p-Toluenesulfonic acid → 1,1-Dimethylethyl 4-(1-acetyl-1H-indol-3-yl)-1-piperazinecarboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Into a 150 mL sealed tube was placed a solution of 1-acetyl-1H-indol-3-yl acetate (2.5 g, 11.51 mmol) in toluene (80 mL). To this was added tert-butyl piperazine-1-carboxylate (10.71 g, 57.55 mmol). To the mixture was added p-toluenesulfonic acid (400 mg, 2.33 mmol). The resulting solution was allowed to react, with stirring, overnight while the temperature was maintained at 120° C. in a bath of oil. The reaction progress was monitored by TLC (ethyl acetate/petroleum ether=1:1). The mixture was concentrated by evaporation under vacuum using a rotary evaporator. The resulting solution was diluted with 200 mL of ethyl acetate. The resulting mixture was washed 3 times with 200 mL of NaCl(aq.). The mixture was dried over Na2SO4. The residue was purified by eluting through a column with a 10:1 petroleum ether/ethyl acetate solvent system. This resulted in 2.9 g (72%) of tert-butyl 4-(1-acetyl-1H-indol-3-yl)piperazine-1-carboxylate as a purple solid.

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