[CH3:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([NH2:9])=[C:4]([NH2:10])[CH:3]=1.C(N(C(C)C)CC)(C)C.[N+:20]([C:23]1[C:24]([C:28](Cl)=[O:29])=[N:25][NH:26][CH:27]=1)([O-:22])=[O:21]>ClCCl>[NH2:9][C:5]1[CH:6]=[C:7]([CH3:8])[C:2]([CH3:1])=[CH:3][C:4]=1[NH:10][C:28]([C:24]1[C:23]([N+:20]([O-:22])=[O:21])=[CH:27][NH:26][N:25]=1)=[O:29]Method A A stirred solution of 4,5-dimethylphenylenediamine (4.32 g) and diisopropylethylamine (30 ml) in dichloromethane (200 ml) was treated with 4-nitropyrazole-3-carboxylic chloride (5 g) portionwise at 0° C. The reaction mixture was warmed to ambient temperature and stirred for 30 minutes. The solvent was removed in vacuo and the oily residue was partitioned between ethyl acetate and water. The organic layer was dried over magnesium sulfate and concentrated. The residual oil was re-crystallised from ethyl acetate and methanol (10%) to give 4-nitro-1H-pyrazole-3-carboxylic acid (2-amino-4,5-dimethylphenyl)amide (6.58 g) as an orange solid. LC-MS (METHOD B): RT=2.36 minutes, 276.09 (M+H)+.
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