Phenothiazine → 2-(Trifluoromethylsulfonamido)ethyl methacrylate

Participants

Reaction Conditions

Reaction Steps

In a 1-liter three-neck flask equipped with a thermometer, a reflex condenser and a calcium chloride tube were placed 350 g of acetonitrile, 70.7 g (0.699 mol) of triethylamine, 33.1 g (0.200 mol) of 2-aminoethyl 2-methylacrylate hydrochloride and 0.2 g of phenothiazine as a polymerization inhibitor, followed by cooling to −30° C. with stirring. After the inside temperature of the flask reached −30° C. C, 36.5 g (0.240 mol) of trifluoromethanesulfonyl fluoride was introduced as a gas into the slurry over 1 hour. Upon completion of the gas introduction, the reaction solution was stirred for 1 hour and then warmed to room temperature. The solvent (acetonitrile) and the unreacted reaction substrate (trifluoromethanesulfonyl fluoride) were evaporated from the reaction solution under a reduced pressure. To the solution was added 1 liter of diisopropyl ether. The resulting slurry was subjected to filtration to filter out precipitates of triethylamine hydrochloride and triethylamine hydrofluoride. The filtrate was washed with 200 ml of 18% aqueous calcium chloride solution and subjected to two-phase separation. The organic phase was further washed three times with 200 g of 10% aqueous sodium chloride solution, and then, dried with 40 g of magnesium sulfate. The magnesium sulfate was removed by filtration. After that, 0.2 g of phenothiazine was added to the organic phase. The solvent was evaporated to obtain 44.2 g of a crude reaction product. The crude reaction product was subjected to distillation under a reduced pressure, thereby yielding 36.0 g of target 2-{[(trifluoromethyl)sulfonyl]amino}ethyl 2-methylacrylate as an organic fraction at 105-115° C./13Pa. The purity of the 2-{[(trifluoromethyl)sulfonyl]amino}ethyl 2-methylacrylate in the organic fraction was determined by gas chromatography to be 97.0%. The organic fraction was dissolved into a mixed solvent of diisopropyl ether and n-hexane under heating. The solution was cooled, thereby collecting 32.4 g of the 2-{[(trifluoromethyl)sulfonyl]amino}ethyl 2-methylacrylate as a white crystal. The purity of the 2-{[(trifluoromethyl)sulfonyl]amino}ethyl 2-methylacrylate in the crystal was determined by gas chromatography to be 99.0%. The yield of the 2-{[(trifluoromethyl)sulfonyl]amino}ethyl 2-me thylacrylate was 61%.

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