3-Hydroxyphthalic Anhydride

3-Hydroxyphthalic Acid Anhydride; 4-Hydroxy-1,3-isobenzofurandione; 4-Hydroxy-1,3-dihydro-2-benzofuran-1,3-dione; 4-Hydroxy-2-benzofuran-1,3-dione; 4-Hydroxyisobenzofuran-1,3-dione; NSC 80858;