tert-Butyl 2-[(4-piperidin-4-ylbenzoyl)amino]phenylcarbamate (prepared as described in Method 1 below; 395 mg, 1.0 mmol) and 3-ethyl-1H-pyrazole-4-carbaldehyde (149 mg, 1.2 mmol) were stirred at ambient temperature in dichloromethane (10 ml) for 1 hour. Sodium triacetoxyborohydride (297 mg, 1.4 mmol) was added and the mixture stiffed at ambient temperature for 24 hours. The resulting solution was absorbed onto an SCX-2 column which was washed with methanol (2 column volumes) and then the product eluted with a 2M solution of ammonia in methanol (2 column volumes) to give the product as a white foam. This was purified by chromatography on silica eluting with 10% methanol in dichloromethane. The residue was dissolved in dichloromethane (4 ml) and trifluoroacetic acid (1 ml) was added and the mixture stirred for 3 hours at ambient temperature. The resulting solution was absorbed onto an SCX-2 column which was washed with methanol (2 column volumes) and then the product eluted with a 2M solution of ammonia in methanol (2 column volumes) to give the title compound (232 mg, 75%). NMR Spectrum: (DMSO d6) δ 1.18 (t, 3H), 1.65 (m, 2H), 1.77 (m, 2H), 2.00 (m, 2H), 2.57 (m, 3H), 2.95 (m, 2H), 3.34 (s, 2H), 4.86 (br s, 2H), 6.60 (m, 1H), 6.78 (d, 1H), 6.97 (m, 1H), 7.17 (d, 1H), 7.29 (br s, 1H), 7.37 (d, 2H), 7.91 (d, 2H), 9.55 (s, 1H), 12.39 (s, 1H); Mass Spectrum: M+H+ 404.
