4-Hydroxyphthalic acid → 5-Hydroxyisoindoline-1,3-dione

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-hydroxyphthalic acid (5.0 g, 27.0 mmol), acetic acid (25 mL), and ammonium carbonate (5.3 g, 55 mmol) was heated at 120° C. for 45 min followed by heating at 160° C. for 2 h. After cooling to room temperature, the reaction mixture was half-evaporated and then the reaction mixture was basified to pH 10 with 1 N NaOH followed by acidification to pH 5 at 0° C. with concentrated HCl. The resulting precipitate was filtered off, washed with water, dried at 60° C. under high vacuum over night, to afford the title compound (3.2 g, 71%) as an off-white crystalline solid.

Provenance & Evidence