Reaction Steps
A solution of piperidine-1,4-dicarboxylic acid mono-tert-butyl ester (AMR01030, 417 mg, 1.82 mmol) in dry DCM (8 mL) was stirred under nitrogen, and 4-dimethylaminopyridine (DMPA, 40 mg, 0.327 mmol), (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 1.05 g, 5.46 mmol) and triethylamine (0.25 mL) were added. The resulting mixture was stirred for 30 min under nitrogen and 2-(4-chloro-phenoxy)-phenylamine (AMR01029, 400 mg, 1.82 mmol) in dry DCM (4 mL) was added. After stirring at room temperature for 24 h, the mixture was diluted with DCM, washed with HCl 1M (3×25 mL), water, saturated NaHCO3 (2×25 mL) and brine. The organic layer was dried (MgSO4), filtered and evaporated. Flash chromatography on silica gel of the crude product using hexane/EtOAc 8:2 as eluent gave starting material (104 mg). Further elution using hexane/EtOAc 7:3 gave 4-[2-(4-chlorophenoxy)-phenylcarbamoyl]piperidine-1-carboxylic acid tert-butyl ester (430 mg, 55%) as a white solid, mp 97-99° C. Rf: 0.22 (hexane/EtOAc 7:3) LC/MS (APCI) tr=3.83 min, m/z 431.23 (33), 429.21 (M−−H, 100). 1H NMR (270 MHz, CDCl3) δ 1.44 (9H, s, 3CH3), 1.68 (2H, m, CH2), 1.83 (2H, m, CH2), 2.36 (1H, tt, J=11.4, 3.7 Hz), 2.75 (4H, br t, 2CH2), 4.11 (4H, m, 2CH2), 6.81 (1H, dd, J=8.2, 1.5 Hz, ArH), 6.93 (2H, AA′BB′, ArH), 7.01 (1H, td, ArH), 7.12 (1H, td, ArH), 7.31 (2H, AA′BB′, ArH), 7.68 (1H, br s, NH) and 8.40 (1H, dd, J=6.9, 1.5 Hz, ArH).
