Acetic Anhydride → 3-Acetamidophthalic Anhydride

Participants

Reaction Steps

A mixture of 3-aminophthalic acid (108 g, 596 mmol) and acetic anhydride (550 mL) was charged into a 1-L 3-necked round bottom flask equipped with a mechanical stirrer, a thermometer, and a condenser. The reaction mixture was refluxed for 3 hours, cooled to ambient temperature, and kept at 0-5° C. for another 1 hour. The crystalline solid was collected by vacuum filtration and washed with ether. The solid product was dried in vacuum at ambient temperature to a constant weight to yield 75 g (61% yield) of 3-acetamidopthalic anhydride as a white product. The product in CDCl3 was characterized by a 1H NMR spectrum showing the following chemical shifts (δ in ppm): 2.21 (s, 3H), 7.76 (d, 1H), 7.94 (t, 1H), 8.42 (d, 1H), 9.84 (s, 1H).

Provenance & Evidence