Docking and Molecular Dynamic Investigations of Phenylspirodrimanes as Cannabinoid Receptor-2 Agonists

Cannabinoid receptor ligands are renowned as being therapeutically crucial for treating diverse health disorders. Phenylspirodrimanes are meroterpenoids with unique and varied structural scaffolds, which are mainly reported from the Stachybotrys genus and display an array of bioactivities. In this work, 114 phenylspirodrimanes reported from Stachybotrys chartarum were screened for their CB2 agonistic potential using docking and molecular dynamic simulation studies. Compound 56 revealed the highest docking score (−11.222 kcal/mol) compared to E3R_6KPF (native agonist, gscore value −12.12 kcal/mol). The molecular docking and molecular simulation results suggest that compound 56 binds to the putative binding site in the CB2 receptor with good affinity involving key interacting amino acid residues similar to that of the native ligands, E3R. The molecular interactions displayed π–π stacking with Phe183 and hydrogen bond interactions with Thr114, Leu182, and Ser285. These findings identified the structural features of these metabolites that might lead to the design of selective novel ligands for CB2 receptors. Additionally, phenylspirodrimanes should be further investigated for their potential as a CB2 ligand.     

Optimisation and characterisation of marihuana extracts obtained by supercritical fluid extraction and focused ultrasound extraction and retention time locking GC‐MS

The optimisation of focused ultrasound extraction and supercritical fluid extraction of volatile oils and cannabinoids from marihuana has been accomplished by experimental design approach. On the one hand, the focused ultrasound extraction method of volatile compounds and cannabinoids was studied based on the optimisation of cyclohexane and isopropanol solvent mixtures, and the instrumental variables. The optimal working conditions were finally fixed at isopropanol/cyclohexane 1:1 mixture, cycles (3 s^?1), amplitude (80%) and sonication time (5 min). On the other hand, the supercritical fluid extraction method was optimised in order to obtain a deterpenation of the plant and a subsequent cannabinoid extraction. For this purpose, pressure, temperature, flow and co‐solvent percentage were optimised and the optimal working conditions were set at 100 bar, 35°C, 1 mL/min, no co‐solvent for the terpenes and 20% of ethanol for the cannabinoids. Based on the retention time locking GC‐MS analysis of the supercritical fluid extracts the classification of the samples according to the type of plant, the growing area and season was attained. Finally, three monoterpenes and three cannabinoids were quantified in the ranges of 0.006–6.2 μg/g and 0.96–324 mg/g, respectively.     

Morphological,electrochemical and photoelectrochemical characterization of nanotubular TiO2 synthetized electrochemically from different electrolytes

The electrochemical synthesis of auto-organized TiO₂ arrays generated by Ti anodization in different non-aqueous electrolytes was analyzed. Propylene carbonate-based electrolytes seem to be good electrolytic media for the controlled growth of titania nanotube structures. Scanning electron microscopy (SEM) analysis indicated that, depending on the media employed in the synthesis of the TiO₂ nanotubes, different aspect ratios (length/diameter) could be obtained. Impedance analysis using the passive pit model gave the electrical properties of the layers during the different stages of nanotubes formation. Mott–Schottky analysis and the impedance results showed that the TiO₂ nanotubes layers were n-type semiconductors with highly defective walls on top of a resistive barrier layer. Photoelectrochemical measurements showed that tetra(4-carboxyphenyl)porphyrin (TCPP) adsorbed onto the TiO₂ nanotube arrays, which could be employed as an efficient photosensitizer for solar-energy conversion by TCPP-sensitized nanotubular TiO₂ electrodes.     

Original synthesis of 2-substituted-4,11-dimethoxy-1-(phenylsulfonyl)-2,3-dihydro-1H-naphtho[2,3-f]indole-5,10-diones using TDAE and Cu-catalyzed reaction strategy

We report herein an original and rapid synthesis of 2-substituted-4,11-dimethoxy-1-(phenylsulfonyl)-2,3-dihydro-1H-naphtho[2,3-f]indole-5,10-diones by TDAE mediated synthesis of N-benzylsulfonamides followed by an intramolecular N-arylation using Cu-catalyzed system.     

Thermal analytical study of different phases of potassium hexacyanoferrate(II) crystal

Summary The unit cell parameters of virgin and thermally treated potassium hexacyanoferrate(II)trihydrate (KFCT) crystals are measured at room temperature. Considerable changes in the lattice constants are observed for as-grown or pre-cooled to the liquid nitrogen temperature samples after heating up to selected higher temperatures for different times. The detected variations may be due to partial or total removal of the three water molecules of crystallization and the transformation of Fe²⁺ to Fe³⁺. DSC, DTA and TG are used to study physical and chemical changes associated with the observed crystallographic variations. The effect of γ-irradiation with a dose of 5×10⁵ Gy on the crystal structure of KFCT is also examined. Two computer software programs are used to analyze the data of the X-ray diffraction patterns and the results are compared.     

