Hydrochloric Acid → Ethyl[(Z)-2-cyano-1-(2,4-difluorophenyl)ethenyl]carbamate

Participants

Reaction Steps

At 40° C., 769 mg (33.44 mmol) of sodium were dissolved in ethanol (41 ml). 4.14 g (22.29 mmol) of 3-amino-3-(2,4-difluorophenyl)prop-2-enonitrile and 5.79 g (49 mmol) of diethyl carbonate were added, and the reaction solution was stirred under reflux for 4 h. 200 ml of ethyl acetate and 150 ml of water were added to the reaction mixture and the pH was adjusted with hydrochloric acid to pH=5. The organic phase was separated off, dried over magnesium sulfate and concentrated on a rotary evaporator. The residue was triturated with diisopropyl ether and the white precipitate was filtered off with suction. More product was obtained by separating the mother liquor by preparative HPLC (Method 11). Drying under high vacuum gave a total of 4.92 g (49% of theory) of the product as a mixture of E and Z isomers which was used without further purification.

Provenance & Evidence