2,5-dimethyl-9-methoxy-2,3-dihydro-7H-furo[3,2-g][-1]benzopyran-7-one → 9-Methoxy-2,5-dimethyl-7h-furo[3,2-g]chromen-7-one

Participants

Reaction Steps

A solution of 10.36 g (0.0422 mol) of 2,5-dimethyl-9-methoxy-2,3-dihydro-7H-furo[3,2-g][-1]benzopyran-7-one in 150 ml of diphenyl ether was treated with 6.0 g of 10% palladium on charcoal. The mixture was heated under reflux for 5.0 hrs, cooled, and filtered over celite. The catalyst was further washed with methanol, and the filtrate was then concentrated to remove the methanol. The residue was diluted with 1.5 l. of pet. ether and stirred overnight. The product was filtered, washed with pet. ether, dried, and passed through a silica column, eluting with ethyl acetate/benzene, 1:4, to yield pure 9-methoxy-2,5-dimethyl-7H-furo[3,2-g][1]benzopyran-7-one, m.p. 154°-155° (ethanol).

Provenance & Evidence