Acetic Acid → Ethyl 2-(3,5-dichloropyridin-2-yl)-5-oxopyrazolidine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence