Synthesis and antimicrobial activity of novel arylideneisothiosemicarbazones

Synthesis of Some New 1,3,4-Thiadiazole, Thiazole and Pyridine Derivatives Containing 1,2,3-Triazole Moiety

In this study, 1-(5-Methyl-1-(p-tolyl)-1H-1,2,3-triazol-4-yl)ethan-1-one, was reacted with Thiosemicarbazide, alkyl carbodithioate and benzaldehyde to give thiosemicarbazone, alkylidenehydrazinecarbodithioate and 3-phenylprop-2-en-1-one-1,2,3-triazole derivatives. The 1,3,4-thiadiazole derivatives containing the 1,2,3-triazole moiety were obtained via reaction of alkylidenecarbodithioate with hydrazonoyl halides. Also, hydrazonoyl halides were reacted with thiosemicarbazone and pyrazolylthioamide to give 1,3-thiazoles derivatives. Subsequently, 3-phenyl-2-en-1-one was used to synthesize substituted pyridines and substituted nicotinic acid ester. The latter was converted to its azide compound which was reacted with aromatic amines and phenol to give substituted urea and phenylcarbamate containing 1,2,3-triazole moiety. The newly synthesized compounds were established by elemental analysis, spectral data and alternative synthesis whenever possible.

Exploring the thiazole scaffold for the identification of new agents for the treatment of fluconazole resistant Candida

Cyclohexyliden- and 2-methylcyclohexyliden-hydrazo-4-arylthiazoles were synthesized and tested as antifungal agents. All compounds exhibited minimal inhibitory concentration (MIC) values comparable with those of fluconazole (FLC). Moreover, some compounds showed fungicidal activity at low concentration. Worth noting five out of nine compounds were active towards Candida albicans 25 FLC resistant isolated from clinical specimens. The cellular toxicity was evaluated and none of the compounds is toxic at the MIC. On the basis of our data we can conclude that these derivatives are promising agents for the treatment of resistant C. albicans.

Synthesis, characterization and antidiabetic properties of N(1)-2,4-dihydroxybenzylidene-N(4)-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato-oxovanadium(IV)

A new oxovanadium(IV) chelate [VOL] (L: N(1)-2,4-dihydroxybenzylidene-N(4)-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato) was synthesized and characterized by elemental analysis, conductivity and magnetic measurements, UV-vis, IR, EPR spectroscopy and mass spectrometry. The biochemical and immunohistochemical effects of the administration of the vanadium complex (VOL) into the pancreas of normal and streptozotocin-induced diabetic rats were profoundly investigated. The animals were randomly divided into four groups. Group I: control (intact) animals. Group II: control animals administered with VOL. Group III: STZ-induced diabetic animals. Group IV: STZ-induced diabetic animals administered with VOL. VOL was given to some of the experimental animals by gavage at a dose of 0.2mM/kg every day for 12 days. Blood samples were collected from animals, on 0 and 1, 6 and 12 days after STZ injection. On day 12, the pancreatic tissues were taken from the animals. The tissue sections were labelled with streptavidin biotin peroxidase technique for insulin. In the diabetic group, the blood glucose levels, aspartate and alanine transaminases, alkaline phosphatase activities were increased. But, in the diabetic+VOL groups, the blood glucose levels, aspartate and alanine transaminases, alkaline phosphatase activities were reduced. In the diabetic group, a decrease in the pancreatic glutathione levels, glutathione peroxidase and superoxide dismutase activities and an increase in the pancreatic lipid peroxidation level and catalase activities were observed. The administration of VOL to the diabetic rats reversed this diabetic effect due to its insulinomimetic effects. According to the immunohistochemical and biochemical results obtained, it was concluded that VOL can regenerate B cells of the pancreas in experimental diabetes and has an antidiabetic and protective effects on the pancreas.

Antimicrobial activity of a series of thiosemicarbazones and their ZnII and PdII complexes

Thirty-four thiosemicarbazones and S-alkyl thiosemicarbazones, and some of their Zn(II) and Pd(II) complexes were obtained and purified to investigate antimicrobial activity. MIC values of the compounds were determined by the disc diffusion method against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Staphylococcus aureus, S. epidermidis, and Candida albicans. The thiosemicarbazones show antibacterial and antifungal effects in free ligand and metal-complex form. Picolinaldehyde-S-methyl- and -S-benzylthiosemicarbazones did not affect the tested microorganisms but their Zn(II) complexes showed selective activity. The antimicrobial activity is relatively high in Me2SO, but the antimicrobial potential is changed in a certain range with Me2SO, HCONMe2, EtOH and CHCl3.

Synthesis and anti-microbial activity evaluation of some new 1-benzoyl-isothiosemicarbazides

The synthesis of some aroylisothiosemicarbazides was accomplished and their biological activity against bacteria, fungi, and mycobacteria was investigated. Different synthetic pathways were followed according to the kind of substituents that were introduced on both the aroyl ring and the sulfur atom. Anti-bacterial activity was measured against Staphylococcus aureus, S. epidermidis, Streptococcus agalactiae and S. faecalis, Escherichia coli, and Salmonella typhi, while antifungal activity was evaluated against C. albicans. Two species, Mycobacterium tuberculosis H37RV and Mycobacterium avium ATCC19421, were employed to evaluate antimycobacterial activity.

An investigation of the biological effect of structural modifications of isothiosemicarbazones and their cyclic analogues

Several arylideneisothiosemicarbazones and arylidenehydrazothiazoles have been synthesised to obtain new antimicrobial agents. Their activity against both bacteria and fungi has been tested and some interesting informations about their biological activity have been obtained.

Synthesis and anti-microbial activity of isothiosemicarbazones and cyclic analogues

It is known that some derivatives of both thiourea and thiosemicarbazide exhibit potent anti-microbial activity. In order to investigate the effects on the biological properties of structural modifications of such structures, we have synthesised and studied some arylidenisothiosemicarbazones. In this paper we report on the synthesis and structure-activity relationships of some isothiosemicarbazones, where the arylidene group has been replaced with a cycloalkyl group and the sulfur atom has been either differently substituted or enclosed in a thiazole ring.

Synthesis and antimycobacterial activity of new S-alkylisothiosemicarbazone derivatives

A new series of S-alkylisothiosemicarbazones of 3- and 4-pyridincarboxaldehyde and 4-fluoro- and 4-trifluoromethylbenzaldehyde was synthesized and evaluated for biological activity against various Mycobacterium strains. Inhibitory activity against Mycobacterium tuberculosis H37Rv ATCC 27294 and INH-R ATCC 35822 was compared with activity against clinical isolated Mycobacteria as well as against MOTT. Some of newly prepared compounds showed best inhibitory values against clinical isolated Mycobacteria, besides to low citotoxicity values.