反応 #59249

反応方程式

MgSO4

NaOAc

3-Methyl-2-oxo-butyric acid ethyl ester

butyl-hydrazine oxalate salt

→

crude product ( 3b )

収率 85.4%

2-(Butyl-hydrazono)-3-methyl-butyric acid ethyl ester

収率 85.4%

溶媒

CHCl3

反応条件

後処理

1. 1
   温度The mixture was heated
2. 2
   温度to reflux for 3.5 hours under N2 atmosphere
3. 3
   温度After cooling
4. 4
   ろ過the solid was filtered off
5. 5
   濃縮the filtrate was concentrated under reduced vacuum
6. 6
   抽出The residue was first cleaned by an extraction between EtOAc (50 mL×3) and H2O (20 mL)
7. 7
   濃縮The organic layer was concentrated under reduced pressure
8. 8
   その他dried under high vacuum overnight

実験手順

To a solution of 3-Methyl-2-oxo-butyric acid ethyl ester (1c) (1.88 g, 13.04 mmol) in 45 mL of CHCl3, butyl-hydrazine oxalate salt (2.11 g, 11.85 mmol) was added followed by NaOAc (1.94 g, 23.4 mmol) and MgSO4 (1.43 g, 11.88 mmol). The mixture was heated to reflux for 3.5 hours under N2 atmosphere with stirring. After cooling, the solid was filtered off and the filtrate was concentrated under reduced vacuum. The residue was first cleaned by an extraction between EtOAc (50 mL×3) and H2O (20 mL). The organic layer was concentrated under reduced pressure and dried under high vacuum overnight to give 2.17 g of the crude product (3b) in 85.4% yield as a mixture of the E- and Z-isomers. This crude product was directly used in the next step without further purification. LC-MS (ESI+): m/e=215.4 [M+1]+, 237.1 [M+Na]+ (exact ms: 214.17).

出典