The inhibitory effect of thiourea-based compounds was evaluated using carbon steel body specimens in hydrochloric acid media. Thiourea derivatives, N-(pyrimidin-2-ylcarbamothioyl)benzamide and N-(6-methylpyridin-2-ylcarbamothioyl)benzamide, were synthesized using a simple route with good yields of approximately 70%. The inhibitory efficiencies were obtained by means of weight-loss experiments and electrochemical techniques (e.g. polarization curves and electrochemical impedance spectroscopy). The presence of a methyl functional group showed a better inhibitory efficiency compared with the derivate inhibitor without such modification. Analyzing Langmuir isotherms, G 0 ads values indicate the chemical Downloaded by [University of Sherbrooke] at 15:32 12 April 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 adsorption of thiourea-based compounds. The E Corr values obtained for the thiourea derivative with the methyl functionality was cathodically shifted by approximately −0.08 V, with an inhibition efficiency of 81%.
Corrosion inhibitors have been used to preserve the integrity of metal components of plant facilities under severe corrosive conditions that would lead to failure or reduction of the operating cycle of essential units. These include risers, columns, wells, pipelines, pressure vessels and distillation towers structures. Several compound classes have been studied as corrosion inhibitors for metallic materials. In special, organic compounds have been tested and applied industrially as corrosion inhibitors due to their low toxicity. Taking into account recent recommendations for eliminating the use of toxic inorganic inhibitors there was a significant increase in studies on the use of natural products as corrosion inhibitors. Natural products are considered environmentally suitable corrosion inhibitors for use on a large scale. Recent studies have shown that black pepper extract is rich in a mixture of alkaloids substances that have excellent anti-corrosion properties in acid conditions. The aim of this study was to investigate the carbon steel corrosion inhibition efficiency of black pepper crude extract and purified piperine (major alkaloid present in the extract) in highly corrosive environment by weight loss measurements. For this reason, weight loss tests were carried out to study the inhibition efficiency. The inhibition efficiencies of different concentrations of the black pepper crude extract was higher than the efficiencies of the same concentrations of pure piperine. The efficiencies were about 97 % for the crude extract and 70 % for the pure piperine.
Quinazolinones have pharmacological effects on vascular reactivity through different mechanisms. We synthesized 4-phenylquinazolin-2(1H)-one derivatives under microwave irradiation and tested them on the rat thoracic aorta. The prepared compounds 2a–2f were obtained in about 1 h with suitable yields (31–92%). All derivatives produced vasorelaxant effects with IC50 values ranging from 3.41 ± 0.65 µM to 39.72 ± 6.77 µM. Compounds 2c, 2e and 2f demonstrated the highest potency in endothelium-intact aorta rings (IC50 4.31 ± 0.90 µM, 4.94 ± 1.21 µM and 3.41 ± 0.65 µM respectively), and they achieved around 90% relaxation (30 μM). In aorta rings without an endothelium, the effect of compound 2f was abolished. Using the MTT assay to test for cell viability, only compound 2b induced cytotoxicity at the maximum concentration employed (30 µM). The results show that vasorelaxation by 4-phenylquinazolin-2(1H)-one derivatives might depend on the activation of a signalling pathway triggered by endothelium-derived factors.
Background:
Many contagious diseases have been caused by a variety of nontuberculous mycobacteria, opportunistic pathogens that can cause disseminated or localized diseases, particularly pulmonary, skin, and soft tissue infections.
Objective:
In this study fifty five substituted 4-N-alkylated-2-trifluoromethylquinoline were evaluated against five species of nontuberculous mycobacteria: Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium abscessus, Mycobacterium kansasii, and Mycobacterium avium.
Methods:
The antimycobacterial activities of all tested compounds were assessed using the microplate procedure with broth microdilution assay. The most actives were selected for their potential cytotoxic activity against Vero cells.
Results:
Most of the compounds displayed some activity against M. kansaii, of which 12, 15, 34, 37 and 48 were the most active at 3.12 g/mL. The derivative 8 was the most active against M. fortuitum at 6.25 g/mL and the most active against M. chelonae at 3.12 g/mL. The derivative 2 was the most active against M. avium at 12.5 g/mL, and 9 the most active against M. abscessus at 12.5 g/mL. All the most active compounds showed MIC values similar to the references drugs used against these species.
Conclusion:
47 compounds displayed some activity against some of the species analyzed, highlighting derivatives 12, 15, 34, 37, and 48, which presented the lower MIC values. Compounds 34 and 37 displayed the highest activity and not showed cytotoxicity against Vero cells. These findings open new perspectives for the research of new drugs against these mycobacterial species based on the quinoline nucleus.
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