Extending Time Profile of Morphine‐Induced Analgesia Using a Chitosan‐Based Molecular Imprinted Polymer Nanogel

Chitosan‐based molecular imprinted polymer (CS‐MIP) nanogel is prepared in the presence of morphine template, fully characterized and used as a new vehicle to extend duration of morphine analgesic effect in Naval Medical Research Institute mice. The CS‐MIP nanogel with ≈25 nm size range exhibits 98% loading efficiency, and in vitro release studies show an initial burst followed by an extended slow release of morphine. In order to study the feasibility of CS‐MIP nanogel as morphine carrier, 20 mice are divided into two groups randomly and received subcutaneous injection of morphine‐loaded CS‐MIP and morphine (10 mg kg^?1) dissolved in physiologic saline. Those received injection of morphine‐loaded CS‐MIP show slower and long lasting release of morphine with 193 min effective time of 50% (ET50) analgesia compared to 120 min ET50 in mice received morphine dissolved in physiologic saline. These results suggest that CS‐MIP nanogel can be a possible strategy as morphine carrier for controlled release and extension of its analgesic efficacy.

     

Conformational study of a strained tolanophane by dynamic 1H NMR spectroscopy and computational methods

The existence of a short C–H ⋯ π (alkyl–alkyne) interaction in the structure of a strained and relatively rigid tolanophane is expected to hinder the rotation about the C–C sp³ single bond. Variable-temperature NMR experiments (performed in three solvents, CDCl₃, THF-d₈, and acetone-d₆) and ab initio density functional calculations were carried out to investigate its dynamic nature. An energy barrier of 48.6 kJ/mol is determined at coalescence (210 K) with acetone-d₆ which is in good agreement with calculation result (54 kJ/mol). Correspondence: Hossein Reza Darabi, Chemistry and Chemical Engineering Research Center of Iran, Pajoohesh Blvd., km 17, Karaj Hwy, 14968-13151 Tehran, Iran.     

Reactions of Benzoyl Isothiocyanate with Active Methylene Reagents: A Novel Synthesis of Thiophene,Thiazoline and Thieno[2,3-d]Pyrimidine Derivatives

Various derivatives of thiophene, thiazoline and thienopyrimidine have been synthesized via the reaction of active methylene reagents (la-j) with benzoyl isothiocyanate in the presence of potassium hydroxide, followed by the subsequent treatment of the potassium salt intermediates 2a-j with phenacyl bromide or ethyl chloroacetate. The stability of the formed adducts 3 and 12 or their selective cyclization depends on both the nature of the active methylene reagent and the α-halocarbonyl compounds.     

More radiative corrections for β-decay

A calculation is performed of a hitherto ignored “radiative” correction to neutron β-decay. Conventional electromagnetism does not allow η → 3π decay; the mechanism responsible for this decay will lead to a correction to β-decay not taken into account by the standard O(α/π) coreection of one-photon exchange. While an order of magnitude estimate indicates this correction could in principle compete with the one-photon-exchange correction, explicit calculation puts it at three orders of magnitude down. Thus the agreement between the Cabibbo cosθ and the sinθ obtained from ΔS = 1 decays remains unspoilt.     

Starved Water Hydrolysis of Different Precursors and its Influence on the Properties of Precipitated Zirconia

The chemical composition of zirconia gels precipitated from methanol solutions with excess, stoichiometric or deficient amounts of water as well, as the phase composition of fine ZrO₂ powders obtained by thermal treatment of gels prepared by this method, were investigated. It was observed that both the stoichiometry and crystalline phase formation during thermal treatment of zirconia gels are strongly influenced by the amount of water added to the initial reaction mixture. Heating the hydrated zirconia gels in an inert oxygen-free atmosphere produced a black nonstoichiometric oxide. The degree of nonstoichiometry of zirconia and its microstructure are influenced by the initial conditions in the reaction mixture. The X-ray patterns of thermally treated samples prepared with a substoichiometric amount of water show power lines of monoclinic and tetragonal zirconia, while after the same thermal treatment to 700°C, those prepared with excess water in the initial methanol solution, show mainly tetragonal diffraction lines.     

Simultaneous Determination of Nickel(II) and Copper(II) by Second‐Derivative Spectrophotometric Method in Micellar Media

A second‐derivative spectrophotometric method based on zero‐crossing over technique is developed in simultaneous determination of copper(II) and nickel(II) ions. Methylthymol blue (MTB) as a chromogenic reagent and cetyltrimethylammonium bromide as a surfactant were used, and measurements were carried out in buffered solution at pH 6 and at a temperature of 25 °C. The amplitude of derivative spectra was measured at wavelengths of 631.9 and 587.7 nm for the simultaneous determination of Ni²⁺ and Cu²⁺, respectively. Linearity was obtained in the range of 0.5–5.0 μg mL^?1 for both ions in the presence of 0.0–5.0 μg mL^?1 of the other ion as an interfering ion. IUPAC detection limits for Cu²⁺ and Ni²⁺ ions were obtained at 0.48 and 0.43 μg mL^?1, respectively. The proposed procedure has been applied successfully for the simultaneous determination of copper and nickel in synthetic binary mixtures and real samples.     

Catalytic reduction of 4-nitrophenol by means of nanostructured polymeric Schiff base complexes

Polymeric Schiff base ligands were synthesized using 2-hydroxybenzaldehyde (L²), 4-hydroxy-3-methoxybenzaldehyde (L⁴), and 5-aminoisophthalic acid. The nanostructured complexes were then synthesized using Ni²⁺, Cu²⁺, and Mn³⁺. The ligands and complexes thus synthesized were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy. The thermal stability of the complexes was confirmed using TGA. The synthesized complexes were used as catalysts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol in an aqueous phase in the presence of sodium borohydride. In this work, the catalytic reactivity of nanostructured complexes was compared using the rate constant (k) of the reaction. The reaction time for the reduction of 4-NP was 5–14 min for different complexes. The catalytic system based on Ni²⁺/2-hydroxybenzaldehyde was the most active and displayed reusability in the reduction of 4-NP.     

A catalytic synthesis of dihydrofuran-3(2H)-imine skeletons from isocyanides,terminal alkynes,and oxiranes

In this catalytic multicomponent reaction, the nucleophilicity of terminal alkynes and isocyanides towards oxiranes has been explored. The reaction outcome depends highly on solvent, bases, and catalysts sources. An array of terminal alkynes, isocyanides, and oxiranes has been examined to explore the of this transformation. The reactions proceeded through S_N2 path and in regioselective manner.