Reaktion #339130

Reaktionsgleichung

ethyl 2-methoxyimino-4-oxopentanoate

3-chloro-2-hydrazinopyridine

tetrahydrofuran

→

ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylate

Ausbeute 15.8%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated
2. 2
   Temperaturto reflux for 8 hours
3. 3
   EinengenThe reaction mixture was concentrated under reduced pressure
4. 4
   workup.ADDITIONWater was poured into the residue
5. 5
   Extraktionthe mixture was extracted with methyl t-butyl ether two times
6. 6
   WaschenThe combined organic layer was washed successively with a 1N aqueous sodium hydroxide solution, water
7. 7
   Trocknenan aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate
8. 8
   Einengenconcentrated under reduced pressure

Vorschrift

A mixture of 1.34 g of ethyl 2-methoxyimino-4-oxopentanoate, 1.23 g of 3-chloro-2-hydrazinopyridine, 25 ml of tetrahydrofuran and 50 ml of acetic acid was heated to reflux for 8 hours. The reaction mixture was concentrated under reduced pressure. Water was poured into the residue, and the mixture was extracted with methyl t-butyl ether two times. The combined organic layer was washed successively with a 1N aqueous sodium hydroxide solution, water and an aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography to obtain 0.30 g of ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylate of the formula:

Quelle