[Br:1][C:2]1[N:7]=[C:6]([C:8](=O)[CH2:9][C:10]#[N:11])[CH:5]=[CH:4][CH:3]=1.[CH3:13][NH:14][NH2:15]>C(O)C>[Br:1][C:2]1[N:7]=[C:6]([C:8]2[N:14]([CH3:13])[N:15]=[C:10]([NH2:11])[CH:9]=2)[CH:5]=[CH:4][CH:3]=1To a solution of 3-(6-bromo-2-pyridyl)-3-oxo-propanenitrile (1.71 g, 7.6 mmol, Preparation A.1) in ethanol (50 mL) was added methyl hydrazine (1.20 mL, 22.8 mmol). The resulting mixture was stirred for about 30 min at rt and then heated under reflux for about 4 h. After cooling to rt the reaction mixture was concentrated in vacuo. The residue was purified by column chromatography (SiO2, ethyl acetate/hexanes 1:2) to give 3-(6-bromo-2-pyridyl)-2-methyl-pyrazol-5-amine (1.56 g, 6.2 mmol, 81%) as an off white solid: 1H-NMR (CDCl3, Bruker 400 MHz) δ 3.57 (2 H, br s); 3.75 (3 H, s); 5.90 (1 H, s); 7.34 (1 H, d, J=8 Hz); 7.52 (1 H, t, J=8 Hz); 7.82 (1 H, d, J=8 Hz).
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