反应详情

温度

80 °C

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).

1. temperaturecooling
2. customevaporated
3. customto remove ethanol
4. temperaturethe mixture was refluxed for 1 hour
5. customwas adjusted to pH 3.5 with concentrated hydrochloric acid at 10°-20° C.
6. filtrationthe resulting precipitate was collected by filtration