4-Hydroxyphthalic anhydride

610-35-5

27550-59-0

The sublimation reaction was carried out at 220 °C and under vacuum conditions (~10 mbar) using 4-hydroxyphthalic acid (1 g, 5.49 mmol) as the raw material. Upon completion of the reaction, the resulting white solid 5-hydroxyisobenzofuran-1,3-dione (675 mg, 4.11 mmol, 74.9% yield, MS/ESI+ 164.9 [MH]+) was collected. The product is to be stored under vacuum and used directly in subsequent reaction steps.