additional 3.5 hours of stirring, the product was collected by Büchner filtration and washed with hexanes (2×50 mL). The light yellow solid was dried over night under vacuum to afford chloro-kojic acid (50.9 g; 90% yield). Chloro-kojic acid was found to be a more potent inhibitor of tyrosinase than kojic acid with an EC50 of 6.8 μM. 1H NMR (DMSO-d6) δ 9.30 (br s, 1H; 5-OH); 8.12 (s, 1H; 6-H); 6.56 (s, 1H; 3-H); 4.66 (s, 2H; 2-CH2Cl).

Provenance & Evidence