Reaktion #56559

Reaktionsgleichung

acetic anhydride

ethyl 2-(2-aminothiazol-4-yl)acetate

ethyl 2-(2-imino-2,3-dihydrothiazol-4-yl)acetate

→

ethyl 2-(2-formylaminothiazol-4-yl)acetate

Lösungsmittel

formic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturunder cooling below 35° C.
2. 2
   Temperaturcooling
3. 3
   workup.STIRRINGstirring
4. 4
   workup.STIRRINGthe mixture was stirred for 1 hour at room temperature
5. 5
   SonstigeAfter the reaction
6. 6
   workup.DISTILLATIONthe solvents were distilled off
7. 7
   workup.ADDITIONTo the residue was added diisopropyl ether (2500 ml.)
8. 8
   workup.STIRRINGthe mixture was stirred for 1 hour at room temperature
9. 9
   FiltrationThe precipitates were collected by filtration
10. 10
    Waschenwashed with diisopropyl ether
11. 11
    Sonstigedried

Vorschrift

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.).

Quelle