Urea → 5-tert-butylisoindole-1,3-dione

Participants

Reaction Conditions

Reaction Steps

Equimolar quantities of 4-t-butylphthalic anhydride (150.33 grams, 0.7361 mol) and urea (44.21 grams) were mixed with a thermometer in a 1 liter round bottom flask. The solids were heated slowly with a Meker burner. At 175° C., the reaction became exothermic and had to be cooled with an air gun. When the exotherm subsided, the temperature was increased to 250° C. and maintained at that temperature for 30 minutes. The flask was then cooled and 300 milliters of dimethylformamide was added, after which the solution was filtered by gravity to remove any solids which should not dissolve. Water (1 liter) was added, resulting in precipitation of 137.34 grams (0.6757 mole) of 4-t-butyl-phthalimide, which exhibited a melting point of 136.5° to 140° C. The identity of the 4-t-butyl-phthalimide product was confirmed by IR spectrum.

Provenance & Evidence