Phthalide → 1(3H)-Isobenzofuranone, 3-bromo-

Participants

Reaction Steps

Phthalide (10.0 g; 0.075 moles) and N-bromosuccinimide were refluxed in dry carbon tetrachloride (200 ml.) in the presence of a catalytic amount of α-azo-iso-butyronitrile for 3-4 hours. The end of the reaction was indicated by the disappearance of N-bromosuccinimide from the bottom of the reaction vessel and the accumulation of succinimide at the top. The succinimide was removed by filtration and the filtrate concentrated in vacuo to 15-20 ml. Cooling of this concentrate followed by filtration gave 13.0 g. (81% yield) of crude 3-bromophthalide, m.p. 75°-80°, as a white crystalline solid. The product was recrystallised from cyclohexane as colourless plates, m.p. 78°-80° with a 95% recovery.

Provenance & Evidence