Part B: A mixture of the crude lithium 1-(4-chlorophenyl)-2-(2,4-dichlorophenyl)-4,5-dihydro-1H-imidazole-4-carboxylate (1.0 gram, ˜0.0027 mol), benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP) (1.2 gram, 0.0027 mol), 1-aminopiperidine (0.3 gram, 0.003 mol) and triethylamine (1 ml) in DMF (30 ml) is stirred at room temperature for 16 hours. After concentration in vacuo, water is added and the resulting mixture is extracted (2×) with dichloromethane. The dichloromethane layers are collected, dried over MgSO4, filtered and concentrated in vacuo to give a residue that is further purified by flash chromatography (silicagel, dichloromethane/methanol=95/5 (v/v)) to give 1-(4-chlorophenyl)-2-(2,4-dichlorophenyl)-N-(piperidin-1-yl)-4,5-dihydro-1H-imidazole-4-carboxamide (380 mg, 31% yield). Melting point: 113-116° C. 1H-NMR (200 MHz, CDCl3): δ 1.33-1.48 (m, 2H), 1.60-1.80 (m, 4H), 2.68-2.82 (m, 4H), 4.28-4.35 (m, 2H), 4.84 (dd, J=11 and 9 Hz, 1H), 6.65 (br d, J=8 Hz, 2H), 7.11 (br d, J=8 Hz, 2H), 7.23-7.33 (m, 2H), 7.41 (d, J=2 Hz, 1H), 7.57 (br s, 1H).
