Triphosgene → Tert-butyl 4-((3-(2-nitro-5-(thiophen-2-yl)phenyl)ureido)methyl)piperidine-1-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a solution of 2-nitro-5-(thiophen-2-yl)aniline (0.60 g, 2.72 mmol, 1.0 equiv.) in dichloromethane at 0° C. were added TEA (5 mL, 35.4 mmol, 13 equiv.) and triphosgene (0.81 g, 2.72 mmol, 1.0 equiv.). The mixture was warmed to room temperature and stirred 3 h. The reaction was then cooled to 0° C. and tert-butyl 4-(aminomethyl)piperidine-1-carboxylate (0.88 g, 4.09 mmol, 1.5 equiv.) was then added slowly. The reaction mixture was slowly warmed to room temperature and stirred for 2 h. The reaction was diluted with dichloromethane, washed with water and brine, dried over anhydrous magnesium sulfate, filtered, and concentrated. The crude residue was purified by column chromatography (silica gel, EtOAc/hexanes) to afford tert-butyl 4-((3-(2-nitro-5-(thiophen-2-yl)phenyl)ureido)methyl)piperidine-1-carboxylate (0.31 g, 25% yield).

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