Butyl vinyl ether → N-Methyl-N-phenylprop-2-enamide

To a solution of N-methylformanilide (30 g), butyl vinyl ether (22.2 g) in 25 ml of 1,4-dioxane under stirring at 10–15° C., a solution of bis-trichloromethylcarbonate (28.3 g) in 50 ml of 1,4-dioxane is added dropwise in 90 min. The reaction mixture is kept under stirring at room temperature overnight, then the solvent is evaporated under reduced pressure. Tert-butyl methyl ether (75 ml) and water (55 ml) are added, the mixture is cooled at about 5–10° C. and the pH is corrected to about 7 by adding sodium hydroxide 30% aqueous solution (55 g). After separation of the phases, the aqueous layer is extracted with tert-butyl methyl ether (70 ml) and the combined organic layers are evaporated under reduced pressure. To the residue tert-butyl methyl ether (50 ml) is added and the mixture is cooled at −15° C. for 90 minutes. The precipitate is filtered on Buchner, washed twice with tert-butyl methyl ether (25 ml×2) and dried at room temperature under vacuum overnight. 25.21 g of pure compound are obtained (70% molar yield)