Trifluoroacetic acid → 4-Chlorophenyl 2-(2,3,4,5-tetrahydroazepino[4,5-b]indol-6(1H)-yl)ethyl ether hydrochloride

tert-Butyl 6-[2-(4-chlorophenoxy)ethyl]-1,4,5,6-tetrahydroazepino[4,5-b]indole-3(2H)-carboxylate (0.622 g, 1.41 mmol) was dissolved in CH2Cl2 (10 mL) at rt. CF3CO2H (4 mL) was added, then the reaction mixture was stirred for 1 h. The reaction mixture was concentrated and the residue was taken up in EtOAc and washed with 1 N NaOH. The aqueous layer was extracted with EtOAc, and the combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated. The crude product (0.541 g) was dissolved in EtOAc (2 mL) and 1 N HCl in Et2O (2 mL) was added. The solvents were removed under vacuum and Et2O (10 mL) was added to the residue. The resulting mixture was sonicated and the finely powdered salt was collected by filtration. 4-Chlorophenyl 2-(2,3,4,5-tetrahydroazepino[4,5-b]indol-6(1H)-yl)ethyl ether hydrochloride (0.503 g) was obtained in 94% yield. 1H NMR (300 MHz, CD3OD) δ 3.16-3.20, 3.35-3.50, 4.22, 4.59, 6.76, 7.07, 7.18, 7.18, 7.43, 7.48; MS (ESI+) for C20H21ClN2O m/z 341.0 (M+H)+.