Conformational properties and in vitro antibacterial activity of some diarylsulphones

The 2-pyridylphenylsulphone, di-2-pyridylsulphone and its p-nitro and p,p'-dinitro derivatives were synthesized and tested for antibacterial activity against a number of gram-positive and gram-negative bacteria. The electric dipole moment of these compounds were also measured (in benzene, 25 degrees) and analyzed in terms of molecular conformation in solution. The derivative compounds bearing a 5-nitro-2-pyridine fragment were found to be the most active in the series examined. Among these the nitro-2-pyridylphenylsulphone was found to have a broad-spectrum effect on gram-positive and gram-negative bacteria. Results of the conformational study in combination with microbiological data allowed discussion on the possible inferences concerning the stereochemical aspects of the interaction of diarylsulphones with bacterial receptor sites.