反应详情

To a solution of tert-butyl 4-(2-(4-ethoxy-4-oxobutoxy)phenyl)piperazine-1-carboxylate 13c (0.5 g) in 1 mL DCM was added 1 mL trifluoroacetic acid. The resulting mixture was stirred at rt for 1 h. The color of the reaction mixture darkened and a gas was evolved. The progress of the reaction was monitored by thin layer chromatography (TLC). The reaction mixture was concentrated on rotavapor and the residue was poured onto a mixture of crushed ice and sodium bicarbonate (NaHCO3). The aqueous layer was extracted with DCM, dried over magnesium sulfate and evaporated the solvent to give ethyl 4-(2-(piperazin-1-yl)phenoxy)butanoate 25. The compound 25 was carried to next step without any further purification. Brown oil, 0.37 g (99%). 1H NMR (400 MHz, CDCl3): δ 1.22 (t, J=7.2 Hz, 3H); 2.13 (quintet, J=6.8 Hz, 2H); 2.51 (t, J=7.2 Hz, 2H); 3.08 (broad s, 8H); 4.02 (t, J=6.0 Hz, 2H); 4.11 (q, J=7.2 Hz, 2H); 6.82-6.97 (m, 4H). MS (ESI): m/z=293.50 (M+H+).

1. concentrationThe reaction mixture was concentrated on rotavapor
2. additionthe residue was poured onto a mixture of crushed ice and sodium bicarbonate (NaHCO3)
3. extractionThe aqueous layer was extracted with DCM
4. dry with materialdried over magnesium sulfate
5. customevaporated the solvent