Urea → 5-Fluoroisoindoline-1,3-dione

Participants

Reaction Conditions

Reaction Steps

8.2 parts (0.137 mole) of urea are added to 185 parts of the distillate (containing 43.4 parts (0.261 mole) of 4-fluorophthalic anhydride). The mixture is stirred for 3 hours at 135°-140° C., after which the evolution of gas is complete, and is finally heated for a further 10 minutes at 160° C. The solvent is distilled off (144.2 parts) at 115°-130° C. and under 0.3 mbar. According to gas chromatography, it contains 9.6 parts of 4-fluorophthalimide. The distillation residue is stirred with water, and the product is filtered off under suction, washed and dried, 31 parts of 4-fluorophthalimide of melting point 174°-176° C. being obtained. The total yield is 40.6 parts (94.2% of theory) of 4-fluorophthalimide.

Provenance & Evidence