Acetic Anhydride → Ethyl 2-formamidothiazol-4-acetate

Beteiligte Stoffe

Reaktionsschritte

To acetic anhydride (384 ml.) was dropwise added formic acid (169.2 ml.) over 15 to 20 minutes under cooling below 35° C., and the mixture was stirred for 1 hour at 55° to 60° C. To the mixture was added ethyl 2-(2-amino-1,3-thiazol-4-yl)acetate, which can be represented as ethyl 2-(2-imino-2,3-dihydro-1,3-thiazol-4-yl)acetate, (506 g.) over 15 to 20 minutes under ice-cooling and stirring, and then the mixture was stirred for 1 hour at room temperature. After the reaction, the solvents were distilled off. To the residue was added diisopropyl ether (2500 ml.), and the mixture was stirred for 1 hour at room temperature. The precipitates were collected by filtration, washed with diisopropyl ether and then dried to give ethyl 2-(2-formylamino-1,3-thiazol-4-yl)acetate, which can be represented as ethyl 2-(2-formylimino-2,3-dihydro-1,3-thiazol-4-yl)acetate, (451.6 g.), mp. 125° to 126° C. The remaining filtrate was concentrated, and the residue was washed with diisopropyl ether (500 ml.) and then dried to give further the same object compound (78.5 g.).

Herkunft & Nachweise