The methylation of zomepirac (2-[5-(4-chlorobenzoyl)-1,4-dimethylpyrrol-2-yl]acetic acid sodium salt) (I) with methyl iodide in DMF gives the expected methyl ester (II), which is condensed with 3,6-dichloropyridazine (III) by means of NaH in DMF yielding 2-[5-(4-chlorobenzoyl)-1,4-dimethylpyrrol-2-yl]-2-(6-chloropyridazin-3-yl)acetic acid methyl ester (IV). The hydrolysis of (IV) with LiOH in methanol/water affords the corresonding lithium salt (V), which is decarboxylated in aqueous HCl yielding 1-(4-chlorophenyl)-1-[5-(6-chloropyridazin-3-yl)-1,3-dimethylpyrrol-2-yl]methanone (VI). Finally, this compound is treated with sodium acetate in refluxing acetic acid.