反応 #1673837

反応方程式

ethyl ethoxymethylenecyanoacetate

hydrazinoacetaldehyde diethyl acetal

→

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

収率 27.6%

溶媒

ethanol

water

反応条件

後処理

1. 1
   温度cooling
2. 2
   その他evaporated
3. 3
   その他to remove ethanol
4. 4
   温度the mixture was refluxed for 1 hour
5. 5
   その他was adjusted to pH 3.5 with concentrated hydrochloric acid at 10°-20° C.
6. 6
   ろ過the resulting precipitate was collected by filtration

実験手順

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

出典