Studies on heterocyclic compounds: 1,3-thiazolidin-4-one derivatives. III. Biological activity of halogenated 2,3-diaryl-1,3-thiazolidin-4-ones.

In previous communications from these laboratories, thiazolidinone derivatives of general formula (A) were synthesized and screened for antimicrobial activity. (formula; see text) where: X = H, CH3 Ar = phenyl Ar' = fluorinated or chlorinated phenyl The present communication is in part concerned with further extension of these studies to variously halogenated thiazolidinones of general formula (B). (formula; see text) where: X = H, CH3 R = H, 2-F, 3-F, 4-F, 3-Cl, 4-Cl R' = H, 4-F, 4-Cl These compounds were prepared by the general synthetic procedure previously reported for the 1,3-thiazolidin-4-one derivatives already prepared and screened in this SARs program. The general synthetic approach involves the cyclocondensation of the appropriate Schiff bases with alpha-mercaptoalkanoic acids such as thioglycolic and thiolactic acid. The prepared compounds were tested for their possible activity by a disk-diffusion assay (Kirby-Bauer modified). The organisms used were: S. aureus, S. beta-haemoliticus, B. subtilis, M. paratuberculosis 607, S. typhi, Kl. pneumoniae, E. coli Bb, Ps. aeruginosa, C. albicans, A. niger, S. cerevisiae. The results of this antimicrobial screening showed that the prepared compounds exhibited varying degrees of activity against Gram-positive, Gram-negative bacteria, and fungi. The second half of this report deals with the structure-activity relationships in all the compounds prepared and studied in this research program. For comparison of antimicrobial activity, the growth inhibitory activity of all the halogenated thiazolidinones of type (A) and (B), prepared and screened in this SARs study, were tabulated.(ABSTRACT TRUNCATED AT 250 WORDS)