反应详情

To a solution of 301 mg of 3-(3,5-di-tert-butyl-4-hydroxybenzylidene)pyrrolidin-2-one (1.0 mmole) dissolved into 5 ml of DMF, NaH (60% in mineral oil, 85 mg, 2.1 mmole) was added under ice-cooling. The resulting mixture was stirred at room temperature for 30 min, then the solution was cooled again. N,N-Dimethylphenylcarbamate (282 mg, 1.71 mmole) which was prepared according to the method described in J. Org. Chem., p660, 21, 1956, was added thereto, then the resulting solution was stirred at room temperature for 3 hours. The reaction mixture was poured into ethyl acetate, which was washed with 1N-HCl, water, and saturated brine, dried over magnesium sulfate, and evaporated. The obtained residue was separated by using silica gel chromatography (toluene:ethyl acetate=2:1) and recrystallized from ether-n-hexane, whereby 190 mg of the objective compound was obtained in 51% yield. The physical constants are described on Table 1.

1. additionwas added under ice-
2. temperaturecooling
3. temperaturethe solution was cooled again
4. addition, p660, 21, 1956, was added
5. stirringthe resulting solution was stirred at room temperature for 3 hours
6. washwas washed with 1N-HCl, water, and saturated brine
7. dry with materialdried over magnesium sulfate
8. customevaporated
9. customThe obtained residue was separated
10. customrecrystallized from ether-n-hexane