Synthesis
Example B23: 1-methyl-5-nitro-1H-benzo[d]imidazole (prepared according to the method described in WO 2005/092899; 1.14 g, 6.43 mmol) was dissolved in ethanol (50 ml) and stirred at room temperature under hydrogen (1 atm) atmosphere. 10% Pd/C catalyst (50 wt% water, 1.37 g, 0.643 mmol) was added. After 18 h of reaction, the reaction mixture was filtered through diatomaceous earth and rinsed with ethanol. The filtrates were combined and concentrated to afford the crude product 1-methyl-1H-benzo[d]imidazol-5-amine (1.02 g, 108% yield) as a dark orange oil, which was used directly in the next step of the reaction.1H NMR (400 MHz, DMSO-d6) δ 7.87 (s, 1H), 7.17 (d, J=8.4 Hz, 1H), 6.75 (d, J=2.0 Hz, 1H), 6.59 (dd, J=2.0 and 8.4 Hz, 1H), 4.73 (brs, 2H), 3.69 (s, 3H); MS (ESI) m/z: 148.0 (M+H+). Using a method similar to Example B22, 1-methyl-1H-benzo[d]imidazol-5-amine (0.50 g, 3.4 mmol), NaNO2 (0.28 g, 4.1 mmol), SnCl2-2H2O (2.8 g, 14 mmol), and 4-methyl-3-oxopentanenitrile (0.45 g, 4.1 mmol) were reacted to give the crude product 3-Isopropyl-1-(1-methyl-1H-benzo[d]imidazol-5-yl)-1H-pyrazol-5-amine (0.63 g, 73% yield), as a foam, was used directly in the next step of the reaction.1H NMR (400 MHz, DMSO-d6): δ 8.22 (s, 1H), 7.72 (dd, J=0.40 and 1.2 Hz, 1H), and 7.60 (dd, J=0.40 and 8.4 Hz, 1H), 7.42 (dd, J=2.0 and 8.4 Hz, 1H), 5.32 (s, 1H), 5.08 (brs, 2H), 3.85 (s, 3H), 2.75 (septet, J=6.8 Hz, 1H), 1.16 (d, J=6.8 Hz, 6H); MS ( ESI) m/z: 250.0 (M+H+).
References
[1] Patent: US2008/90856, 2008, A1. Location in patent: Page/Page column 46-47
[2] Patent: US2007/27184, 2007, A1. Location in patent: Page/Page column 20
[3] Journal of Pharmacy and Pharmacology, 1951, vol. 3, p. 420,424
[4] Gazzetta Chimica Italiana, 1955, vol. 85, p. 981,984
[5] Collection of Czechoslovak Chemical Communications, 1989, vol. 54, # 3, p. 713 - 724
