Biosynthesis of Fe3O4-magnetic nanoparticles using clover leaf aqueous extract: Green synthesis of 1,3-benzoxazole derivatives

In this research, magnetic Fe₃O₄-NP nanoparticles were synthesized employing a green biosynthetic procedure by reduction of ferric chloride solution with clover leaf water extract. The nanoparticles prepared via this biosynthesis method can potentially be valuable for different purposes such as organic synthesis. In this research, 1,3-benzoxazole derivatives were generated via a multicomponent reaction of α-bromo ketones, isothiocyanate, and propiolate in the presence of a catalytic amount of bio-Fe₃O₄ MNPs and sodium hydride in water at 50°C in good yields. The catalyst was reused five times with a minor decrease in its catalytic activity.     

Viscosities and Refractive Indices of Binary Mixtures of Dimethylsulphoxide with Some Aromatic Hydrocarbons at Different Temperatures: An Experimental and Theoretical Study

The viscosities, η, and refractive indices, n, of pure dimethylsulphoxide (DMSO), benzene, toluene, o‐xylene, m‐xylene, p‐xylene and mesitylene, and those of their 54 binary mixtures, with DMSO as common component, covering the whole composition range have been measured at 298.15, 303.15, 308.15, 313.15, and 318.15 K. From the experimental data, the deviations in viscosity, Δη and deviations in molar refraction, ΔR_m have been calculated. The variation of these parameters with composition and temperature of the mixtures have been discussed in terms of molecular interaction in these mixtures. The effect of the number and position of the methyl groups in these aromatic hydrocarbons on molecular interactions in these mixtures has also been discussed. The free energies, ΔG^*, enthalpies, ΔH^* and entropies, ΔS^* of activation of viscous flow have also been obtained by using Eyring viscosity equation. The ΔH^* values were found independent of temperature. The dependence of these thermodynamic parameters on composition of the mixtures has been discussed. Further, the viscosities and refractive indices of these binary mixtures were calculated theoretically from pure component data by using various empirical and semi‐empirical relations and the results were compared with the experimental findings.     

Synthesis of potential biologically active 1,2-benzothiazin-3-yl-quinazolin-4(3H)-ones

A series of potential biologically active 2-(4-hydroxy-1,1-dioxido-2H-1,2-benzothiazin-3-yl)quinazolin-4(3H)-ones was synthesized in a straight forward manner by condensation of respective 4-hydroxy-1,2-benzothiazine-1,1-dioxides with anthranilamide followed by simple and high throughput cyclization of N-[2-(aminocarbonyl)phenyl]-4-hydroxy-1,2-benzothiazine-3-carboxamide-1,1-dioxides. All the synthesized compounds were subjected to preliminary evaluation for their biological activity against Gram positive and Gram negative bacteria. Some of the assayed compounds showed marked activity against Bacillus subtilis.     

N‐{4‐Bromo‐2‐[(3‐bromo‐1‐phenylsulfonyl‐1H‐indol‐2‐yl)methyl]‐5‐methoxyphenyl}acetamide

In the title compound, C₂₄H₂₀Br₂N₂O₄S, the indole ring system is planar and the S atom has a distorted tetrahedral configuration. The sulfonyl‐bound phenyl ring is orthogonal to the indole ring system and the conformation of the phenyl­sulfonyl substituent with respect to the indole moiety is influenced by intramolecular C—H⃛O hydrogen bonds involving the two sulfonyl O atoms. The mean plane through the acetyl­amido group makes a dihedral angle of 57.0 (1)° with the phenyl ring of the benzyl moiety. In the crystal, glide‐related mol­ecules are linked together by N—H⃛O hydrogen bonds and C—H⃛π interactions to form molecular chains, which extend through the crystal. Inversion‐related chains are interlinked by C—H⃛π interactions to form molecular layers parallel to the bc plane. These layers are interconnected through π–π interactions involving the five‐ and six‐membered rings of the indole moiety.     

meso‐Bis­(phenyl­sulfinyl)­methane

The title compound, meso‐C₁₃H₁₂O₂S₂, is in an anti conformation, with R and S configurations around the S atoms. The two O atoms are trans to each other, and the same applies for the two benzene rings. The phenyl­sulfinyl groups are nearly orthogonal to the central di­thio­methane group, and the orientation of the two phenyl rings are determined by the interactions in which they are involved. The packing is built from molecular columns stabilized by weak C—H⋯O interactions.     

Switchable Hydrophilicity Solvent-Based Homogenous Liquid–Liquid Microextraction (SHS-HLLME) Combined with GC-FID for the Quantification of Methadone and Tramadol

In this work, a new method based on homogeneous liquid-phase microextraction was developed for the determination of methadone and tramadol. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible/immiscible upon the addition or removal of CO₂ as a reagent. The effects of operational parameters of the extraction such as volume of acceptor phase, volume of donor phase, pH of donor phase, and ionic strength of solution were investigated. Under optimal conditions, the preconcentration factors, the detection limits and the linearity of the method were achieved in the ranges of 135–138, 1.2 and 4–1000 µg L^?1, respectively. Finally, the proposed method has been successfully applied to the analysis of methadone and tramadol in urine samples. In urine sample, the preconcentration factors were 118 and 122 for methadone and tramadol, respectively. Additionally, calibration curves were found to be linear in the concentration range of 8–1000 µg L^?1 with the r² values better than 0.998. In addition, limits of detection and quantification were 2.4 and 8 µg L^?1, respectively, for both analytes.     

Aggregation dependent fluorescence switching in benzothiazole derivative based H-bonded mesogen

In this work, hydrogen-bonded liquid crystal exhibiting phase dependent fluorescence has been reported. The H-bonded materials were prepared using pyridenyl benzothiazole and alkoxy benzoic acid as H-bond acceptor and donor respectively. The formation of the target materials was confirmed via different spectroscopic technique and their mesogenic behaviour has been studied through polarising optical microscope, differential scanning calorimetry and 2D-X-ray diffraction. The H-bonded mesogenic material showed aggregation dependent fluorescence switching when subjected to transformation from isotropic-nematic-crystalline phase sequence. Computational studies were performed to probe into fluorescence switching behaviour of the mesogenic material.