Inhibitive assessment of 1-(7-methyl-5-morpholin-4-yl-thiazolo[4,5-d]pyrimidin-2-yl)-hydrazine as a corrosion inhibitor for mild steel in sulfuric acid solution

In this study, the inhibitive effect of synthesized 1-(7-methyl-5-morpholin-4-yl-thiazolo[4,5-d]pyrimidin-2-yl)-hydrazine (MMTPH) as a new corrosion inhibitor for mild steel in 0.5 M sulfuric acid medium is investigated employing potentiodynamic polarization, electrochemical impedance spectroscopy and linear polarization resistance techniques. The results show MMTPH reduces anodic dissolution, retards the hydrogen evolution reaction and its adsorption follows Langmuir’s adsorption isotherm. Any increase in temperature will in turn increase corrosion current densities; however, the presence of MMTPH hinders the rate. In solutions with inhibitor concentration of 200 ppm, temperature elevations as great as 30° (25–55 °C) result in a drop of about 45 % in inhibition efficiency (99–55 %). Thermodynamic adsorption parameters show that the MMTPH is absorbed by a spontaneous exothermic process and the adsorption mechanism is physical. Quantum chemical method shows that the MMTPH molecules can be directly adsorbed at the steel surface on the basis of donor–acceptor interactions between π-electrons of pyrimidine, N atoms of hydrazine and vacant d-orbitals of iron atoms.     

Synthesis of 14-Aryl-14H-7-thiadibenzo[a,j]anthracene

Abstract

Preparation methods of dibenzoxanthene derivatives are surveyed alongside the synthesis of some of the titled compounds, which are the sulfur analogues of dibenzoxanthenes. Our new procedure for the conversion of phenols to thiophenols was used to prove the structure of such sulfur analogues.     

SBA-15/Metformin as a novel sorbent combined with surfactant-assisted dispersive liquid–liquid microextraction (SA-DLLME) for highly sensitive determination of Pb,Cd and Ni in food and environmental samples

This paper established a new, rapid and sensitive method for the ultra-trace determination of lead, cadmium and nickel in food and environmental samples preconcentrated by dispersive solid-phase extraction (DSPE) combined with surfactant-assisted dispersive liquid–liquid microextraction (SA-DLLME) prior to graphite furnace atomic absorption spectrometry. SBA-15/Met was synthesized and used as a new efficient sorbent for the extraction of metal ions in DSPE. It was characterized by TEM and TGA techniques. After DSPE step, stripped metal elements were complexed with dithizone, and then, the complexes were extracted into carbon tetrachloride by using SA-DLLME. A conventional nonionic surfactant, triton X-100 was used as a disperser agent. Under the optimized conditions, the limit of quantifications was found to be 2.5 ng L^?1 for Pb²⁺, Cd²⁺ and 5.0 ng L^?1 for Ni²⁺. The limits of detection were 1.5 ng L^?1 for Ni²⁺ and 0.75 ng L^?1 for Pb²⁺ and Cd²⁺, with enrichment factor of 1650. The optimized method exhibited a good precision level with relative standard deviations (RSDs%) values of 4.9, 5.2 and 5.0% for 1 μg L^?1 Pb²⁺, Cd²⁺ and Ni²⁺, respectively (n = 7). Application of the proposed method to the analysis of fish-certified reference material produced results that were in good agreement with the certified values.     

Synthesis of arylidenepyruvic amide derivatives via Ugi-four component condensation

Arylidenepyruvic acids (APAs) have been successfully employed in an Ugi-four component condensation reaction which yielded polyfunctional amides. Condensation of various APAs, aldehydes, amines, and isocyanides at room temperature in 96% ethanol as a green solvent proceeded in good yields. The extension of the reaction to diamines, formaldehyde, and isocyanides to form more complex molecules is also reported. These novel products may have potential in various pharmaceutical applications.     

Quantitative structure-activity relationship analysis of β-amyloid aggregation inhibitors

Inhibiting the aggregation process of the β-amyloid peptide is a promising strategy in treating Alzheimer’s disease. In this work, we have collected a dataset of 80 small molecules with known inhibition levels and utilized them to develop two comprehensive quantitative structure–activity relationship models: a Bayesian model and a decision tree model. These models have exhibited high predictive accuracy: 87% of the training and test sets using the Bayesian model and 89 and 93% of the training and test sets, respectively, by the decision tree model. Subsequently these models were used to predict the activities of several new potential β-amyloid aggregation inhibitors and these predictions were indeed validated by in vitro experiments. Key chemical features correlated with the inhibition ability were identified. These include the electro-topological state of carbonyl groups, AlogP and the number of hydrogen bond donor groups. The results demonstrate the feasibility of the developed models as tools for rapid screening, which could help in the design of novel potential drug candidates for Alzheimer’s disease.     

Mechanistic study of fenoprofen photoisomerization to pure (S)-fenoprofen: a DFT study

Structural Chemistry - This work provides a comprehensive DFT study on the conversion mechanism and photoisomerization of the effective and commonly used nonsteroidal anti-inflammatory medicine...