2-Indanone → 1,4-dihydro-3H-2-benzopyran-3-one

Participants

Reaction Conditions

Reaction Steps

To 6.60 g (0.050 mol) of 2-indanone in 50 mL of dry dichloromethane was added 38.0 g (0.45 mol) of powdered anhydrous sodium bicarbonate, followed by 17.0 g (0.10 mol) of m-chloroperoxybenzoic acid. After stirring at 20° C. for 20 hours, further 3.0 g (0.017 mol) of the peracid was added and stirring continued for 24 hours. After addition of 200 mL of 10% aqueous Na2S2O3 stirring was continued until two clear phases had formed. The organic solution was separated and the aqueous phase was extracted with two 100 mL portions of dichloromethane. The combined organic solutions were dried (MgSO4) and concentrated under vacuum at 30° C. Solution in a mixture of ether and pentane, filtration and concentration under vacuum gave 6.7 g (90%) of 1,4-dihydro-3H-2-benzopyran-3-one, which could be recrystallized from ether or sublimed at 30°-40° C. (0.24 mm); mp 78°-79° C.; TLC Rf 0.36 (SiO2, CH2Cl2, brown-orange with iodine).

Provenance & Evidence