Pyrrolnitrin analogues. IX. Synthesis and biological activity of 1-tolyl-3-nitrophenyl-5-methylpyrazole-4-carboxylic acids and 1-tolyl-3-methyl-5-nitrophenylpyrazole-4-carboxylic acids

The syntheses of all the possible 1-tolyl-3-nitrophenyl-5-methylpyrazole-4-carboxylic acids, 1-tolyl-3-methyl-5-nitrophenylprazole-4-carboxylic acids and of the corresponding carboxylates are reported. Several 1,3- and 1,5-diarylpyrazole derivatives were subjected to in vitro antibacterial screenings. Some acids showed activity against some strains of gram-positive bacteria. The results are discussed on the basis of structure-activity relationships.