反应详情

A solution of tert-butyl 4-(aminooxy)piperidine-1-carboxylate (2.0 g, 9.2 mmol) in tetrahydrofuran (10 ml) was added over 30 minutes to a suspension of trichloromethyl chloroformate (2.74 g, 13.8 mmol) and activated charcoal (20 mg) in tetrahydrofuran (35 ml) at 0° C. over 30 minutes. After stirring at room temperature for 17 hours, the reaction mixture was filtered over silicagel and the filtrate was concentrated in vacuo. The residue was dissolved in tetrahydrofuran (15 ml), 4-fluoroaniline (2.0 g, 18.4 mmol) and N,N-diisopropylethylamine (3.58 g, 27.6 mmol) were added and the whole was stirred at room temperature for 17 hours. The reaction mixture was concentrated in vacuo and the residue was diluted with ethyl acetate (50 ml), washed with H2O (20 ml×2), brine (20 ml×2), dried over Na2SO4 and concentrated in vacuo. The residual solid was recrystallized from diethyl ether to give tert-butyl 4-(3-(4-fluorophenyl)ureidooxy)piperidine-1-carboxylate (2.19 g, 67%) as a white solid: LCMS: 354 [M+1]+.

1. filtrationthe reaction mixture was filtered over silicagel
2. concentrationthe filtrate was concentrated in vacuo
3. dissolutionThe residue was dissolved in tetrahydrofuran (15 ml)
4. stirringthe whole was stirred at room temperature for 17 hours
5. concentrationThe reaction mixture was concentrated in vacuo
6. additionthe residue was diluted with ethyl acetate (50 ml)
7. washwashed with H2O (20 ml×2), brine (20 ml×2)
8. dry with materialdried over Na2SO4
9. concentrationconcentrated in vacuo
10. customThe residual solid was recrystallized from diethyl ether