Reaktion #1673837

Reaktionsgleichung

ethyl ethoxymethylenecyanoacetate

hydrazinoacetaldehyde diethyl acetal

→

1-(2,2-diethoxyethyl)-4-carboxy-5-aminopyrazole

Ausbeute 27.6%

Lösungsmittel

ethanol

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   Sonstigeevaporated
3. 3
   Sonstigeto remove ethanol
4. 4
   Temperaturthe mixture was refluxed for 1 hour
5. 5
   Sonstigewas adjusted to pH 3.5 with concentrated hydrochloric acid at 10°-20° C.
6. 6
   Filtrationthe resulting precipitate was collected by filtration

Vorschrift

To a suspension of ethyl ethoxymethylenecyanoacetate (21.7 g) in ethanol (65 ml) was added dropwise a solution of hydrazinoacetaldehyde diethyl acetal (19 g) in water (19 ml) under ice-cooling. The mixture was stirred at 80° C. for 1.5 hours and evaporated to remove ethanol. To the residue was 4N sodium hydroxide (64 ml), and the mixture was refluxed for 1 hour. The mixture was adjusted to pH 3.5 with concentrated hydrochloric acid at 10°-20° C., and the resulting precipitate was collected by filtration to give 1-(2,2-diethoxyethyl)-4-carboxy-5-aminopyrazole (8.60 g). IR (Nujol) : 3460, 3360, 1645, 1620, 1545 cm-1

Quelle