Synthesis,characterization and antimicrobial activity of a bidentate NS Schiff base of S-benzyl dithiocarbazate and its divalent complexes

The reaction of S-benzyl dithiocarbazate (SBDTC) with 2,4,5-trimethoxybenzaldehyde afforded a bidentate NS Schiff base 1 (benzyl-3-N-(2,4,5-trimethoxyphenylmethylenehydrazine carbodithioate), which on further reaction with M(II) (where M(II) = nickel(II), zinc(II), palladium(II) and copper(II)) in ethanol under reflux yielded bis-chelated inner complexes [ML₂] 2–5 with deprotonated L. The ligand and its complexes were characterized by physicochemical techniques, viz., molar conductance, magnetic susceptibility measurement, IR, NMR, UV–Vis and mass spectroscopic techniques. The crystal structures of 1 and 5 were also determined by single-crystal X-ray crystallography. The crystal structure analysis showed that the ligand exists in its thione tautomeric form. In the complexes, each of the two deprotonated ligands chelated the metal ions through the β-nitrogen and the thione sulfur forming five-membered rings. The copper(II) complex (5) exhibited a square-planar geometry, where the two N₂S₂ chromophores are arranged trans. All the compounds showed strong antibacterial activity against S.-β-hemolyticus, Klebsiella pneumoni, and Escherichia coli. The compounds also showed strong antifungal activity against Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, and Candida albicans with the exception of the palladium(II) complex (4) which showed no activity, while all the compounds showed no activity against Fusarium vasinfectum.     

Excited-state structure determination of the green fluorescent protein chromophore

Ultrafast polarization-sensitive infrared (IR) spectroscopy of the C=O stretching mode of the chromophore of the green fluorescent protein reveals a near complete twisting around the ethylenic bridge between the phenolate and imidazolidinone groups upon electronic excitation, hinting at a decisive role of this motion in the efficient internal conversion process.     

An amphiphilic graft copolymer as a surface-modifying additive for poly(methyl methacrylate)

An amphiphilic graft copolymer was prepared by transesterification of poly(2-ethylhexyl acrylate-co-methyl methacrylate) with poly(ethylene glycol) monomethyl ether (MPEG2000). The grafting reaction was performed in melt at 155°C. The purified graft copolymer was blended into poly(methyl methacrylate) in concentrations of 1.5-30 wt %, either by mixing in chloroform solution or by melt mixing by means of a twin-screw extruder or a Brabender blender. Films of the blends were prepared by solution casting onto glass plates or by hot pressing between polished Al plates. At concentrations up to 20% of the graft copolymer homogeneous blends were obtained. At higher concentrations the blends were heterogeneous, and side-chain crystallinity was detectable by DSC analysis. The surface properties of the films were studied by measurements of water contact angles. The surface accumulation of the graft copolymer was demonstrated as a large increase in the wetting angle hysteresis, and found to depend on the procedure for film preparation as well as the casting substrate. © 1995 John Wiley & Sons, Inc.     

The (E)/(Z)-ratio in the reaction of 5-(2-aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidines with bromine

Summary 3-Aryl-, 3-benzyl-, and 3H-5-(2-aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidines3a–h react with bromine in acetic acid solution to give mixtures of the respective 5-aroylmethylene (E) and (Z) diastereomeric derivatives5 and6. They contain more than 85% of the (E)-diastereomers along with some pure isomers. The intermediacy of the 5-bromo derivatives4 is proven and a plausible route of the reaction is presented. Structures of compounds3–6 are evidenced by analytical and spectral data.

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Das Verhältnis von (E)- und (Z)-Isomeren bei der Reaktion von 5-(2-Aryl-2-oxomethyl)-2-thioxo-4-oxo-1,3-thiazolidinen mit Brom

Zusammenfassung 3-Aryl-, 3-Benzyl- und 3H-5-(2-Aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidine3a–h reagieren mit Brom in essigsaurer Lösung zu Gemischen der entsprechenden diastereomeren 5-Arylmethylen-Derivate ((E) und (Z))5 und6. Sie enthalten mehr als 85% des (E)-Diastereomeren. Die intermediäre Natur der 5-Brom-Derivate4 wird bewiesen; ein Reaktionsweg wird vorgeschlagen. Die Strukturen der Verbindungen3–6 werden durch analytische und spektroskopische Daten abgesichert.

     

Templated Atom‐Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18]− Nanocluster

Synthesis of atom‐precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag₂₄Au(SR)₁₈]^? cluster (SR: thiolate) using a pure [Ag₂₅(SR)₁₈]^? cluster as a template. Conversely, the direct synthesis of Ag₂₄Au cluster leads to a mixture of [Ag_25?xAu_x(SR)₁₈]^?, x=1–8. Mass spectrometry and crystallography of [Ag₂₄Au(SR)₁₈]^? reveal the presence of the Au heteroatom at the Ag₂₅ center, forming Ag₂₄Au. The successful exchange of the central Ag of Ag₂₅ with Au causes perturbations in the Ag₂₅ crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag₂₅ and Ag₂₄Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single‐atom level.