Synthesis of New Thiazole Derivatives Bearing Thiazolidin-4(5H)-One Structure and Evaluation of Their Antimicrobial Activity

The first report about antimicrobial resistance was published in the 1940s. And today, the antimicrobial resistance has become a worldwide problem. Because of this problem, there is a need to develop new drugs. That's why we synthesized some novel thiazolidine-4-one derivatives and evaluated their antimicrobial activity. The final compounds were obtained by reacting 2-[(4,5-diphenylthiazol-2-yl)imino]thiazolidin-4-one with some aryl aldehydes. The synthesized compounds were investigated for their antimicrobial activity against four Candida species, five gram-negative and four gram-positive bacterial species. The lead compounds (4a- h) were obtained with a yield of at least 70%. All compounds showed antimicrobial activity. Compound 4f (MIC: 31.25 µg/ml) exhibited more efficacy than the other compounds against C. glabrata (ATCC 24433). Compound 4b (MIC: 62.5 µg/ml) was the most active compound against all bacterial species, particularly K. pneumoniae (NCTC 9633). Whereas, compound 4c (MIC: <31.25 µg/ml) was observed as the most active compound against E. coli (ATCC 25922). In general, all compounds (4a-4h) showed antimicrobial activity against all fungi and bacterial species. Compounds 4b (2,6-dichlorobenzylidene), 4c (2,6-dihydroxybenzylidene), 4f (1H-pyrrol-2- yl)methylene), 4g (4-triflouromethylbenzylidene) and 4h (2,3,4-trimethoxybenzylidene) were determined as the most active compounds

Synthesis and antibacterial activity of novel 2-(arylimino)thiazolidin-4-one and 2-(benzylidenehydrazono)-3-arylthiazolidin-4-one derivatives.

The ongoing spread of multidrug-resistant bacteria demands an intensive search for new antibacterial agents. In the present study, a series of new 1,3-thiazolidin-4-ones has been synthesized and investigated for its in vitro antibacterial activity. The most potent antibacterial compound 4c was found to be active, at low micromolar range, against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and the pneumonic plague causative agent Yersinia pestis with minimum inhibitory concentrations of 5 μM, 2.5 μM, 2.5 μM and 5 μM, respectively. Compound 4c showed the ability to kill E. faecalis JH212 strain with a minimum bactericidal concentration of 5 μM. Furthermore, compounds 9b and 10a inhibited the biofilm formation in S. epidermidis, where they showed 70% to 80% inhibition at a concentration of 40 μM.

Synthesis and antimicrobial evaluation of novel 3-(4,6- diphenyl-6H-1,3-thiazin-2-yl)-2-(4-methoxyphenyl) thiazolidin-4-one derivatives.

A novel series of potentially biologically active 3-(4,6-diphenyl-6H-1,3-thiazin-2-yl)-2-(4-methoxyphenyl) thiazolidin-4-one derivatives (5a-5k) have been synthesized by the condensation-cyclization reaction of 4,6- diphenyl-6H-1,3-thiazin-2-amine, aromatic aldehyde and thioglycolic acid in polypropylene glycol at 1100C temperature. The structure of the newly synthesized compounds has been established on the basis of their spectral data and elemental analysis. The antimicrobial activity of the synthesized compounds were tested in vitro against the sensitive organisms Staphylococcus aureus, Bacillus subtilis as a Gram positive bacteria and Escherichia coli, Pseudomonas aeruginosa as a Gram negative bacteria and two pathogenic fungal strains Candida albicans, Aspergillus niger by using the disc diffusion method. The detailed synthesis, spectroscopic data, and antimicrobial screening of synthesized compounds were reported.