[NH2:1][C:2]1[NH:6][N:5]=[CH:4][C:3]=1[C:7]#[N:8].[CH3:9][O:10][C:11]1[CH:18]=[C:17]([O:19][CH3:20])[CH:16]=[CH:15][C:12]=1[CH:13]=O.[CH:21]([N+:24]#[C-:25])([CH3:23])[CH3:22].Cl(O)(=O)(=O)=O>CO>[CH3:9][O:10][C:11]1[CH:18]=[C:17]([O:19][CH3:20])[CH:16]=[CH:15][C:12]=1[C:13]1[NH:1][C:2]2[N:6]([C:25]=1[NH:24][CH:21]([CH3:23])[CH3:22])[N:5]=[CH:4][C:3]=2[C:7]#[N:8]To a mixture of 5-amino-1H-pyrazole-4-carbonitrile (771 mg, 7.13 mmol) and 2,4-dimethoxybenzaldehyde (1.19 g, 7.13 mmol) in a vial under nitrogen atmosphere were added methanol (20 mL) followed by iso-propyl isonitrile (500 mg, 581 μL, 7.13 mmol) and perchloric acid (143 mg, 128 μL, 1.43 mmol) at RT. Then, the resulting brown solution was stirred for 15 h by which time LC/MS analysis indicated the presence of the desired product. Then, the solvent was removed under vacuum and the residue was purified using an ISCO (80 g) column chromatography eluting with 0-50% ethyl acetate in hexanes. The desired fractions were combined and the solvent was removed under vacuum to obtain 647 mg (28% yield) of 2-(2,4-dimethoxyphenyl)-3-(iso-propylamino)-1H-imidazo[1,2-b]pyrazole-7-carbonitrile as a light yellow solid. LC/MS calcd. for C17H19N5O2 (m/e) 325.37, obsd. 326.0 (M+H, ES+).
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