Sulfuric Acid → (4R)-7-hydroxy-4-(3-hydroxy-4-methoxyphenyl)chroman-2-one

Participants

Reaction Steps

0.5 g para-toluenesulfonic acid and 1.5 ml concentrated sulfuric acid were added to a mixture of 50 mmol isoferulic acid and 75 mmol resorcinol in 75 ml of 1,4-dioxane and heated under reflux for 14 hours. As the reaction was not completed at this time point according to LC-MS, a further 1.5 ml of concentrated sulfuric acid was added and the mixture was heated for a further 10 hours. Then a large part of the solvent was removed in a rotary evaporator and the product mixture was taken up in 200 ml ethyl acetate. The organic phase was washed twice with 50 ml demineralized water and 5% sodium bicarbonate solution each time and once with saturated sodium chloride solution. The organic phase was then dried over sodium sulfate and after removing the solvent, the product was purified by silica-gel column chromatography (solvent: ethyl acetate/hexane 4:5), recrystallized from a solvent mixture of diethyl ether/pentane (1:6) and the resultant product was dried at 60° C. in a vacuum drying cabinet.

Provenance & Evidence