Trifluoroacetic acid → Ethyl 4-(2-(piperazin-1-yl)phenoxy)butanoate
Reaktionsgleichung
O=C1CCC2C(=CC(OCCCC[N:17]3[CH2:22][CH2:21][N:20]([C:23]4[CH:38]=[CH:37][CH:36]=[CH:35][C:24]=4[O:25][CH2:26][CH2:27][CH2:28][C:29]([O:31][CH:32](C)[CH3:33])=[O:30])[CH2:19][CH2:18]3)=CC=2)N1.FC(F)(F)C(O)=O>C(Cl)Cl>[N:20]1([C:23]2[CH:38]=[CH:37][CH:36]=[CH:35][C:24]=2[O:25][CH2:26][CH2:27][CH2:28][C:29]([O:31][CH2:32][CH3:33])=[O:30])[CH2:19][CH2:18][NH:17][CH2:22][CH2:21]1Komponenten
4
Versuchsvorschrift
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+).