Acetic Anhydride → Ethyl 2-formamidothiazol-4-acetate

反応式

[C:1](OC(=O)C)(=[O:3])C.[NH2:8][C:9]1[S:10][CH:11]=[C:12]([CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])[N:13]=1>C(O)=O>[CH:1]([NH:8][C:9]1[S:10][CH:11]=[C:12]([CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])[N:13]=1)=[O:3]

参加物

実験手順

To acetic anhydride (384 ml.) was added dropwise 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-aminothiazol-4-yl)acetate, which can be represented as ethyl 2-(2-imino-2,3-dihydrothiazol-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-formylaminothiazol-4-yl)acetate, which can be represented as ethyl 2-(2-formylimino-2,3-dihydrothiazol-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.).