Reaktion #540258

Reaktionsgleichung

acetic acid

sodium ethoxide

3,5-dichloro-2-hydrazinylpyridine

Diethyl maleate

→

product

Ausbeute 47.0%

ethyl 2-(3,5-dichloropyridin-2-yl)-5-oxopyrazolidine-3-carboxylate

Ausbeute 47.0%

Lösungsmittel

ethanol

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was heated
2. 2
   Temperaturto reflux for 5 minutes
3. 3
   Temperaturheated
4. 4
   Temperaturto reflux for 10 minutes
5. 5
   TemperaturThe mixture was cooled down to room temperature
6. 6
   Sonstigethe a precipitate formed
7. 7
   SonstigeThe solid was isolated via filtration
8. 8
   Waschenwashed with 40% aqueous solution of ethanol (3×50 mL)
9. 9
   Sonstigedried

Vorschrift

To a 500 mL flask, 300 mL anhydrous ethanol, sodium ethoxide (4.1 g, 61 mmol) and 3,5-dichloro-2-hydrazinylpyridine (10.00 g, 56 mmol) were added. The reaction mixture was heated to reflux for 5 minutes. Diethyl maleate (10.64 g, 61.0 mmol) was added dropwise and heated to reflux for 10 minutes. After being cooled to 65° C., the reaction mixture was neutralized with glacial acetic acid (13 g, 224 mmol) and diluted with 300 mL water. The mixture was cooled down to room temperature and the a precipitate formed. The solid was isolated via filtration, washed with 40% aqueous solution of ethanol (3×50 mL) and dried to give the product (8.00 g) as an orange solid in 47% yield. Melting point: 105-108° C.

Quelle