Convenient Synthesis of 14‐Aryl‐14‐H‐dibenzo[a,j]xanthenes Catalyzed by Acyclic Brønsted Acidic Ionic Liquid [H—NMP]+[HSO4]− under Microwave Irradiation

Efficient method for direct preparation of 14‐aryl‐14‐H‐dibenzo[a,j]xanthenes through condensation of β‐naphthol with various aromatic aldehydes in the presence of the catalytic amount of [H—NMP]⁺[HSO₄]^? under microwave irradiation was described. This method has the advantages such as; very easy reaction workup, absolute separation of catalyst from the reaction mixture and smooth recyclability of catalyst. In this reaction 14‐aryl‐14‐H‐dibenzo[a,j]xanthenes were obtained as desired products in excellent yields and short reaction times via green and one‐pot procedure.     

A novel and selective oxidation of benzylic alcohols with polymer-supported periodic acid under mild aprotic conditions

A new polymeric oxidizing reagent was prepared by supporting periodic acid on poly（1,4-phenylene-2,5-pyridine dicarboxyamide）. This polymeric reagent was used for the selective oxidation of primary benzylic alcohols to the corresponding benzaldehydes in CH₃CN at reflux conditions.Excellent selectivity was observed between primary benzyl alcohols and secondary ones as well as non-benzylic alcohols in the oxidation reactions.Allylic alcohols were also converted to the corresponding aldehydes with good yields.     

Novel glycosylated mycosporine-like amino acids with radical scavenging activity from the cyanobacterium Nostoc commune

Mycosporine-like amino acids (MAAs) are UV absorbing pigments, and structurally distinct MAAs have been identified in taxonomically diverse organisms. Two novel MAAs were purified from the cyanobacterium Nostoc commune, and their chemical structures were characterized. An MAA with an absorption maximum at 335 nm was identified as a pentose-bound porphyra-334 derivative with a molecular mass of 478 Da. Another identified MAA had double absorption maxima at 312 and 340 nm and a molecular mass of 1,050 Da. Its unique structure consisted of two distinct chromophores of 3-aminocyclohexen-1-one and 1,3-diaminocyclohexen and two pentose and hexose sugars. These MAAs had radical scavenging activity in vitro; the 1050-Da MAA contributed approximately 27% of the total radical scavenging activities in a water extract of N. commune. These results suggest that these glycosylated MAAs have multiple roles as a UV protectant and an antioxidant relevant to anhydrobiosis in N. commune.     

Structure–activity relationship of polyamine conjugates for uptake via polyamine transport system

Structural Chemistry - High toxicity of anticancer drugs led to development of targeted drug delivery directly to the specific organs. Polyamine transport system (PTS) of mammalian cells is one of...     

Electrochemical and mechanical characteristics of Al-(x)SiC composite fabricated by high energy compaction

Simultaneous compaction and sintering using the energy generated by the underwater explosion is a rapid method that does not have the negative consequences of normal sintering, such as unwanted reactions between components and grain growth. For this reason, this study used the energy from this process to produce Al/SiC composites with different amounts of SiC. As a result, 10, 20, and 30% of SiC powder were added to the Al powder, and then the samples were produced by compression under the influence of an underwater explosion. The results showed that as the amount of SiC increased, the samples' density and the amount of porosity for further agglomeration increased. Microstructural examination by Scanning Electron Microscopy (SEM) confirmed the increase in agglomeration with increasing SiC. Besides, Samples experienced an increase in hardness as the amount of SiC raised. Adding 10% of SiC increased the flexural strength while adding more (20 and 30%) increased the agglomeration resulting in a decrease in strength and elongation. Polarization and impedance spectroscopy (EIS) methods were used to study the samples' electrochemical behavior in a 3.5% NaCl solution. Results showed that the addition of SiC particles up to 10% (wt%) reduces the corrosion density from 9.7 (μA/cm²) to 2.06 (μA/cm²). The Al–10%SiC composite had the lowest corrosion current density compared to 20% and 30% SiC composites. In addition, the polarization resistance of the Nyquist plot for pure Al and Al composite containing 10% SiC was 3965 and 7862, respectively. Therefore, these results showed the beneficial effect of 10% SiC as reinforcing particles on the corrosion behavior of Al composites and thus improved corrosion resistance.     

