Реакция #59249

Уравнение реакции

MgSO4

NaOAc

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

butyl-hydrazine oxalate salt

→

crude product ( 3b )

Выход 85.4%

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

Выход 85.4%

Растворители

CHCl3

Условия реакции

Обработка

1. 1
   ТемператураThe mixture was heated
2. 2
   Температураto reflux for 3.5 hours under N2 atmosphere
3. 3
   ТемператураAfter cooling
4. 4
   Фильтрацияthe solid was filtered off
5. 5
   Концентрированиеthe filtrate was concentrated under reduced vacuum
6. 6
   ЭкстракцияThe residue was first cleaned by an extraction between EtOAc (50 mL×3) and H2O (20 mL)
7. 7
   КонцентрированиеThe organic layer was concentrated under reduced pressure
8. 8
   Другоеdried under high vacuum overnight

Методика

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).

Источник