A mixture of tert-butyl 4-(5-acetyl-4-phenyl-1H-imidazol-1-yl)piperidine-1-carboxylate [C24, prepared according to the general procedure for the synthesis of tert-butyl 3-[5-acetyl-4-(4-fluorophenyl)-1H-imidazol-1-yl]azetidine-1-carboxylate (C3) in Example 1, except that tert-butyl 4-aminopiperidine-1-carboxylate was used in place of tert-butyl 3-aminoazetidine-1-carboxylate, and 1-{[isocyano(phenyl)methyl]sulfonyl}-4-methylbenzene (C21) was employed rather than 1-fluoro-4-{isocyano[(4-methylphenyl)sulfonyl]methyl}benzene (C2)] (414 mg, 1.12 mmol) and N,N-dimethylformamide dimethyl acetal (4 mL) was heated to 100° C. for 18 hours, then cooled and concentrated in vacuo. The residue was dissolved in anhydrous methanol (2 ml) and added to a solution of N-methylguanidine in methanol [prepared by reacting sodium metal (70 mg, 3 mmol) with anhydrous methanol (2 mL), then adding N-methylguanidine hydrochloride (413 mg, 3.77 mmol) to the resulting sodium methoxide solution]. The reaction mixture was heated at 50° C. for 21 hours, then cooled to room temperature and treated with water (1 mL). The solids were collected by filtration, rinsed with saturated aqueous sodium bicarbonate solution and water and dried to provide the product as a light tan solid. Yield: 230 mg, 0.53 mmol, 47%. APCI m/z 435.0 (M+1). 1H NMR (400 MHz, CDCl3) δ 1.49 (s, 9H), 1.82-1.93 (m, 2H), 2.19 (br d, J=12 Hz, 2H), 2.73-2.82 (m, 2H), 3.06 (d, J=5.1 Hz, 3H), 4.26-4.35 (m, 2H), 4.81-4.90 (m, 1H), 5.16-5.21 (m, 1H), 6.45 (d, J=5.1 Hz, 1H), 7.28-7.34 (m, 3H), 7.48-7.51 (m, 2H), 7.75 (s, 1H), 8.15 (br d, J=4.9 Hz, 1H).