Determination of Activity Coefficients at Infinite Dilution of Solutes in New Dicationic Ionic Liquids Based on Morpholine Using Gas–Liquid Chromatography

The activity coefficients at infinite dilution for 14 either polar or non-polar compounds have been determined in four room temperature dicationic ionic liquids, with the stationary phases loading between 10 and 20 %. The experiments were carried out at different temperatures between 308 and 323 K. Four new Ionic liquids (ILs), C9(methylmorpholine)₂ (NTf₂)₂, C9(ethylmorpholine)₂(NTf₂)₂, C12(methylmorpholine)₂(NTf₂)_2, and C12(ethylmorpholine)₂(NTf₂)₂ were investigated because of their higher viscosity and thermal stability in comparison with mono-cationic ILs. The obtained results showed that inverse gas chromatography is a useful method for examination of physiochemical properties of various materials. The partial molar excess enthalpies at infinite dilution, $ H_{ 1}^{{{\text{E}},\infty }} $ of the solutes were also derived from the temperature dependence of the γ _i∞ values. The selectivity values ( $ S_{ij}^{\infty } $ ) which have been calculated in 323 K indicate that these ILs can be used as efficient solvents in aromatic–aliphatic separations.

Synthesis,molecular docking studies,and absorption,distribution, metabolism,and excretion prediction of novel sulfonamide derivatives as antibacterial agents

A series of novel sulfonamide‐amide derivatives were synthesized from 3‐(2,4 dichlorophenylamino)‐3‐oxopropane‐1‐sulfonylchloride and a variety of amines under solvent‐free conditions at room temperature. 3‐(2,4‐dichlorophenylamino)‐3‐oxopropane‐1 sulfonylchloride was synthesized in four steps starting from 2,4‐dichloroaniline and chloropropanoic acid in good yield and purity. The synthesized compounds were screened for their in vitro antibacterial activity against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 29213). Molecular docking of sulfonamide derivatives into S. aureus tyrosyl‐tRNA synthetase (TyrRS)‐active site was also performed and among these, 5m and 5g tightly fit the active sites that might be inhibitors of TyrRS for further investigations. Also in the silico metabolism profile, drug‐like properties and absorption, distribution, metabolism, excretion and toxicity (ADMET) of the title compounds were calculated by the preADMET server.     

Uranyl Schiff base complexes as new heterogeneous catalysts for halogen exchange reactions between alkyl halides and elemental halogens

Mild and effective procedure for the halogen exchange reaction of alkyl halides with elemental iodine and bromine catalyzed with uranyl Schiff base complexes in various aprotic solvents was developed. Corresponding alkyl bromides and iodides were obtained with high yields within 20—70 min. The structures of the target products were confirmed by physical and spectroscopic data.     

Solvent-Free Synthesis,ADME Prediction,and Evaluation of Antibacterial Activity of Novel Sulfonamide Derivatives

Russian Journal of Organic Chemistry - A series of novel sulfonamides containing a 2-amino-1,3-thiazole fragment have been synthesized using a simple and efficient method under solvent-free...     

New strategy for the preparation of imidazole derivatives containing thiazole ring via ring opening/coupling/cyclization/decarboxylation cascade

The aim of this work is to investigate the three-component reaction of 6-aminopenicillinic acid, aldehydes and ammonium acetate. The work was used SiO₂-H₂SO₄ as a catalyst to promote the reaction under solvent-free conditions. A series of 5,5-dimethyl-2-(2-aryl-1H-imidazol-5-yl)-2,5-dihydrothiazole derivatives were obtained as the main product by this method.