5493-24-3

2439-85-2

13831-31-7

5493-24-3

At room temperature, 100 mmol of N-bromophthalimide (compound of Formula I) and 100 mmol of acetoxyacetyl chloride (compound of Formula II) were mixed with 16 mmol of catalyst (a mixture of 8 mmol of tetracarbonyldiborodiruthenium and 8 mmol of copper triphenylphosphine (Cu(PPh3)Br)). Subsequently, 140 mmol of acetoxyacetyl chloride, 30 mmol of p-toluenesulfonic acid (as an acidic compound) and 6 mmol of additive L dissolved in a mixed organic solvent of acetonitrile and 1,4-dioxane in a volume ratio of 2:10 were added to the reaction system. The reaction mixture was heated to 80°C and the reaction was stirred at this temperature for 10 hours. Upon completion of the reaction, the reaction system was filtered and the pH of the filtrate was adjusted to neutral with base. Subsequently, a decompression distillation was carried out and the residue was purified by silica gel column chromatography using an equal volume of a solvent mixture of chloroform and ethyl acetate as eluent. Finally, methyl (1,3-dioxoisoindolin-2-yl)acetate (compound of formula III, where Ac represents acetoxy) with a melting point of 109-110°C was obtained by decompression distillation in 90.8% yield.