Kojic Acid → 5-Hydroxy-2-{[(oxan-2-yl)oxy]methyl}-4H-pyran-4-one

Participants

Reaction Steps

To a solution of 56.8 g of 5-hydroxy-2-hydroxymethyl-4-pyrone (kojic acid) in 2 L of methylene chloride, 0.4 g of p-toluenesulfonic acid monohydrate was added and the mixture was stirred for 1.5 h. The reaction mixture was extracted with 3% sodium hydroxide solution twice and then the combined aqueous phase was neutralized to pH 8 with 0.5 M sodium dihydrogen phosphate. An extractive work-up (methylene chloride) follwed by recrystallization afforded 67 g (75%) of the title compound (mp 94° C.), NMR (CDCl3) 60 MHz: 4.32 (d, J=14, 1H, right hand of AB pattern), 4.61 (d, J=14, left half of AB pattern), 4.73 (broad S, 1H, acetal H), 6.60 (S, 1H, H-3), 7.86 (S, 1H, H-5) ppm; IR (CHCl3) 3430, 1640, 1600 cm-1 /UV (MeOH): 270 nm (Σ7,400).

Provenance & Evidence