Kojic Acid → Chlorokojic acid

Participants

Reaction Steps

A 2-liter 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 (0.5L) 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. 166-1680° C. [lit value 166-167° C.]. 1H-NMR (DMSO-d6) δ: 4.66 (s, 2H, CH2Cl), 6.57 (s, 1H, CH), 8.12 (s, 1H, CH), 9.3 (br. s, 1H, OH).

Provenance & Evidence