Bromine → 4-Bromo-2-methyl-2,3,6,7-tetrahydro-s-indacen-1(5H)-one

Participants

Reaction Conditions

Reaction Steps

31 g (162 mmol) of 2-methyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one (1a) were added to a suspension of 50 g (0.37 mol) of anhydrous aluminum trichloride in 200 ml of chloroform while stirring vigorously at 0° C. After stirring for one hour, a solution of 8 ml (160 mmol) of bromine in 20 ml of chloroform was added dropwise to the mixture at 0° C. and the mixture was subsequently stirred overnight. The reaction mixture was poured into 500 g of an ice/water mixture. The organic phase was separated off, washed with 5% strength sodium hydrogencarbonate solution and water and subsequently dried over magnesium sulfate. Filtration and removal of the solvent under reduced pressure gave 51 g of a red oil. GC-MS analysis indicated that the oil contained 84% of the desired compound (1b) and 14% of a dibromide by-product. The mixture was separated by column chromatography on silica gel using methylene chloride as eluant. This gave 18.7 g (44% yield) of the compound (1b).

Provenance & Evidence