Acetone → 5-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid

Participants

Reaction Steps

232 g (1 mol) of 2-(hydroxymethyl)-5-(phenylmethoxy)-4H-pyran-4-one were put into a 10 1 stirring flask containing 6.61 of acetone and 400 ml of water. The clear solution was cooled to +5° C. by means of an ice-bath. While maintaining the temperature at +5° to 10° C., 640 ml of Jones Reagent (202 g CrO3, 600 ml water, 174 ml H2SO4) was added dropwise over a period of 1 hr. Stirring was continued for 2 hours without cooling. The reaction mixture was filtered through a glass frit and the dark-green residue washed with 500 ml of acetone. The filtrate was then evaporated until all of the acetone was removed. To the aqueous, partly crystalline product was added 1.2 1 of methanol, and this mixture was then heated to its boiling point. The resulting clear dark-green solution was placed in an ice-bath and the product allowed to crystallize. The crystalline product was filtered and washed with 500 ml of a cold solvent mixture consisting of 250 ml methanol +250 ml water and finally dried. Yield: 195 g=79%. From the mother liquor a further 5% of the product could be isolated.

Provenance & Evidence