Methanesulfonic Acid → 4-Methyltetrahydropyran-4-yl (2-methacryloyloxyethyl)carbamate

Participants

Reaction Conditions

Reaction Steps

In a three-necked flask having an inner volume of 50 mL equipped with a thermometer and a stirring apparatus were charged 1.00 g (8.51 mmol) of 4-methyltetrahydropyran-4-ol, 1.0 mg of 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl, 4.0 g of isopropyl ether, and 1.42 g (8.94 mmol) of 2-methacryloyloxyethyl isocyanate. After the mixture was cooled by ice water to an inner temperature of 5° C., 250 mg (2.55 mmol) of methanesulfonic acid was added dropwise. After stirring the reaction mixture for 10 hours with the reaction temperature maintained at 5 to 6° C., 4.0 g of a saturated aqueous NaHCO3 solution was added dropwise with the inner temperature maintained at 10° C. or less and, after completion of the dropwise addition, the mixture was allowed to stand still for 30 minutes. The organic layer (upper layer) formed was separated and the aqueous layer (lower layer) was extracted twice with 4.0 g of isopropyl ether. All the separated organic layers were combined, washed with 4.0 g of distilled water, and the organic layer was concentrated under reduced pressure to obtain 2.29 g of a concentrate. The concentrate was dissolved in 10 g of hexane at 30° C. and the solution was cooled to −10° C. at a rate of 10° C./hour. The crystals which precipitated were separated by filtration and the crystals obtained were dried under vacuum (26.7 Pa) at 30° C. for 2 hours to obtain 1.10 g (purity 97.0%, 3.93 mmol, yield: 46.2%) of 4-methyltetrahydropyran-4-yl (2-methacryloyloxyethyl)carbamate.

Provenance & Evidence