Synthesis and biological evaluation of new 4-oxo-thiazolidin-2-ylidene derivatives as antimicrobial agents.

In this study, an efficient synthesis and the antimicrobial activity evaluation of some 4-oxo-thiazolidin-2-ylidene derivatives are presented. The structures of the target substances were confirmed by using 1 H and 13 C nuclear magnetic resonance spectroscopy, mass spectrometry, infrared spectroscopy, and elemental analysis. The synthesized compounds were evaluated for antimicrobial activity against five bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus) and two fungal strains (Candida albicans and Cryptococcus neoformans). It was shown that the compounds in this series possess antibacterial and antifungal activities.

A New Reagent for Spectrophotometric Determination of Ir(IV): 5-[2-(4-Hydroxyphenyl) hydrazineylidene]- 4-iminothiazolidin-2-one (HPIT).

The paper presents a new azolidone derivative - 5-[2-(4-hydroxyphenyl)hydrazineylidene]-4-iminothiazolidin-2-one (HPIT) studies and its interaction results with iridium(IV) ions. The Ir(IV) with this reagent in the pH = 5.0 without heating forms a stable complex (?max = 328 nm). The stoichiometric ratio of Ir(IV) to the reagent in complex is 1:1. The molar absorptivity and Sandell's sensitivity are 5.57×103 L mol-1 cm-1 and 0.034 µg cm-2 respectively. The calibration curve is linear in the range of 1.0-11.5 µg mL-1 of Ir(IV) (R = 0.9996). The limit of detection is 0.4 µg mL-1. Based on the conducted investigation a rapid and simple, spectrophotometric method for the determination of Ir(IV) using 5-[2-(4-hydroxyphenyl)hydrazineylidene]-4-iminothiazolidin-2-one as a chromophoric reagent was developed. The iridium(IV) was determined in various synthetic mixtures and alloys.

Spectrophotometric Determination of Ru(IV) Using 5-Hydroxyimino-4-imino-1,3-thiazolidin-2-one as a Novel Analytical Reagent.

The interaction of Ru(IV) ions with a novel analytical reagent - 5-hydroxyimino-4-imino-1,3-thiazolidin-2-one, by spectrophotometric method was investigated. The complex is formed at pH 5.0 in acetate buffer medium after heating in the boiling water bath (~371 K) for 25 min. The complex has maximum absorption at 350 nm and is stable for 24 h. Beer's law is valid over the concentration range of 0.5-6.1 µg mL-1 for Ru(IV). The molar absorptivity at µ = 350 nm is 6.21 × 103 L mol-1 cm-1. The limit of detection of this method is 0.2 µg mL-1. The interfering effect of various cations and anions on the spectrophotometric determination of the Ru(IV) were investigated. The proposed method was successfully applied to the determination of Ru(IV) in alloys.

Spectrophotometric studies of 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)-hydrazino]-benzenesulfonic acid as a reagent for the determination of palladium.

The spectrophotometric behavior of a new, first-time synthesized reagent - 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)hydrazino]-benzenesulfonic acid (ITHBA), has been investigated. A simple, rapid, accurate, selective and sensitive method for the spectrophotometric determination of Pd(II) ions using this reagent was developed. The optimal conditions for the formation of the complexes were found. The molar absorptivity at λ = 438 nm is 7.5 × 10(3) L mol(-1) cm(-1), and Beer's law is observed for the concentrations ranging from 0.2-2.2 µg mL-1Pd(II). The effects of extraneous ions were investigated. The method proved to be successful in determination of palladium in the intermetallides and resistor. The accuracy of spectrophotometric palladium assay in real objects with 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)-hydrazino]-benzenesulfonic acid has been confirmed by voltammetric or atomic absorption spectroscopy method.