Acetic Acid → Acetic Anhydride

Participants

Reaction Steps

To a mixed solution of acetic acid (10 mL) and acetic anhydride (5 mL), N-[4-(2-aminophenyl)-1H-imidazol-2-yl]-2-(mesityloxy)acetamide (Compound 19) (350 mg, 1.0 mmol) obtained in Example 19 was added, and the mixture was stirred for 16 hours at room temperature. The solvent was distilled off under reduced pressure, the resulting residue was dissolved in chloroform (50 mL), and the mixture was washed with 10% aqueous sodium carbonate solution. The organic layer was dried over anhydrous magnesium sulfate, and then distilled under reduced pressure. The resulting residue was dissolved in 10% ammonia/methanol solution (10 mL), and the mixture was stirred for 6 hours at room temperature. To the reaction solution, chloroform (50 mL) was added, and the mixture was washed with saturated aqueous sodium bicarbonate solution. The organic layer was dried over anhydrous magnesium sulfate, and then distilled under reduced pressure. The resulting crystals were dispersed in diethyl ether, collected by filtration and dried to give 250 mg of the title compound (yield 91%) expressed by the following formula (Ex. 20).

Provenance & Evidence