A mixture of 1-(3,4-dimethylphenyl)-3-methyl-4-(3-bromo-2-methoxyphenyl)hydrazono-5-pyrazolone (5 g) prepared as in Example 2, and 3-carboxyphenylboronic acid (2.99 g), bis(triphenylphosphine)palladium(II)chloride [PdCl2(PPh3)2] (0.42 g), potassium hydroxide (1.74 g) in ethanol. (250 mL) and water (30 mL) was heated to about reflux temperature and stirred for about 24 hours. The hot mixture was filtered to remove the catalyst. The clear filtrate was concentrated under vacuum. To the residue, water (100 mL) was added; acidified to pH 3-5 using hydrochloric acid and stirred for about 30 minutes at about room temperature. The slurry was filtered to give a yellowish orange solid product, which was washed with water (50 mL) and dried in an oven at about 55° C. to about 60° C. for about 12 hours.
