To a solution of EDC (4.81 g, 25 mmol), HOBt (3.40 g, 25 mmol) and triethylamine (4.67 g, 46 mmol) in DMF (100 ml) was added 4-nitro-1H-pyrazole-3-carboxylic acid (3.63 g, 23.09 mmol) and 4,5-dimethoxy-benzene-1,2-diamine, dihydrochloride (5.06 g, 20.99 mmol) and the mixture stirred at room temperature overnight. The solvent was removed in vacuo and the resulting solid partitioned between ethyl acetate (50 ml) and sodium bicarbonate (50 ml). A precipitate was formed and removed by filtration. This was washed with water followed by diethyl ether and then azeotroped with methanol and toluene to yield 4-nitro-1H-pyrazole-3-carboxylic acid (2-amino-4,5-dimethoxy-phenyl)-amide (2.35 g, 36%).
