Hydrogen Bromide → 1(3H)-Isobenzofuranone, 6-bromo-3-methyl-

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Reaction Steps

58.25 g of 6-amino-3-methylphtalide (3-4) was dissolved in 1.5 l of 4.7% hydrobromic acid and 405.60 g of copper (II) bromide was added thereto, and under cooling with ice, 400 ml of aqueous solution of 41.92 g of sodium nitrite was dropped thereto. The resulting mixture was stirred at the same temperature for 2 hours and then stirred at a room temperature for 15 hours, and thereafter, extracted with chloroform. The resulting organic layer was washed with saturated sodium bicarbonate solution and saturated salt water in order, and dried over anhydrous magnesium sulfate, and thereafter, the solvent was distilled off under reduced pressure, the resulting residue was purified by silica gel column chromatography (eluent; hexane:ethyl acetate=3:1) to obtain 71.56 g of 6-bromo-3-methylphtalide (3-5).

Provenance & Evidence