反应详情

A solution of 24.7 g (0.25 mol) of phosgene in about 150 ml of ethyl acetate is added dropwise to a solution of 99.7 g (0.5 mol) of 4-acetoxy-2,2,6,6-tetramethylpiperidine in 400 ml of ethyl acetate at 20°-22° in the course of 6 hours, with stirring. After the reaction mixture has been stirred for another 2 hours at room temperature, 63 ml (0.6 mol) of diethylamine are added dropwise in the course of about 30 minutes. The reaction mixture is stirred at room temperature for another 14 hours and is filtered and the salt residue is washed thoroughly with hexane. The combined filtrates are washed twice with water, three times with ice-cold N hydrochloric acid and again with water and dried over sodium sulfate and the solvent is distilled off in a vacuum rotary evaporator. The crude product is recrystallised from diisopropyl ether to give pure 1-diethylcarbamoyl-4-acetoxy-2,2,6,6-tetramethylpiperidine (Compound No. 1) of melting point 58° -60°.

1. stirringAfter the reaction mixture has been stirred for another 2 hours at room temperature
2. stirringThe reaction mixture is stirred at room temperature for another 14 hours
3. filtrationis filtered
4. washthe salt residue is washed thoroughly with hexane
5. washThe combined filtrates are washed twice with water, three times with ice-cold N hydrochloric acid and again with water
6. dry with materialdried over sodium sulfate
7. distillationthe solvent is distilled off in a vacuum rotary evaporator
8. customThe crude product is recrystallised from diisopropyl ether