Kojic Acid → Chlorokojic acid

Participants

Reaction Steps

A 2-litre 3-neck round bottom flask was equipped with a mechanical stirrer. The flask was charged with kojic acid (0.25 kg, 1.759 mol) and 750 ml acetonitrile at 0° C. The kojic acid was insoluble in acetonitrile and stayed as a suspension. Thionyl chloride (140 ml, 1.919 mol) was added dropwise via a dropping funnel at ice bath temperature. The solid slowly dissolved to give a red clear solution. After 15 minutes, a white solid appeared. After 3 hrs at 0° C., the insoluble solid was filtered. The solid was filtered by suction filtration. The solid was mixed with water (0.5 L) and then filtered. The acetonitrile mother liquor was reduced to 15% of the original volume and filtered. The solid was washed with water (200 ml) and then acetonitrile (50 ml). The combined solid was dried to constant weight (269 g, 95.2% yield). M.p. 166-168° C. [lit value 166-167° C.]. 1H-NMR (DMSO-d6) δ: 4.66 (s, 2H, CH2Cl), 657 (s, 1H, CH), 8.12 (s, 1H, CH), 9.3 (br. s, 1H, OH).

Provenance & Evidence