5-[3-(4-Methoxyphenyl)-propyl]-2-(4-methylbenzyl)-4-propyl-2,4-dihydro-[1,2,4]triazol-3-one (0.770 g, 2.03 mmol) and excess pyridine hydrochloride were melted together for 2 hours with stirring at 180° C. After cooling to room temperature, the contents were diluted in ethyl acetate (50 mL) and water (50 mL). The aqueous layer was extracted with ethyl acetate (2×25 mL). The combined organics were washed with 5 N HCl (50 mL), saturated aq. NaCl (25 mL), dried (MgSO4), filtered and concentrated to afford the title compound as a yellow oil (0.670 g, 1.83 mmol, 90%): 1H NMR (DMSO-d6) δ 9.13 (s, 1 H), 7.10 (q, 4H, J=3.0 Hz), 6.79 (AB, 4H, J=8.5 Hz), 4.77 (s, 2H), 2.5 (t, 2H, J=7.5 Hz), 2.46 (t, 2H, J=7.5 Hz), 2.24 (s, 3H), 1.79 (m, 2H), 1.51 (m, 2H), 0.79 (t, 3H, J=7.5 Hz); 13C NMR (DMSO-d6) δ 156.1, 154.1, 146.8, 137.2, 135.1, 132.1, 129.9, 129.7, 128.1, 115.7, 48.3, 42.8, 34.1, 28.2, 24.7, 22.5, 21.3, 11.5; IR (CHCl3) 3007, 2937, 1690, 1515, 1463 cm−1. Exact Mass Calcd. for C22H28N3O2: 366.2182. Found: 366.2191.
